计算机j2ee动态配置中英文对照外文翻译文献

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MVC框架中英文对照外文翻译文献

MVC框架中英⽂对照外⽂翻译⽂献中英⽂对照外⽂翻译⽂献(⽂档含英⽂原⽂和中⽂翻译)译⽂：Web 2.0下的Spring MVC框架摘要 - 当要建⽴丰富⽤户体验的WEB应⽤时，有⼤量的WED应⽤框架可以使⽤，却很少有该选择哪⼀种的指导。

WEB 2.0应⽤允许个体管理他们⾃⼰的在线⽹页，并能与其他在线⽤户和服务器共享。

这样分享需要访问控制器来实现。

然⽽，现有的访问控制器解决⽅案不是令⼈很满意。

因为在开放且由⽤户主导的WEB环境下，它满⾜不了⽤户的功能需求。

MVC框架是在所有的WEB开发框架中最受欢迎的。

模型-视图-控制器（MVC）是⼀种软件架构，如今被认为是⼀种体系结构在软件⼯程模式中使⽤。

该模式从⽤户界⾯（输⼊和演⽰）分离出了“领域逻辑”（基于⽤户的应⽤逻辑），它允许独⽴地开发，测试和维护每个分离的部分。

模型-视图-控制器（MVC）模型创建的应⽤分离为不同的层次应⽤，同时在每两者之间建⽴松散的耦合。

关键字 - Spring MVC, 结构， XStudio, SOA, 控制器I.绪论如何确切地定义⼀个⽹站为“WEB 2.0”的呢？关于这有着许多不同见解，使它很难精确地下⼀个确切的定论。

但当我们将所有的WEB开发框架过⼀遍之后它就会变得清晰了。

各种基于WEB开发的架构如下：●Ntier架构（Ntier Architecture）在软件⼯程中，多层架构（常被称为n-tier架构）是⼀种表⽰层，应⽤处理层和数据管理层在逻辑上分开处理的客户端-服务器架构。

例如，⼀个应⽤在⽤户与数据库之间使⽤中间件提供数据请求服务就⽤到了多层体系结构。

最为⼴泛应⽤的多层体系结构是三层架构。

N-tier 应⽤架构为开发者提供了⽤来创建了⼀个灵活且可复⽤的模型。

通过打破应⽤层次，开发者只需修改或添加⼀个特定的层，⽽不是要去重写⼀遍整个应⽤。

它需要有⼀个表⽰层，⼀个业务层或者数据访问层和⼀个数据层。

层（layer）和层(tier)之间的概念常常是可以互换的。

计算机java外文翻译外文文献英文文献

英文原文:Title: Business Applications of Java. Author: Erbschloe, Michael, Business Applications of Java -- Research Starters Business, 2008DataBase: Research Starters - BusinessBusiness Applications of JavaThis article examines the growing use of Java technology in business applications. The history of Java is briefly reviewed along with the impact of open standards on the growth of the World Wide Web. Key components and concepts of the Java programming language are explained including the Java Virtual Machine. Examples of how Java is being used bye-commerce leaders is provided along with an explanation of how Java is used to develop data warehousing, data mining, and industrial automation applications. The concept of metadata modeling and the use of Extendable Markup Language (XML) are also explained.Keywords Application Programming Interfaces (API's); Enterprise JavaBeans (EJB); Extendable Markup Language (XML); HyperText Markup Language (HTML); HyperText Transfer Protocol (HTTP); Java Authentication and Authorization Service (JAAS); Java Cryptography Architecture (JCA); Java Cryptography Extension (JCE); Java Programming Language; Java Virtual Machine (JVM); Java2 Platform, Enterprise Edition (J2EE); Metadata Business Information Systems > Business Applications of JavaOverviewOpen standards have driven the e-business revolution. Networking protocol standards, such as Transmission Control Protocol/Internet Protocol (TCP/IP), HyperText Transfer Protocol (HTTP), and the HyperText Markup Language (HTML) Web standards have enabled universal communication via the Internet and the World Wide Web. As e-business continues to develop, various computing technologies help to drive its evolution.The Java programming language and platform have emerged as major technologies for performing e-business functions. Java programming standards have enabled portability of applications and the reuse of application components across computing platforms. Sun Microsystems' Java Community Process continues to be a strong base for the growth of the Java infrastructure and language standards. This growth of open standards creates new opportunities for designers and developers of applications and services (Smith, 2001).Creation of Java TechnologyJava technology was created as a computer programming tool in a small, secret effort called "the Green Project" at Sun Microsystems in 1991. The Green Team, fully staffed at 13 people and led by James Gosling, locked themselves away in an anonymous office on Sand Hill Road in Menlo Park, cut off from all regular communications with Sun, and worked around the clock for18 months. Their initial conclusion was that at least one significant trend would be the convergence of digitally controlled consumer devices and computers. A device-independent programming language code-named "Oak" was the result.To demonstrate how this new language could power the future of digital devices, the Green Team developed an interactive, handheld home-entertainment device controller targeted at the digital cable television industry. But the idea was too far ahead of its time, and the digital cable television industry wasn't ready for the leap forward that Java technology offered them. As it turns out, the Internet was ready for Java technology, and just in time for its initial public introduction in 1995, the team was able to announce that the Netscape Navigator Internet browser would incorporate Java technology ("Learn about Java," 2007).Applications of JavaJava uses many familiar programming concepts and constructs and allows portability by providing a common interface through an external Java Virtual Machine (JVM). A virtual machine is a self-contained operating environment, created by a software layer that behaves as if it were a separate computer. Benefits of creating virtual machines include better exploitation of powerful computing resources and isolation of applications to prevent cross-corruption and improve security (Matlis, 2006).The JVM allows computing devices with limited processors or memory to handle more advanced applications by calling up software instructions inside the JVM to perform most of the work. This also reduces the size and complexity of Java applications because many of the core functions and processing instructions were built into the JVM. As a result, software developersno longer need to re-create the same application for every operating system. Java also provides security by instructing the application to interact with the virtual machine, which served as a barrier between applications and the core system, effectively protecting systems from malicious code.Among other things, Java is tailor-made for the growing Internet because it makes it easy to develop new, dynamic applications that could make the most of the Internet's power and capabilities. Java is now an open standard, meaning that no single entity controls its development and the tools for writing programs in the language are available to everyone. The power of open standards like Java is the ability to break down barriers and speed up progress.Today, you can find Java technology in networks and devices that range from the Internet and scientific supercomputers to laptops and cell phones, from Wall Street market simulators to home game players and credit cards. There are over 3 million Java developers and now there are several versions of the code. Most large corporations have in-house Java developers. In addition, the majority of key software vendors use Java in their commercial applications (Lazaridis, 2003).ApplicationsJava on the World Wide WebJava has found a place on some of the most popular websites in the world and the uses of Java continues to grow. Java applications not only provide unique user interfaces, they also help to power the backend of websites. Two e-commerce giants that everybody is probably familiar with (eBay and Amazon) have been Java pioneers on the World Wide Web.eBayFounded in 1995, eBay enables e-commerce on a local, national and international basis with an array of Web sites-including the eBay marketplaces, PayPal, Skype, and -that bring together millions of buyers and sellers every day. You can find it on eBay, even if you didn't know it existed. On a typical day, more than 100 million items are listed on eBay in tens of thousands of categories. Recent listings have included a tunnel boring machine from the Chunnel project, a cup of water that once belonged to Elvis, and the Volkswagen that Pope Benedict XVI owned before he moved up to the Popemobile. More than one hundred million items are available at any given time, from the massive to the miniature, the magical to the mundane, on eBay; the world's largest online marketplace.eBay uses Java almost everywhere. To address some security issues, eBay chose Sun Microsystems' Java System Identity Manager as the platform for revamping its identity management system. The task at hand was to provide identity management for more than 12,000 eBay employees and contractors.Now more than a thousand eBay software developers work daily with Java applications. Java's inherent portability allows eBay to move to new hardware to take advantage of new technology, packaging, or pricing, without having to rewrite Java code ("eBay drives explosive growth," 2007).Amazon (a large seller of books, CDs, and other products) has created a Web Service application that enables users to browse their product catalog and place orders. uses a Java application that searches the Amazon catalog for books whose subject matches a user-selected topic. The application displays ten books that match the chosen topic, and shows the author name, book title, list price, Amazon discount price, and the cover icon. The user may optionally view one review per displayed title and make a buying decision (Stearns & Garishakurthi, 2003).Java in Data Warehousing & MiningAlthough many companies currently benefit from data warehousing to support corporate decision making, new business intelligence approaches continue to emerge that can be powered by Java technology. Applications such as data warehousing, data mining, Enterprise Information Portals (EIP's), and Knowledge Management Systems (which can all comprise a businessintelligence application) are able to provide insight into customer retention, purchasing patterns, and even future buying behavior.These applications can not only tell what has happened but why and what may happen given certain business conditions; allowing for "what if" scenarios to be explored. As a result of this information growth, people at all levels inside the enterprise, as well as suppliers, customers, and others in the value chain, are clamoring for subsets of the vast stores of information such as billing, shipping, and inventory information, to help them make business decisions. While collecting and storing vast amounts of data is one thing, utilizing and deploying that data throughout the organization is another.The technical challenges inherent in integrating disparate data formats, platforms, and applications are significant. However, emerging standards such as the Application Programming Interfaces (API's) that comprise the Java platform, as well as Extendable Markup Language (XML) technologies can facilitate the interchange of data and the development of next generation data warehousing and business intelligence applications. While Java technology has been used extensively for client side access and to presentation layer challenges, it is rapidly emerging as a significant tool for developing scaleable server side programs. The Java2 Platform, Enterprise Edition (J2EE) provides the object, transaction, and security support for building such systems.Metadata IssuesOne of the key issues that business intelligence developers must solve is that of incompatible metadata formats. Metadata can be defined as information about data or simply "data about data." In practice, metadata is what most tools, databases, applications, and other information processes use to define, relate, and manipulate data objects within their own environments. It defines the structure and meaning of data objects managed by an application so that the application knows how to process requests or jobs involving those data objects. Developers can use this schema to create views for users. Also, users can browse the schema to better understand the structure and function of the database tables before launching a query.To address the metadata issue, a group of companies (including Unisys, Oracle, IBM, SAS Institute, Hyperion, Inline Software and Sun) have joined to develop the Java Metadata Interface (JMI) API. The JMI API permits the access and manipulation of metadata in Java with standard metadata services. JMI is based on the Meta Object Facility (MOF) specification from the Object Management Group (OMG). The MOF provides a model and a set of interfaces for the creation, storage, access, and interchange of metadata and metamodels (higher-level abstractions of metadata). Metamodel and metadata interchange is done via XML and uses the XML Metadata Interchange (XMI) specification, also from the OMG. JMI leverages Java technology to create an end-to-end data warehousing and business intelligence solutions framework.Enterprise JavaBeansA key tool provided by J2EE is Enterprise JavaBeans (EJB), an architecture for the development of component-based distributed business applications. Applications written using the EJB architecture are scalable, transactional, secure, and multi-user aware. These applications may be written once and then deployed on any server platform that supports J2EE. The EJB architecture makes it easy for developers to write components, since they do not need to understand or deal with complex, system-level details such as thread management, resource pooling, and transaction and security management. This allows for role-based development where component assemblers, platform providers and application assemblers can focus on their area of responsibility further simplifying application development.EJB's in the Travel IndustryA case study from the travel industry helps to illustrate how such applications could function. A travel company amasses a great deal of information about its operations in various applications distributed throughout multiple departments. Flight, hotel, and automobile reservation information is located in a database being accessed by travel agents worldwide. Another application contains information that must be updated with credit and billing historyfrom a financial services company. Data is periodically extracted from the travel reservation system databases to spreadsheets for use in future sales and marketing analysis.Utilizing J2EE, the company could consolidate application development within an EJB container, which can run on a variety of hardware and software platforms allowing existing databases and applications to coexist with newly developed ones. EJBs can be developed to model various data sets important to the travel reservation business including information about customer, hotel, car rental agency, and other attributes.Data Storage & AccessData stored in existing applications can be accessed with specialized connectors. Integration and interoperability of these data sources is further enabled by the metadata repository that contains metamodels of the data contained in the sources, which then can be accessed and interchanged uniformly via the JMI API. These metamodels capture the essential structure and semantics of business components, allowing them to be accessed and queried via the JMI API or to be interchanged via XML. Through all of these processes, the J2EE infrastructure ensures the security and integrity of the data through transaction management and propagation and the underlying security architecture.To consolidate historical information for analysis of sales and marketing trends, a data warehouse is often the best solution. In this example, data can be extracted from the operational systems with a variety of Extract, Transform and Load tools (ETL). The metamodels allow EJBsdesigned for filtering, transformation, and consolidation of data to operate uniformly on datafrom diverse data sources as the bean is able to query the metamodel to identify and extract the pertinent fields. Queries and reports can be run against the data warehouse that contains information from numerous sources in a consistent, enterprise-wide fashion through the use of the JMI API (Mosher & Oh, 2007).Java in Industrial SettingsMany people know Java only as a tool on the World Wide Web that enables sites to perform some of their fancier functions such as interactivity and animation. However, the actual uses for Java are much more widespread. Since Java is an object-oriented language like C++, the time needed for application development is minimal. Java also encourages good software engineering practices with clear separation of interfaces and implementations as well as easy exception handling.In addition, Java's automatic memory management and lack of pointers remove some leading causes of programming errors. Most importantly, application developers do not need to create different versions of the software for different platforms. The advantages available through Java have even found their way into hardware. The emerging new Java devices are streamlined systems that exploit network servers for much of their processing power, storage, content, and administration.Benefits of JavaThe benefits of Java translate across many industries, and some are specific to the control and automation environment. For example, many plant-floor applications use relatively simple equipment; upgrading to PCs would be expensive and undesirable. Java's ability to run on any platform enables the organization to make use of the existing equipment while enhancing the application.IntegrationWith few exceptions, applications running on the factory floor were never intended to exchange information with systems in the executive office, but managers have recently discovered the need for that type of information. Before Java, that often meant bringing together data from systems written on different platforms in different languages at different times. Integration was usually done on a piecemeal basis, resulting in a system that, once it worked, was unique to the two applications it was tying together. Additional integration required developing a brand new system from scratch, raising the cost of integration.Java makes system integration relatively easy. Foxboro Controls Inc., for example, used Java to make its dynamic-performance-monitor software package Internet-ready. This software provides senior executives with strategic information about a plant's operation. The dynamic performance monitor takes data from instruments throughout the plant and performs variousmathematical and statistical calculations on them, resulting in information (usually financial) that a manager can more readily absorb and use.ScalabilityAnother benefit of Java in the industrial environment is its scalability. In a plant, embedded applications such as automated data collection and machine diagnostics provide critical data regarding production-line readiness or operation efficiency. These data form a critical ingredient for applications that examine the health of a production line or run. Users of these devices can take advantage of the benefits of Java without changing or upgrading hardware. For example, operations and maintenance personnel could carry a handheld, wireless, embedded-Java device anywhere in the plant to monitor production status or problems.Even when internal compatibility is not an issue, companies often face difficulties when suppliers with whom they share information have incompatible systems. This becomes more of a problem as supply-chain management takes on a more critical role which requires manufacturers to interact more with offshore suppliers and clients. The greatest efficiency comes when all systems can communicate with each other and share information seamlessly. Since Java is so ubiquitous, it often solves these problems (Paula, 1997).Dynamic Web Page DevelopmentJava has been used by both large and small organizations for a wide variety of applications beyond consumer oriented websites. Sandia, a multiprogram laboratory of the U.S. Department of Energy's National Nuclear Security Administration, has developed a unique Java application. The lab was tasked with developing an enterprise-wide inventory tracking and equipment maintenance system that provides dynamic Web pages. The developers selected Java Studio Enterprise 7 for the project because of its Application Framework technology and Web Graphical User Interface (GUI) components, which allow the system to be indexed by an expandable catalog. The flexibility, scalability, and portability of Java helped to reduce development timeand costs (Garcia, 2004)IssueJava Security for E-Business ApplicationsTo support the expansion of their computing boundaries, businesses have deployed Web application servers (WAS). A WAS differs from a traditional Web server because it provides a more flexible foundation for dynamic transactions and objects, partly through the exploitation of Java technology. Traditional Web servers remain constrained to servicing standard HTTP requests, returning the contents of static HTML pages and images or the output from executed Common Gateway Interface (CGI ) scripts.An administrator can configure a WAS with policies based on security specifications for Java servlets and manage authentication and authorization with Java Authentication andAuthorization Service (JAAS) modules. An authentication and authorization service can bewritten in Java code or interface to an existing authentication or authorization infrastructure. Fora cryptography-based security infrastructure, the security server may exploit the Java Cryptography Architecture (JCA) and Java Cryptography Extension (JCE). To present the user with a usable interaction with the WAS environment, the Web server can readily employ a formof "single sign-on" to avoid redundant authentication requests. A single sign-on preserves user authentication across multiple HTTP requests so that the user is not prompted many times for authentication data (i.e., user ID and password).Based on the security policies, JAAS can be employed to handle the authentication process with the identity of the Java client. After successful authentication, the WAS securitycollaborator consults with the security server. The WAS environment authentication requirements can be fairly complex. In a given deployment environment, all applications or solutions may not originate from the same vendor. In addition, these applications may be running on different operating systems. Although Java is often the language of choice for portability between platforms, it needs to marry its security features with those of the containing environment.Authentication & AuthorizationAuthentication and authorization are key elements in any secure information handling system. Since the inception of Java technology, much of the authentication and authorization issues have been with respect to downloadable code running in Web browsers. In many ways, this had been the correct set of issues to address, since the client's system needs to be protected from mobile code obtained from arbitrary sites on the Internet. As Java technology moved from a client-centric Web technology to a server-side scripting and integration technology, it required additional authentication and authorization technologies.The kind of proof required for authentication may depend on the security requirements of a particular computing resource or specific enterprise security policies. To provide such flexibility, the JAAS authentication framework is based on the concept of configurable authenticators. This architecture allows system administrators to configure, or plug in, the appropriate authenticatorsto meet the security requirements of the deployed application. The JAAS architecture also allows applications to remain independent from underlying authentication mechanisms. So, as new authenticators become available or as current authentication services are updated, system administrators can easily replace authenticators without having to modify or recompile existing applications.At the end of a successful authentication, a request is associated with a user in the WAS user registry. After a successful authentication, the WAS consults security policies to determine if the user has the required permissions to complete the requested action on the servlet. This policy canbe enforced using the WAS configuration (declarative security) or by the servlet itself (programmatic security), or a combination of both.The WAS environment pulls together many different technologies to service the enterprise. Because of the heterogeneous nature of the client and server entities, Java technology is a good choice for both administrators and developers. However, to service the diverse security needs of these entities and their tasks, many Java security technologies must be used, not only at a primary level between client and server entities, but also at a secondary level, from served objects. By using a synergistic mix of the various Java security technologies, administrators and developers can make not only their Web application servers secure, but their WAS environments secure as well (Koved, 2001).ConclusionOpen standards have driven the e-business revolution. As e-business continues to develop, various computing technologies help to drive its evolution. The Java programming language and platform have emerged as major technologies for performing e-business functions. Java programming standards have enabled portability of applications and the reuse of application components. Java uses many familiar concepts and constructs and allows portability by providing a common interface through an external Java Virtual Machine (JVM). Today, you can find Java technology in networks and devices that range from the Internet and scientific supercomputers to laptops and cell phones, from Wall Street market simulators to home game players and credit cards.Java has found a place on some of the most popular websites in the world. Java applications not only provide unique user interfaces, they also help to power the backend of websites. While Java technology has been used extensively for client side access and in the presentation layer, it is also emerging as a significant tool for developing scaleable server side programs.Since Java is an object-oriented language like C++, the time needed for application development is minimal. Java also encourages good software engineering practices with clear separation of interfaces and implementations as well as easy exception handling. Java's automatic memory management and lack of pointers remove some leading causes of programming errors. The advantages available through Java have also found their way into hardware. The emerging new Java devices are streamlined systems that exploit network servers for much of their processing power, storage, content, and administration.中文翻译:标题：Java的商业应用。

j2ee外文翻译文献

j2ee外文翻译Infrastructure for Automatic Dynamic DeploymentOf J2EE Application in Distributed EnvironmentsAnatoly Akkerman, Alexander Totok, and Vijay KaramchetiAbstract: in order to achieve such dynamic adaptation, we need an infrastructure for automating J2EE application deployment in such an environment. This need is quite evident to anyone who has ever tried deploying a J2EE application even on a single application server, which is a task that involves a great deal of configuration of both the system services and application components.Key words: j2ee; component; Distributed; Dynamic Deployment;1 IntroductionIn recent years, we have seen a significant growth in component-based enterprise application development. These applications are typically deployed on company Intranets or on the Internet and are characterized by high transaction volume, large numbers of users and wide area access. Traditionally they are deployed in a central location, using server clustering with load balancing (horizontal partitioning) to sustain user load. However, horizontal partitioning has been shown very efficient only in reducing application-related overheads of user-perceived response times, without having much effect on network-induced latencies. Vertical partitioning (e.g., running web tier and business tier in separate VMs) has been used for fault isolation and load balancing but it is sometimes impractical due to significant run-time overheads (even if one would keep the tiers on a fast local-area network) related to heavy use of remote invocations. Recent work [14] in the context of J2EE component based applications has shown viability of vertical partitioning in wide-area networks without incurring the aforementioned overheads. The key conclusions from that study can be summarized as follows:• Using properly designed applications, vertical distribution across wide-area networks improves user-perceived latencies.• Wide-area vertical layering requires replication of application components and maintaining consistency between replicas.• Additional replicas may be deployed dynamically to handle new requests.• Different replicas may, in fact, be different implementations of the same component based on usage (read-only, read-write).• New request paths may reus e components from previously deployed paths.Applying intelligent monitoring [6] and AI planning [2, 12] techniques in conjunction with the conclusions of that study, we see a potential for dynamic adaptation in industry-standard J2EE component-based applications in wide area networksThrough deployment of additional application components dynamically based on active monitoring. However, in order to achieve such dynamic adaptation, we need an infrastructure for automating J2EE application deployment in such an environment. This need is quite evident to anyone who has ever tried deploying a J2EE application even on a single application server, which is a task that involves a great deal of configuration of both the system services and application components. For example one has to set up JDBC data sources, messaging destinations and other resource adapters before application components can be configured and deployed. In a wide area deployment that spans multiple server nodes, this proves even more complex, since more system services that facilitate inter-node communications need to be configured and started and a variety of configuration data, like IP addresses, port numbers, JNDI names and others have to be consistently maintained in various configuration files on multiple nodes.This distributed deployment infrastructure must be able to:• address inter-component connectivity specification and define its effects on component configuration and deployment,• address application component dependencies on applicati on server services, their configuration and deployment,• provide simple but expressive abstractions to control adaptation through dynamic deployment and undeployment of components,• enable reuse of services and components to maintain efficient use of network nodes’ resources,• provide these facilities without incurring significant additional design effort on behalf of application programmers.In this paper we propose the infrastructure for automatic dynamic deployment of J2EE applications, which addresses all of the aforementioned issues. The infrastructure defines architecture description languages (ADL) for component and link description and assembly. The Component Description Language is used to describe application components and links. It provides clear separation of application components from system components. A flexible type system is used to define compatibility of component ports and links. A declaration and expression language for configurable component properties allows for specification of inter-component dependencies and propagation of properties between components. The Component (Replica) Assembly Language allows for assembly of replicas of previously defined components into application paths byConnecting appropriate ports via link replicas and specifying the mapping of these component replicas onto target application server nodes. The Component Configuration Process evaluates an application path’s correctness, identifies the dependenciesof application components on system components, and configures component replicas for deployment. An attempt is made to match and reuse any previously deployed replicas in the new path based on their configurations. We implement the infrastructure as a part of the JBoss open source Java application server [11] and test it on severalSample J2EE applications –Java Pets tore [23], Rubies [20] and TPC-W-NYU [32]. The infrastructure implementation utilizes the JBoss’s extendable micro-kernel architecture, based on the JMX [27] specification. Componentized architecture of JBoss allows incremental service deployments depending on the needs of deployed applications. We believe that dynamic reconfiguration of application servers through dynamic deployment and undeployment of system services is essential to building a resource-efficient framework for dynamic distributed deployment of J2EE applications. The rest of the paper is organized as follows. Section 2 provides necessary background for understanding the specifics of the J2EE component technology which are relevant to this study. Section 3 gives a general description of the infrastructure architecture, while section 4 goes deeper in describing particularly important and interesting internal mechanisms of the infrastructure. Section 5 describes the implementation of the framework, and related work is discussed in section 6.2 J2EE Background2.1 IntroductionComponent frameworks. A component framework is a middleware system that supports applications consisting of components conforming to certain standards. Application components are “plugged” into the component framework, which establishes their environmental conditions and regulates the interactions between them. This is usually done through containers, component holders, which also provide commonly required support for naming, security, transactions, and persistence. Component frameworks provide an integrated environment for component execution, as a result significantly reduce the effort .it takes to design, implement, deploy, and maintain applications. Current day industry component framework standards are represented by Object Management Group’s CORBA Component Model [18], Sun Microsystems’ Java 2 Platform Enterprise Edition (J2EE) [25] and Microsoft’s .NET [17], with J2EE being currently the most popular and wide ly used component framework in the enterprise arena.J2EE. Java 2 Platform Enterprise Edition (J2EE) [25] is a comprehensive standard for developing multi-tier enterprise Java applications. The J2EE specification among other things defines the following:• Component programming model,• Component contracts with the hosting server,• Services that the platform provides to these components,• Various human roles,• Compatibility test suites and compliance testing procedures.Among the list of services that a compliant application server must provide are messaging, transactions, naming and others that can be used by the application components. Application developed using J2EE adhere to the classical 3-Tier architectures –Presentation Tier, Business Tier, and Enterprise Information System (EIS) Tier (see Fig. 1). J2EE components belonging to each tier are developed adhering to theSpecific J2EE standards.1. Presentation or Web tier.This tier is actually subdivided into client and server sides. The client side hosts a web browser, applets and Java applications that communicate with the server side of presentationtier or the business tier. The server side hosts Java Servlet components [30], Java Server Pages (JSPs) [29] and static web content. These components are responsible for presenting business data to the end users. The data itself is typically acquired from the business tier and sometimes directly from the Enterprise Information System tier. The server side of the presentation tier is typically accessed through HTTP(S) protocol.2. Business or EJB tier.This tier consists of Enterprise Java Beans (EJBs) [24] that model the business logic of the enterprise application. These components provide persistence mechanisms and transactional support. The components in the EJB tier are invoked through remote invocations (RMI), in-JVM invocations or asynchronous message delivery, depending on the type of EJB component. The EJB specification defines several types of components. They differ in invocation style (synchronous vs. asynchronous, local vs. remote) and statefulness: completely stateless (e.g., Message-Driven Bean), stateful non-persistent(e.g., Stateful Session Bean), stateful persistent (e.g., Entity Bean). Synchronously invocable EJB components expose themselves through a special factory proxy object (an EJB Home object, which is specific to a given EJB), which is typically bound in JNDI by the deployer of the EJB. The EJB Home object allows creation or location of an EJBObject, which is a proxy to a particular instance of an EJB 1.3. Enterprise Information System (EIS) or Data tier.This tier refers to the enterprise information systems, like relational databases, ERP systems, messaging systems and the like. Business and presentation tier component communicate with this tier with the help of resource adapters as defined by the Java Connector Architecture [26].The J2EE programming model has been conceived as a distributed programming model where application components would run in J2EE servers and communicate with each other. After the initial introduction and first server implementations, the technology, most notably, the EJB technology has seen some a significant shift away from purely distributed computing model towards local interactions 2. There were very legitimate performance-related reasons behind this shift, however theDistributed features are still available. The J2EE specification has seen several revisions, the latest stable being version 1.3, while version 1.4 is going through last review phases 3. Weshall focus our attention on the former, while actually learning from the latter. Compliant commercial J2EE implementations are widely available from BEA Systems [4], IBM [9], Oracle [21] and other vendors. Several open source implementations, including JBoss [11] and JOnAS [19] claim compatibility as well. ARecent addition to the list is a new Apache project Geronimo [1].2.2 J2EE Component Programming ModelBefore we describe basic J2EE components, let’s first address the issue of defining what a component is a software component is a unit of composition with contractually specified interfaces and explicit context dependencies only. A software component can be deployed independently and is subject to composition by third parties [31].According to this definition the following entities which make up a typical J2EE application would be considered application components (some exceptions given below):• EJBs (session, entity, message-driven),• Web components (servlets, JSPs),• messaging destinations,• D ata sources,EJB and Web components are deployed into their corresponding containers provided by the application server vendor. They have well-defined contracts with their containers that govern lifecycle, threading, persistence and other concerns. Both Web and EJB components use JNDI lookups to locate resources or other EJB components they want to communicate with. The JNDI context in which these lookups are performed is maintained separately for each component by its container. Bindings messaging destinations, such as topics and queues, are resources provided by a messaging service implementation. Data sources are resources provided by the application server for data access by business components into the enterprise information services (data) tier, and most commonly are exemplified by JDBC connection pools managed by the applicationServer. A J2EE programmer explicitly programs only EJBs and Web components. These custom-written components interact with each other and system services both implicitly and explicitly. For example, an EJB developer may choose explicit transaction demarcation (i.e., Bean-Managed Transactions) which means that the developer assumes the burden of writingexplicit programmatic interaction with the platform’s Transaction Manager Service through well-defined interfaces. Alternatively, the developer may choose Container-Managed transaction demarcation, where transactional behavior of a component is defined through its descriptors and handled completely by the EJB container, thus acting as an implicit dependency of the EJB on the underlying Transaction Manager service.2.3 Links Between Components2.3.1 Remote InteractionsJ2EE defines only three basic inter-component connection types that can cross application server boundaries, in all three cases; communication is accomplished through special Java objects.• Remote EJB invocation: synchronous EJB invocations through EJB Home and EJB Object interfaces.• Java Connector outbound connection: synchronous message receipt, synchronous and asynchronous message sending,Database query using Connection Factory and Connection interfaces.• Java Connector inbound connection: asynchronous message delivery into Message-Driven Beans (MDBs) only, utilizing Activation Spec objects. In the first two cases, an application component developer writes the code that performs lookup of these objects in the component’s run-time JNDI context as well as code that issues method invocations or sends and receives messages to and from the remote component. The componen t’s run-time JNDI context is created for each deployment of the component.Bindings in the context are initialized at component deployment time by the deployed (usually by means of component’s deployment descriptors). These bindings are assumed to be static, since the specification does not provide any contract between the container and the component to inform of any binding changes In the case of Java Connector inbound communication, Activation Spec object lookup and all subsequent interactions with it are done implicitly by the MDB container. The protocol for lookup has not been standardized, though it is reasonable to assume a JMX- or JNDI-based lookup assuming the underlying application server provides facilities to control each step of deployment process, establishment of a link between J2EE components would involve:• Deployment of target component classes (optional for some components, like destinations),• C reation of a special Java object to be used as a target component’s proxy,• Binding of this ob ject with component’s host naming service (JNDI or JMX),• Start of the target component,• Deployment of referencing component classes,• Creation and population of referencing component’s run-time context in its host naming service,• start of the refere ncing component.However, none of modern application servers allow detailed control of the deployment process for all component types beyond what is possible by limited options in their deployment descriptors 4. Therefore our infrastructure will use a simplified approach that relies on features currently available on most application servers:• Ability to deploy messaging destinations and data sources dynamically,• Ability to create and bind into JNDI special objects to access messaging destinations and data sources,• Ability to specify initial binding of EJB Home objects upon EJB component deployment,• Ability to specify a JNDI reference 5 in the referencing component’s run-time context to point to the EJB Home binding of the referenced EJB component. In our infrastructure which is limited to homogeneous application servers, these options are sufficient to control intercomponent links through simple deployment descriptor manipulation. However, in context of heterogeneous application servers, simple JNDI references and thus simple descriptor manipulation are insufficient due to cross-application-serverClassloading issues.2.3.2 Local InteractionsSome interactions between components can occur only between components co-located in the same application server JVM and sometimes only in the same container. In the Web tier, examples of such interactions are servlet-to-servlet request forwarding. In the EJB tier, such interactions are CMP Entity relations and invocations via EJB local interfaces. Such local deployment concerns need not be exposed at the level of a distributed deployment infrastructure other than to ensure collocation. Therefore, the infrastructure treats allcomponents requiring collocation as a single component.2.4 Deployment of J2EE Applications and System Services2.4.1 Deployment of Application ComponentsDeployment and undeployment of standard J2EE components has not yet been standardized (see JSR 88 [10] for standardization effort 6). Therefore, each application server vendor provides proprietary facilities for component deployment and undeployment. And while the J2EE specification does define packaging of standard components which includes format and location of XML-based deployment descriptors within the package, this package is not required to be deployable by an application server without proprietary transformation. Examples of such transformation are• Generation of additional proprietary descriptors that supplement or replace the standard ones,• Code generation of application server-specific classes.In order to proceed with building a dynamic distributed deployment infrastructure capable of deploying in heterogeneous networks, we propose a universal unit of deployment to be a single XML-based deployment descriptor or a set of such,Bundled into an archive. The archive may optionally include Java classes that implement the component and any other resources that the component may need. Alternatively, the deployment descriptors may simply have URL references to codebases. We assume presence of a dynamic deployment/undeployment service on all compliant J2EE servers and a robust application server classloading architecture capable of repeated deployment cycles without undesired classloading-related issues. Most modern application servers (e.g., JBoss [11] and Geronimo [1]) do provide such facilities.2.4.2 Deployment of System Components (Services)While lacking only in the area of defining a clear specification of deployment and undeployment when it comes to application components, the J2EE standard falls much shorter with respect to system services. Not only a standardized deployment facility for system services is not specified, the specification, in fact, places no requirements even on life cycle properties of these services, nor does it address the issue of explicit specification of application component dependencies on the underlying system services. Instead it defines arole of human deploy who is responsible for ensuring that the required services are running based on his/her understanding of dependencies of application components on system services as implied by the nature of components and their deployment descriptors.References[1] Matt Bishop. Computer Security: Art and Science. New York, 2002[2] Matt Bishop. Vulnerabilities Analysis. Proceedings of the Second International Symposium on RecentAdvances in Intrusion Detection.Los Angeles 2006[3] Balasubra maniyan. An Architecture for Intrusion Detection using Autonomous Agents[M]. Department of Computer Sciences, Purdue University, 1998.。

计算机 JSP web 外文翻译外文文献

计算机 JSP web 外文翻译外文文献12.1 nEffective web n design involves separating business objects。

n。

and object XXX。

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XXX using JavaServer Pages。

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XXX of different architectures。

each building upon the us one。

The diagram below outlines this process。

and we will explain each component in detail later in this article.Note: XXX.)When Java Server Pages were introduced by Sun。

some people XXX。

While JSP is a key component of the J2EE n and serves as the preferred request handler and response mechanism。

it is XXX.XXX JSP。

the XXX that JSP is built on top of the servlet API and uses servlet XXX interesting ns。

such as whether we should XXX in our Web-enabled systems。

and if there is a way to combine servlets and JSPs。

外文文献-JSP Technology Conspectus And Specialties

外文文献-JSP Technology Conspectus And Specialties 毕业设计外文文献原文及译文学生姓名: 学号:电子与计算机科学技术系系别:网络工程专业:指导教师:2015年 5 月中北大学信息商务学院2015届毕业设计外文文献原文及译文JSP Technology Conspectus And SpecialtiesThe JSP (Java Server mix) technology is used by the Sun microsystem issued by the company to develop dynamic Web application technology. With its easy, cross-platform, in many dynamic Web application programming languages, in a short span of a few years, has formed a complete set of standards, and widely used in electronic commerce, etc. In China, the JSP now also got more extensive attention, get a good development, more and more dynamic website to JSP technology. Therelated technologies of JSP are briefly introduced.The JSP a simple technology can quickly and with the method of generating Web pages. Use the JSP technology Web page can be easily display dynamic content. The JSP technology are designed to make the construction based on Web applications easier and efficient, and these applications and various Web server, application server, the browser and development tools work together.The JSP technology isn't the only dynamic web technology, also not the first one, in the JSP technology existed before the emergence of several excellent dynamic web technology, such as CGI, ASP, etc. With the introduction of these technologies under dynamic web technology, the development and the JSP. TechnicalJSP the development background and development historyIn web brief history, from a world wide web that most of the network information static on stock transactions evolution to acquisition of an operation and infrastructure. In a variety of applications, may be used for based on Web client, look no restrictions.Based on the browser client applications than traditional based on client/server applications has several advantages. These benefits include almost no limit client access and extremely simplified application deployment and management (to update an application, management personnel only need to change the program on a server, not thousands of installation in client applications). So, the software industry is rapidly to build on the client browser multi-layer application.The rapid growth of exquisite based Web application requirements development of technical improvements. Static HTML to show relatively static content is right choice, The new challenge is to create the interaction based on Web applications, in these procedures, the content of a Web page is based on the user's request or the state of the system, and are not predefined characters.For the problem of an early solution is to use a CGI - BIN interface. Developers write to第 1 页共 19 页中北大学信息商务学院2015届毕业设计外文文献原文及译文interface with the relevant procedures and separate based on Web applications, the latter through the Web server to invoke the former. This plan has serious problem -- each new extensible CGI requirements in a new process on the server. If multiple concurrent users access to this procedure, these processes will use the Web server of all available resources, and the performance of the system will be reduced toextremely low.Some Web server providers have to provide for their server byplugins "and" the API to simplify the Web application development. These solutions are associated with certain Web server, cannot solve the span multiple suppliers solutions. For example, Microsoft's Active Server mix (ASP) technology in the Web page to create dynamic content more easily, but also can work in Microsoft on Personal Web Server and IIS.There are other solutions, but cannot make an ordinary pagedesigners can easily master. For example, such as the Servlet Java technologies can use Java language interaction application server code easier. Developers to write such Servlet to receive signals from the Web browser to generate an HTTP request, a dynamic response (may be inquires the database to finish the request), then send contain HTML or XML documents to the response of the browser.note: one is based on a Java Servlet Java technical operation in the server program (with different, the latter operating in the Applet browser end). In this book the Servlet chapter 4.Using this method, the entire page must have made in Java Servlet.If developers or Web managers want to adjust page, you'll have to edit and recompile the Servlet Java, even in logic has been able to run. Using this method, the dynamic content with the application of the page still need to develop skills.Obviously, what is needed is a industry to create dynamic content within the scope of the pages of the solution. This program will solve the current scheme are limited. As follows:can on any Web server or applications.will application page displays and separation.can rapidly developing and testing.simplify the interactive development based on Web application process.The JSP technology is designed to meet such requirements. The JSP specification is a Web server, application server, trading system and develop extensive cooperation between the tool suppliers. From this standard to develop the existing integration and balance of Java programming environment (for example, Java Servlet and JavaBeans) support techniques and tools. The result is a kind of new and developing method based on Web applications, using第 2 页共 19 页中北大学信息商务学院2015届毕业设计外文文献原文及译文component-based application logic page designers with powerful functions.Overall Semantics of a JSP PageA JSP page implementation class defines a _jspService() method mapping from the request to the response object. Some details of this transformation are specific to the scripting language used (see Chapter JSP.9, “Scripting”). Most details are not language specific and are described in this chapter.The content of a JSP page is devoted largely to describing the data that is written into the output stream of the response. (The JSP container usually sends this data back to the client.) The description is based on a JspWriter object that is exposed through the implicit object out (see Section JSP.1.8.3, “Implicit Objects”). Its value varies:Initially, out is a new JspWriter object. This object may bedifferent from the stream object returned from response.getWriter(), and may be considered to be interposed on the latter in order to implement buffering (see Section JSP.1.10.1, “The page Directive”). This is the initial out object. JSP page authors are prohibited from writingdirectly to either the PrintWriter or OutputStream associated with the ServletResponse.The JSP container should not invoke response.getWriter() until the time when the first portion of the content is to be sent to the client.This enables a number of uses of JSP, including using JSP as a language to “glue” actions that deliver binary content, or reliably forwarding to a servlet, or change dynamically the content type of the response before generating content. See Chapter JSP.4, “Internationalization Issues”.Within the body of some actions, out may be temporarily re-assigned to a different (nested) instance of a JspWriter object. Whether this is the case depends on the details of the action’s semantics. Typically the content of these temporary streams is appended to the stream previously referred to by out, and out is subsequently re-assignedto refer to the previous (nesting) stream. Such nested streams are always buffered, and require explicit flushing to a nesting stream or their contents will be discarded.If the initial out JspWriter object is buffered, then depending upon the value of the autoFlush attribute of the page directive, the content of that buffer will either be automatically flushed out to the ServletResponse output stream to obviate overflow, or an exception shall be thrown to signal buffer overflow. If the initial out JspWriter is unbuffered, then content written to it will be passed directly through to the ServletResponse output stream.A JSP page can also describe what should happen when some specific events occur. In JSP 2.1, the only events that can be described are the initialization and the destruction of the第 3 页共 19 页中北大学信息商务学院2015届毕业设计外文文献原文及译文page. These events are described using “well-known method names”in declaration elements..JavaScript is used for the first kind is browser, the dynamicgeneral purpose of client scripting language. Netscape first proposed in 1995, but its JavaScript LiveScript called. Then quickly Netscape LiveScript renamed JavaScript, Java developers with them from the same issued a statement. A statement Java and JavaScript will complement each other, but they are different, so the technology of the many dismissed the misunderstanding of the two technologies.JavaScript to create user interface control provides a scripting language. In fact, in the browser into the JavaScript code logic. It can support such effect: when the cursor on the Web page of a mobile user input validation or transform image.Microsoft also write out their JavaScript version and the JScript called. Microsoft and Netscape support JavaScript and JScript around a core characteristics and European Manufacturers is.md by (ECMA) standards organization, the control standard of scripting language. ECMA its scripting language ECMAScript named.Servlets and JSPs often include fragments of information that are common to an organization, such as logos, copyrights, trademarks, or navigation bars. The web application uses the include mechanisms to import the information wherever it is needed, since it is easier to change content in one place then to maintain it in every piece of codewhere it is used. Some of this information is static and either never or rarely changes, such as an organization's logo. In other cases, the information is more dynamic and changes often and unpredictably, such as a textual greeting that must be localized for each user. In both cases, you want to ensure that the servlet or JSP can evolve independently ofits included content, and that the implementation of the servlet or JSP properly updates its included content as necessary.You want to include a resource that does not change very much (suchas a page fragment that represents a header or footer) in a JSP. Use the include directive in the including JSP page, and give the included JSP segment a .jspf extension.You want to include content in a JSP each time it receives a request, rather than when the JSP is converted to a servlet. Use the jsp:include standard action.You want to include a file dynamically in a JSP, based on a value derived from a configuration file. Use the jsp:include standard action. Provide the value in an external properties file or as a configuration parameter in the deployment descriptor.You want to include a fragment of an XML file inside of a JSP document, or include a JSP page in XML syntax. Use the jsp:include standard action for the includes that you want to第 4 页共 19 页中北大学信息商务学院2015届毕业设计外文文献原文及译文occur with each request of the JSP. Use the jsp:directive.include element if the include action should occur during the translation phase.You want to include a JSP segment from outside the including file's context. Use the c:importThe operation principle and the advantages of JSP tagsIn this section of the operating principle of simple introductionJSP and strengths.For the first time in a JSP documents requested by the engine, JSP Servlet is transformed into a document JSP. This engine is itself a Servlet. The operating process of the JSP shown below:(1) the JSP engine put the JSP files converting a Java source files (Servlet), if you find the files have any grammar mistake JSP,conversion process will interrupt, and to the server and client output error messages.(2) if converted, with the engine JSP javac Java source filecompiler into a corresponding scale-up files.(3) to create a the Servlet (JSP page), the transformation of the Servlet jspInit () method was executed, jspInit () method in the life cycle of Servlet executed only once.(4) jspService () method invocation to the client requests. For each request, JSP engine to create a new thread for processing the request.If you have multiple clients and request the JSP files, JSP engine will create multiple threads. Each client requests a thread. To executemulti-thread can greatly reduce the requirement of system resources,improving the concurrency value and response time. But also should notice the multi-thread programming, due to the limited Servlet always in response to memory, so is very fast.(5) if the file has been modified. The JSP, server will be set according to the document to decide whether to recompile, if need to recompile, will replace the Servlet compile the memory and continue the process.(6) although the JSP efficiency is high, but at first when the need to convert and compile and some slight delay. In addition, if at any time due to reasons of system resources, JSP engine will in some way of uncertain Servlet will remove from memory. When this happens jspDestroy () method was first call.第 5 页共 19 页中北大学信息商务学院2015届毕业设计外文文献原文及译文(7) and then Servlet examples were marked with "add" garbage collection. But in jspInit () some initialization work, if establish connection with database, or to establish a network connection, from a configuration file take some parameters, such as, in jspDestory () release of the corresponding resources.Based on a Java language has many other techniques JSP page dynamic characteristics, technical have embodied in the following aspects: One simplicity and effectiveness:The JSP dynamic web pages with the compilation ofthe static HTML pages of writing is very similar. Just in theoriginal HTML page add JSP tags, or some of the proprietary scripting (this is not necessary). So, a familiar with HTML page write design personnel may be easily performed JSP page development. And the developers can not only, and write script by JSP tags used exclusively others have written parts to realize dynamic pages. So, an unfamiliar with the web developers scripting language, can use the JSP make beautiful dynamic pages. And this in other dynamic web development is impossible.Tow the independence of the program:The JSP are part of the familyof the API Java, ithas the general characteristics of the cross-platform Java program. In other words, is to have the procedure, namely the independence of the platform, 6 Write bided anywhere! .Three procedures compatibility:The dynamic content can various JSP form, so it canshow for all kinds of customers, namely from using HTML/DHTML browser to use various handheld wireless equipment WML (for example, mobile phones and pdas), personal digital equipment to use XML applications, all can use B2B JSP dynamic pages.Four program reusability:In the JSP page can not directly, but embedded scriptingdynamic interaction will be cited as a component part. So, once such a component to write, it can be repeated several procedures, the programof the reusability. Now, a lot of standard JavaBeans library is a good example.第 6 页共 19 页中北大学信息商务学院2015届毕业设计外文文献原文及译文JSP技术简介及特点JSP(Java Server Pages)技术是由Sun公司发布的用于开发动态Web应用的一项技术。

外文文献JSP中英文翻译

THE TECHNIQUE DEVELOPMENT HISTORY OF JSPBy:Kathy Sierra and Bert BatesSource:Servlet&JSPThe Java Server Pages( JSP) is a kind of according to web of the script plait distance technique, similar carries the script language of Java in the server of the Netscape company of server- side JavaScript( SSJS) and the Active Server Pages(ASP) of the Microsoft. JSP compares the SSJS and ASP to have better can expand sex, and it is no more exclusive than any factory or some one particular server of Web. Though the norm of JSP is to be draw up by the Sun company of, any factory can carry out the JSP on own system.The After Sun release the JSP( the Java Server Pages) formally, the this kind of new Web application development technique very quickly caused the people's concern. JSP provided a special development environment for the Web application that establishes the high dynamic state. According to the Sun parlance, the JSP can adapt to include the Apache WebServer, IIS4.0 on the market at inside of 85% server product.This chapter will introduce the related knowledge of JSP and Databases, and JavaBean related contents, is all certainly rougher introduction among them basic contents, say perhaps to is a Guide only, if the reader needs the more detailed information, pleasing the book of consult the homologous JSP.1.1 GENERALIZEThe JSP(Java Server Pages) is from the company of Sun Microsystems initiate, the many companies the participate to the build up the together of the a kind the of dynamic the state web the page technique standard, the it have the it in the construction the of the dynamic state the web page the strong but the do not the especially of the function. JSP and the technique of ASP of the Microsoft is very alike. Both all provide the ability that mixes with a certain procedure code and is explain by the language engine to carry out the procedure code in the code of HTML. Underneath we are simple of carry on the introduction to it.JSP pages are translated into servlets. So, fundamentally, any task JSP pages can perform could also be accomplished by servlets. However, this underlying equivalence does not mean that servlets and JSP pages are equally appropriate in all scenarios. The issue is not the power of the technology, it is the convenience, productivity, and maintainability of one or the other. After all, anything you can do on a particular computer platform in the Java programming language you could also do in assembly language. But it still matters which you choose.JSP provides the following benefits over servlets alone:• It is easier to write and maintain the HTML. Your static code is ordinary HTML: no extra backslashes, no double quotes, and no lurking Java syntax.• You can use standard Web-site development tools. Even HTML tools that know nothing about JSP can be used because they simply ignore the JSP tags.• You can divide up your development team. The Java programmers can work on the dynamic code. The Web developers can concentrate on the presentation layer. On large projects, this division is very important. Depending on the size of your team and the complexity of your project, you can enforce a weaker or stronger separation between the static HTML and the dynamic content.Now, this discussion is not to say that you should stop using servlets and use only JSP instead. By no means. Almost all projects will use both. For some requests in your project, you will use servlets. For others, you will use JSP. For still others, you will combine them with the MVC architecture . You want the appropriate tool for the job, and servlets, by themselves, do not complete your toolkit.1.2 SOURCE OF JSPThe technique of JSP of the company of Sun, making the page of Web develop the personnel can use the HTML perhaps marking of XML to design to turn the end page with format. Use the perhaps small script future life of marking of JSP becomes the dynamic state on the page contents.( the contents changes according to the claim of)The Java Servlet is a technical foundation of JSP, and the large Web applies the development of the procedure to need the Java Servlet to match with with the JSP and then can complete, this name of Servlet comes from the Applet, the local translation method of now is a lot of, this book in order not to misconstruction, decide the direct adoption Servlet but don't do any translation, if reader would like to, can call it as" small service procedure". The Servlet is similar to traditional CGI, ISAPI, NSAPI etc. Web procedure development the function of the tool in fact, at use the Java Servlet hereafter, the customer need not use again the lowly method of CGI of efficiency, also need not use only the ability come to born page of Web of dynamic state in the method of API that a certain fixed Web server terrace circulate. Many servers of Web all support the Servlet, even not support the Servlet server of Web directly and can also pass the additional applied server and the mold pieces to support the Servlet. Receive benefit in the characteristic of the Java cross-platform, the Servlet is also a terrace irrelevant, actually, as long as match the norm of Java Servlet, the Servlet is complete to have nothing to do with terrace and is to have nothing to do with server of Web. Because the Java Servlet is internal to provide the service by the line distance, need not start a progressto the each claimses, and make use of the multi-threading mechanism can at the same time for several claim service, therefore the efficiency of Java Servlet is very high.But the Java Servlet also is not to has no weakness, similar to traditional CGI, ISAPI, the NSAPI method, the Java Servlet is to make use of to output the HTML language sentence to carry out the dynamic state web page of, if develop the whole website with the Java Servlet, the integration process of the dynamic state part and the static state page is an evil-foreboding dream simply. For solving this kind of weakness of the Java Servlet, the SUN released the JSP.A number of years ago, Marty was invited to attend a small 20-person industry roundtable discussion on software technology. Sitting in the seat next to Marty was James Gosling, inventor of the Java programming language. Sitting several seats away was a high-level manager from a very large software company in Redmond, Washington. During the discussion, the moderator brought up the subject of Jini, which at that time was a new Java technology. The moderator asked the manager what he thought of it, and the manager responded that it was too early to tell, but that it seemed to be an excellent idea. He went on to say that they would keep an eye on it, and if it seemed to be catching on, they would follow his company's usual "embrace and extend" strategy. At this point, Gosling lightheartedly interjected "You mean disgrace and distend."Now, the grievance that Gosling was airing was that he felt that this company would take technology from other companies and suborn it for their own purposes. But guess what? The shoe is on the other foot here. The Java community did not invent the idea of designing pages as a mixture of static HTML and dynamic code marked with special tags. For example, Cold Fusion did it years earlier. Even ASP (a product from the very software company of the aforementioned manager) popularized this approach before JSP came along and decided to jump on the bandwagon. In fact, JSP not only adopted the general idea, it even used many of the same special tags as ASP did.The JSP is an establishment at the model of Java servlets on of the expression layer technique, it makes the plait write the HTML to become more simple.Be like the SSJS, it also allows you carry the static state HTML contents and servers the script mix to put together the born dynamic state exportation. JSP the script language that the Java is the tacit approval, however, be like the ASP and can use other languages( such as JavaScript and VBScript), the norm of JSP also allows to use other languages.1.3JSP CHARACTERISTICSIs a service according to the script language in some one language of the statures system this kind of discuss, the JSP should be see make is a kind of script language.However, be a kind of script language, the JSP seemed to be too strong again, almost can use all Javas in the JSP.Be a kind of according to text originally of, take manifestation as the central development technique, the JSP provided all advantages of the Java Servlet, and, when combine with a JavaBeans together, providing a kind of make contents and manifestation that simple way that logic separate. Separate the contents and advantage of logical manifestations is, the personnel who renews the page external appearance need not know the code of Java, and renew the JavaBeans personnel also need not be design the web page of expert in hand, can use to take the page of JavaBeans JSP to define the template of Web, to build up a from have the alike external appearance of the website that page constitute. JavaBeans completes the data to provide, having no code of Java in the template thus, this means that these templates can be written the personnel by a HTML plait to support. Certainly, can also make use of the Java Servlet to control the logic of the website, adjust through the Java Servlet to use the way of the document of JSP to separate website of logic and contents.Generally speaking, in actual engine of JSP, the page of JSP is the edit and translate type while carry out, not explain the type of. Explain the dynamic state web page development tool of the type, such as ASP, PHP3 etc., because speed etc. reason, have already can't satisfy current the large electronic commerce needs appliedly, traditional development techniques are all at to edit and translate the executive way change, such as the ASP → ASP+;PHP3 → PHP4.In the JSP norm book, did not request the procedure in the JSP code part( be called the Scriptlet) and must write with the Java definitely. Actually, have some engines of JSP are adoptive other script languages such as the EMAC- Script, etc., but actually this a few script languages also are to set up on the Java, edit and translate for the Servlet to carry out of. Write according to the norm of JSP, have no Scriptlet of relation with Java also is can of, however, mainly lie in the ability and JavaBeans, the Enterprise JavaBeanses because of the JSP strong function to work together, so even is the Scriptlet part not to use the Java, edit and translate of performance code also should is related with Java.1.4JSP MECHANISMTo comprehend the JSP how unite the technical advantage that above various speak of, come to carry out various result easily, the customer must understand the differentiation of" the module develops for the web page of the center" and" the page develops for the web page of the center" first.The SSJS and ASP are all in several year ago to release, the network of that time is still very young, no one knows to still have in addition to making all business, datas and theexpression logic enter the original web page entirely heap what better solve the method. This kind of model that take page as the center studies and gets the very fast development easily. However, along with change of time, the people know that this kind of method is unwell in set up large, the Web that can upgrade applies the procedure. The expression logic write in the script environment was lock in the page, only passing to shear to slice and glue to stick then can drive heavy use. Express the logic to usually mix together with business and the data logics, when this makes be the procedure member to try to change an external appearance that applies the procedure but do not want to break with its llied business logic, apply the procedure of maintenance be like to walk the similar difficulty on the eggshell. In fact in the business enterprise, heavy use the application of the module already through very mature, no one would like to rewrite those logics for their applied procedure.HTML and sketch the designer handed over to the implement work of their design the Web plait the one who write, make they have to double work- Usually is the handicraft plait to write, because have no fit tool and can carry the script and the HTML contents knot to the server to put together. Chien but speech, apply the complexity of the procedure along with the Web to promote continuously, the development method that take page as the center limits sex to become to get up obviously.At the same time, the people always at look for the better method of build up the Web application procedure, the module spreads in customer's machine/ server the realm. JavaBeans and ActiveX were published the company to expand to apply the procedure developer for Java and Windows to use to come to develop the complicated procedure quickly by" the fast application procedure development"( RAD) tool. These techniques make the expert in the some realm be able to write the module for the perpendicular application plait in the skill area, but the developer can go fetch the usage directly but need not control the expertise of this realm.Be a kind of take module as the central development terrace, the JSP appeared. It with the JavaBeans and Enterprise JavaBeans( EJB) module includes the model of the business and the data logic for foundation, provide a great deal of label and a script terraces to use to come to show in the HTML page from the contents of JavaBeans creation or send a present in return. Because of the property that regards the module as the center of the JSP, it can drive Java and not the developer of Java uses equally. Not the developer of Java can pass the JSP label( Tags) to use the JavaBeans that the deluxe developer of Java establish. The developer of Java not only can establish and use the JavaBeans, but also can use the language of Java to come to control more accurately in the JSP page according to the expression logic of the first floor JavaBeans.See now how JSP is handle claim of HTTP. In basic claim model, a claim directly was send to JSP page in. The code of JSP controls to carry on hour of the logic processing and module of JavaBeanses' hand over with each other, and the manifestation result in dynamic state bornly, mixing with the HTML page of the static state HTML code. The Beans can be JavaBeans or module of EJBs. Moreover, the more complicated claim model can see make from is request other JSP pages of the page call sign or Java Servlets.The engine of JSP wants to chase the code of Java that the label of JSP, code of Java in the JSP page even all converts into the big piece together with the static state HTML contents actually. These codes piece was organized the Java Servlet that customer can not see to go to by the engine of JSP, then the Servlet edits and translate them automatically byte code of Java.Thus, the visitant that is the website requests a JSP page, under the condition of it is not knowing, an already born, the Servlet actual full general that prepared to edit and translate completes all works, very concealment but again and efficiently. The Servlet is to edit and translate of, so the code of JSP in the web page does not need when the every time requests that page is explain. The engine of JSP need to be edit and translate after Servlet the code end is modify only once, then this Servlet that editted and translate can be carry out. The in view of the fact JSP engine auto is born to edit and translate the Servlet also, need not procedure member begins to edit and translate the code, so the JSP can bring vivid sex that function and fast developments need that you are efficiently.Compared with the traditional CGI, the JSP has the equal advantage. First, on the speed, the traditional procedure of CGI needs to use the standard importation of the system to output the equipments to carry out the dynamic state web page born, but the JSP is direct is mutually the connection with server. And say for the CGI, each interview needs to add to add a progress to handle, the progress build up and destroy by burning constantly and will be a not small burden for calculator of be the server of Web. The next in order, the JSP is specialized to develop but design for the Web of, its purpose is for building up according to the Web applied procedure, included the norm and the tool of a the whole set. Use the technique of JSP can combine a lot of JSP pages to become a Web application procedure very expediently.JSP的技术发展历史作者：Kathy Sierra and Bert Bates来源：Servlet&JSPJava Server Pages(JSP)是一种基于web的脚本编程技术，类似于网景公司的服务器端Java脚本语言——server-side JavaScript(SSJS)和微软的Active Server Pages(ASP)。

基于J2EE在分布式环境下的底层结构的自动动态配置的应用-外文翻译

Infrastructure for Automatic DynamicDeployment Of J2EE Application inDistributed EnvironmentsAnatoly Akkerman, Alexander Totok, and Vijay Karamcheti1. IntroductionIn recent years, we have seen a significant growth in component-based enterprise application development. These applications are typically deployed on company Intranets or on the Internet and are characterized by high transaction volume, large numbers of users and wide area access. Traditionally they are deployed in a central location, using server clustering with load balancing (horizontal partitioning) to sustain user load. However, horizontal partitioning has been shown very efficient only in reducing application-related overheads of user-perceived response times, without having much effect on network-induced latencies. Vertical partitioning (e.g., running web tier and business tier in separate VMs) has been used for fault isolation and load balancing but it is sometimes impractical due to significant run-time overheads (even if one would keep the tiers on a fast local-area network) related to heavy use of remote invocations. Recent work in the context of J2EE component based applications has shown viability of vertical partitioning in wide-area networks without incurring the aforementioned overheads. The key conclusions from that study can be summarized as follows:• Using properly designed applications, vertical distribution across wide-area networks improves user-perceived latencies.• Wide-area vertical layering requires replication of application components and maintaining consistency between replicas.• Additional replicas may be deployed dynamically to handle new requests.• Different replicas may, in fact, be different implementations of the same component based on usage (read-only, read-write).• New request paths may reuse components from previously deployed paths.Applying intelligent monitoring and AI planning techniques in conjunction with the conclusions of that study, we see a potential for dynamic adaptation in industry-standard J2EE component-based applications in wide area networksThrough deployment of additional application components dynamically based on active monitoring. However, in order to achieve such dynamic adaptation, we need an infrastructure for automating J2EE application deployment in such an environment. This need is quite evident to anyone who has ever tried deploying a J2EE application even on a single application server, which is a task that involves a great deal of configuration of both the system services and application components. For example one has to set up JDBC data sources, messaging destinations and other resource adapters before application components can be configured and deployed. In a wide area deployment that spans multiple server nodes, this proves even more complex, since more system services that facilitate inter-node communications need to be configured and started and a variety of configuration data, like IP addresses, port numbers, JNDI names and others have to be consistently maintained in various configuration files on multiple nodes.This distributed deployment infrastructure must be able to:• address inter-component connectivity specification and define its effects on component configuration and deployment,• address application component dependencies on application server services, their configuration and deployment,• provide simple but expressive abstractions to control adaptation through dynamic deployment and undeployment of components,• enable reuse of services and components to maintain efficient use of network nodes’ resources,• provide these facilities without incurring significant additional design effort on behalf of application programmers.In this paper we propose the infrastructure for automatic dynamic deployment of J2EE applications, which addresses all of the aforementioned issues. The infrastructuredefines architecture description languages (ADL) for component and link description and assembly. The Component Description Language is used to describe application components and links. It provides clear separation of application components from system components. A flexible type system is used to define compatibility of component ports and links. A declaration and expression language for configurable component properties allows for specification of inter-component dependencies and propagation of properties between components. The Component (Replica) Assembly Language allows for assembly of replicas of previously defined components into application paths by connecting appropriate ports via link replicas and specifying the mapping of these component replicas onto target application server nodes. The Component Configuration Process evaluates an application path’s correctness, identifies the dependenciesof application components on system components, and configures component replicas for deployment. An attempt is made to match and reuse any previously deployed replicas in the new path based on their configurations. We implement the infrastructure as a part of the JBoss open source Java application server and test it on several technology sample J2EE applications –Java Pets tore, Rubies and TPC-W-NYU . The infrastructure implementation utilizes the JBoss’s extendable micro-kernel architecture, based on the JMX specification. Componentized architecture of JBoss allows incremental service deployments depending on the needs of deployed applications. We believe that dynamic reconfiguration of application servers through dynamic deployment and undeployment of system services is essential to building a resource-efficient framework for dynamic distributed deployment of J2EE applications. The rest of the paper is organized as follows. Section 2 provides necessary background for understanding the specifics of the J2EE component technology which are relevant to this study. Section 3 gives a general description of the infrastructure architecture, while section 4 goes deeper in describing particularly important and interesting internal mechanisms of the infrastructure. Section 5 describes the implementation of the framework, and related work is discussed in section 6.2. J2EE Background2.1 IntroductionComponent frameworks.A component framework is a middleware system that supports applications consisting of components conforming to certain standards. Application components are “plugged” into the component framework, which establishes their environmental conditions and regulates the interactions between them. This is usually done through containers, component holders, which also provide commonly required support for naming, security, transactions, and persistence. Component frameworks provide an integrated environment for component execution, as a result significantly reduce the effort .it takes to design, implement, deploy, and maintain applications. Current day industry component framework standards are represented by Object Management Group’s CORBA Component Model, Sun Microsystems’ Java 2 Platform Enterprise Edition (J2EE) and Microsoft’s .NET, with J2EE being currently the most popular and widely used component framework in the enterprise arena.J2EE.Java 2 Platform Enterprise Edition (J2EE) is a comprehensive standard for developing multi-tier enterprise Java applications. The J2EE specification among other things defines the following:• Compon ent programming model,• Component contracts with the hosting server,• Services that the platform provides to these components,• Various human roles,• Compatibility test suites and compliance testing procedures.Among the list of services that a compliant application server must provide are messaging, transactions, naming and others that can be used by the application components. Application developed using J2EE adhere to the classical 3-Tier architectures – Presentation Tier, Business Tier, and Enterprise Information System (EIS)Tier (see Fig. 1). J2EE components belonging to each tier are developed adhering to the Specific J2EE standards.1. Presentation or Web tier.This tier is actually subdivided into client and server sides. The client side hosts a web browser, applets and Java applications that communicate with the server side of presentation tier or the business tier. The server side hosts Java Servlet components, Java Server Pages (JSPs) and static web content. These components are responsible for presenting business data to the end users. The data itself is typically acquired from the business tier and sometimes directly from the Enterprise Information System tier. The server side of the presentation tier is typically accessed through HTTP(S) protocol.2. Business or EJB tier.This tier consists of Enterprise Java Beans (EJBs) that model the business logic of the enterprise application. These components provide persistence mechanisms and transactional support. The components in the EJB tier are invoked through remote invocations (RMI), in-JVM invocations or asynchronous message delivery, depending on the type of EJB component. The EJB specification defines several types of components. They differ in invocation style (synchronous vs. asynchronous, local vs. remote) and statefulness: completely stateless (e.g., Message-Driven Bean), stateful non-persistent (e.g., Stateful Session Bean), stateful persistent (e.g., Entity Bean). Synchronously invocable EJB components expose themselves through a special factory proxy object (an EJB Home object, which is specific to a given EJB), which is typically bound in JNDI by the deployer of the EJB. The EJB Home object allows creation or location of an EJB Object, which is a proxy to a particular instance of an EJB 1.3. Enterprise Information System (EIS) or Data tier.This tier refers to the enterprise information systems, like relational databases, ERP systems, messaging systems and the like. Business and presentation tier component communicate with this tier with the help of resource adapters as defined by the Java Connector Architecture. The J2EE programming model has been conceived as adistributed programming model where application components would run in J2EE servers and communicate with each other. After the initial introduction and first server implementations, the technology, most notably, the EJB technology has seen some a significant shift away from purely distributed computing model towards local interactions There were very legitimate performance-related reasons behind this shift, however the Distributed features are still available. The J2EE specification has seen several revisions, the latest stable being version 1.3, while version 1.4 is going through last review phases 3. We shall focus our attention on the former, while actually learning from the latter. Compliant commercial J2EE implementations are widely available from BEA Systems , IBM, Oracle and other vendors. Several open source implementations, including JBoss and JOnAS claim compatibility as well. A Recent addition to the list is a new Apache project Geronimo.2.2 J2EE Component Programming ModelBefore we describe basic J2EE components, let’s first address the issue of defining what a component is a software component is a unit of composition with contractually specified interfaces and explicit context dependencies only. A software component can be deployed independently and is subject to composition by third parties.According to this definition the following entities which make up a typical J2EE application would be considered application components (some exceptions given below):• EJBs (session, entity, message-driven),• Web components (servlets, JSPs),• messaging destinations,• Data sources,EJB and Web components are deployed into their corresponding containers provided by the application server vendor. They have well-defined contracts with their containers that govern lifecycle, threading, persistence and other concerns. Both Web and EJB components use JNDI lookups to locate resources or other EJB components they want to communicate with. The JNDI context in which these lookups are performed is maintainedseparately for each component by its container. Bindings messaging destinations, such as topics and queues, are resources provided by a messaging service implementation. Data sources are resources provided by the application server for data access by business components into the enterprise information services (data) tier, and most commonly are exemplified by JDBC connection pools managed by the applicationServer.A J2EE programmer explicitly programs only EJBs and Web components. These custom-written components interact with each other and system services both implicitly and explicitly. For example, an EJB developer may choose explicit transaction demarcation (i.e., Bean-Managed Transactions) which means that the developer assumes the burden of writing explicit programmatic interaction with the platform’s Transaction Manager Service through well-defined interfaces. Alternatively, the developer may choose Container-Managed transaction demarcation, where transactional behavior of a component is defined through its descriptors and handled completely by the EJB container, thus acting as an implicit dependency of the EJB on the underlying Transaction Manager service.2.3 Links Between Components2.3.1 Remote InteractionsJ2EE defines only three basic inter-component connection types that can cross application server boundaries, in all three cases; communication is accomplished through special Java objects.•Remote EJB invocation: synchronous EJB invocations through EJB Home and EJB Object interfaces.• Java Connector outbound connection: synchronous message receipt, synchronous and asynchronous message sending,Database query using Connection Factory and Connection interfaces.• Java Connector inbound connection: asynchronous message delivery into Message-Driven Beans (MDBs) only, utilizing Activation Spec objects. In the first two cases, an application component developer writes the code that performs lookup of theseobjects in the component’s run-time JNDI context as well as code that issues method invocations or sends and receives messages to and from the remote component. The component’s run-time JNDI context is created for each deployment of the component. Bindings in the context are initialized at component deployment time by the deployed (usually by means of component’s deployment descriptors). These bindings are assumed to be static, since the specification does not provide any contract between the container and the component to inform of any binding changes In the case of Java Connector inbound communication, Activation Spec object lookup and all subsequent interactions with it are done implicitly by the MDB container. The protocol for lookup has not been standardized, though it is reasonable to assume a JMX- or JNDI-based lookup assuming the underlying application server provides facilities to control each step of deployment process, establishment of a link between J2EE components would involve:• Deployment of target component classes (optional for some components, like destinations),• C reation of a special Java object to be used as a target component’s proxy,• B inding of this object with component’s host naming service (JNDI or JMX),• Start of the target component,• Deployment of referencing component classes,• Creation and population of referencing component’s run-time context in its host naming service,• start of the referencing component.However, none of modern application servers allow detailed control of the deployment process for all component types beyond what is possible by limited options in their deployment descriptors 4. Therefore our infrastructure will use a simplified approach that relies on features currently available on most application servers:• Ability to deploy messaging destinations and data sources dynamically,• Ability to create and bind into JNDI special objects to access messaging destinations and data sources,• Ability to specify initial binding of EJB Home objects upon EJB component deployment,• Ability to specify a JNDI reference 5 in the referencing component’s run-time context to point to the EJB Home binding of the referenced EJB component. In our infrastructure which is limited to homogeneous application servers, these options are sufficient to control intercomponent links through simple deployment descriptor manipulation. However, in context of heterogeneous application servers, simple JNDI references and thus simple descriptor manipulation are insufficient due to cross-application-server Classloading issues.2.3.2 Local InteractionsSome interactions between components can occur only between components co-located in the same application server JVM and sometimes only in the same container. In the Web tier, examples of such interactions are servlet-to-servlet request forwarding. In the EJB tier, such interactions are CMP Entity relations and invocations via EJB local interfaces. Such local deployment concerns need not be exposed at the level of a distributed deployment infrastructure other than to ensure collocation. Therefore, the infrastructure treats all components requiring collocation as a single component.2.4 Deployment of J2EE Applications and System Services2.4.1 Deployment of Application ComponentsDeployment and undeployment of standard J2EE components has not yet been standardized (see JSR 88 [10] for standardization effort 6). Therefore, each application server vendor provides proprietary facilities for component deployment and undeployment. And while the J2EE specification does define packaging of standard components which includes format and location of XML-based deployment descriptors within the package, this package is not required to be deployable by an application server without proprietary transformation. Examples of such transformation are• Generation of additional proprietary descriptors that supplement or replace the standard ones,• Code generation of application server-specific classes.In order to proceed with building a dynamic distributed deployment infrastructure capable of deploying in heterogeneous networks, we propose a universal unit of deployment to be a single XML-based deployment descriptor or a set of such,Bundled into an archive. The archive may optionally include Java classes that implement the component and any other resources that the component may need. Alternatively, the deployment descriptors may simply have URL references to codebases. We assume presence of a dynamic deployment/undeployment service on all compliant J2EE servers and a robust application server classloading architecture capable of repeated deployment cycles without undesired classloading-related issues. Most modern application servers(e.g., JBoss and Geronimo) do provide such facilities.2.4.2 Deployment of System Components (Services)While lacking only in the area of defining a clear specification of deployment and undeployment when it comes to application components, the J2EE standard falls much shorter with respect to system services. Not only a standardized deployment facility for system services is not specified, the specification, in fact, places no requirements even on life cycle properties of these services, nor does it address the issue of explicit specification of application component dependencies on the underlying system services. Instead it defines a role of human deploy who is responsible for ensuring that the required services are running based on his/her understanding of dependencies of application components on system services as implied by the nature of components and their deployment descriptors.基于J2EE在分布式环境下的底层结构的自动动态配置的应用Anatoly Akkerman, Alexander Totok, and Vijay Karamcheti1. 前言近几年，我们已经看到基于组件的企业应用开发的显著增加。

Java、J2ee的Spring框架和大数据技术外文文献翻译

文献信息文献标题：Implementing and Analyzing Big Data Techniques with Spring Frame Work in Java & J2EE Based Application（基于Java/J2EE的Spring 框架实现和分析大数据技术）文献作者及出处：Saxena A, Kaushik N, Kaushik N. Implementing and Analyzing Big Data Techniques with Spring Frame Work in Java & J2EE Based Application[C]//Proceedings of the Second International Conference on Information and Communication Technology for Competitive Strategies. ACM, 2016:5.字数统计：英文2814单词，15570字符；中文4912汉字外文文献Implementing and Analyzing Big Data Techniques withSpring Frame Work in Java & J2EE Based ApplicationAbstract –In the time of big data techniques with spring framework on java, web servers or application server as the significant channel in big data should be updated to meet execution and force imperatives. Significant endeavors have been put resources into web server or application server conveyance and web storing procedures, but very few efforts have been paid to improve hardware-favored web type services. Big Data with spring framework in java is a promising business and computing model in web framework. Spring is the most popular open source Java application Framework. It combines all the industry-standard frameworks (for e.g. Struts and Hibernate) and approaches into one bundle. The expense and working costs of data centers have skyrocketed with the increase in computing capacity. Big data is a concept that defines the large volume of both structured and unstructured data – that inundates a business on a day-to-day environment. This research argues the need to provide novel method and tools to bolster programming engineers meaning toenhance vitality productivity and minimize the subsequent from outlining, creating, sending and running programming in Big Data with spring framework.Keywords –Java, J2ee, Hadoop Framework, spring, Big Data.I.INTRODUCTIONBig Data with spring framework based applications and innovation components are composed in java& J2ee. Java has inherent limitations that can keep endeavors from advancing execution and using vast in memory data sets. Organizations endeavor to work around these dormancy, versatility and memory size issues by utilizing separate caching frameworks or analyzing a subset of accessible data. Then again, this influences the quality and convenience of business choices and even lessens revenue.Objective of big data:•By giving a semantic end-to-end connection between clients and data sources.•Enabling clients to quickly define instinctive queries utilizing natural vocabularies and conceptualizations.•Seamlessly coordinating information spread over various distributed data sources, including streaming sources.•Exploiting gigantic parallelism for adaptability a long ways past traditional RDBMSs and along these lines lessening the turnaround time for information requests to minutes as opposed.Objectives for Spring Framework:•The potential favorable circumstances of utilizing Spring's dependency injection.•Dependency injection in XML, utilizing constructor.•Default scope for Spring beans.•How to declare an initialization method in a Spring bean.Java:Java is one of the most robust, mainly used and perfect programming languagefor creating enterprise applications. Over the years, Java development has evolved from applets run on a web browser (chrome, mozila) to large enterprise distributed applications run on multiple servers. Presently, Java has three different flavors, and each addresses certain programming requirements.Spring framework is the most well known application advancement structure for big business Java. A great many designers around the globe use Spring Framework to make high performing, effortlessly testable, reusable code.J2ee:J2ee utilizes a multi-level circulated application model. There are three levels in the commonplace J2EE application model: presentation tier, business logic tier and data tier.Framework:The framework is intended to streamline the full improvement cycle, from building, to sending, to looking after applications. it can be considered as an arrangement of capacities helping the designers in making the applications.II.Spring FrameworkSpring is a lightweight framework. It can be considered as a structure of systems in light of the fact that it gives backing to different structures, for example, Struts, Hibernate, Tapestry, EJB, JSF and so forth. The system, in more extensive sense, can be characterized as a structure where we discover arrangement of the different specialized issues.Features of SpringFramework:•Lightweight -Spring is lightweight as far as size and overhead. The whole spring system can be conveyed in a Jar file that weighs in at a little more than 1 MB.•Aspect-Oriented - Spring supports the features of aspect oriented programming approach that enables cohesive development.•Container -Spring is a compartment in light of the fact that it deals with the life cycle and configuration of application objects.•Framework -Spring accompanies MVC web application framework, based on core Spring functionality. This structure is profoundly configurable by means of methodology interfaces, and obliges various perspective innovations like JSP, Speed, Tiles.Aspect oriented programming:To permit clients to actualize custom perspectives, supplementing their utilization of OOP with AOP. Aspect oriented programming is regularly characterized as a programming strategy that advances partition of worries inside of a software framework. Frameworks are made out of a few parts, each in charge of a particular bit of usefulness.AOP gives you perspectives. Aspects empower modularization of concerns, for example, transaction management that cut across multiple types and objects.AOP is utilized as a part of theSpring Framework:•To give definitivedeclarative enterprise services, particularly as a substitution for EJB explanatory services. The most critical such service is explanatory transaction management.•To permit clients to actualize custom aspects, complementing their utilization of OOP with AOP.Inversion of Control:The IoC (Inversion of Control) pattern utilizes three diverse methodologies as a part of request to accomplish decoupling of control of services from your components:•Interface Injection : Your components expressly fit in with an arrangement of interfaces, with related setup metadata, keeping in mind the end goal to permit the system to oversee them accurately.•Setter Injection : External metadata is utilized to arrange how your segments can be cooperated with.•Constructor Injection: Your components are enrolled with the framework, including the parameters to be utilized when thecomponents are developed, and the structure gives instances of the component with the majority of the predeterminedfacilities applied.Dependency Injection:Dependency Injection (DI) is a design pattern that expels the dependency from the programming code with the goal that it can be anything but difficult to oversee and test the application. Dependency Injection makes our programming code inexactly coupled.III.Big DataBig Data is more and various types of data than is effectively taken care of traditional relational database management systems (RDBMSs). Another helpful point of view is to describe big data as having high volume, high speed, and high assortment.•High volume: the sum or amount of data.•High speed: the rate at which data is created.•High assortment: the distinctive sorts of data.Big Data is a technique that is utilized to portray data that is high volume and speed,requires new technologies and systems to catch, store, and analyze it; and is utilized to upgrade decision making, give understanding and disclosure, and bolster and advance technique. Normally, to analyze data, individuals used to make diverse data sets in view of one or more regular fields so examination turns out to be simple. Big data has numerous sources. For instance, each mouse event on a site can be caught in Web log files and examined keeping in mind the end goal to better comprehend customers' purchasing practices and to impact their shopping by powerfully suggesting products. Social media sources, for example, Facebook and Twitter create enormous measures of remarks and tweets. This data can be caught and broke down to comprehend, for instance, what individuals consider new item presentations. Machines, for example, savvy meters, produce data. These meters persistently stream information about power, water, or gas utilization that can be imparted to clients and consolidated with estimating arrangements to rouse clients to move some of their vitality utilization.Figure 1. Information flow of Big DataThis Figure 1shows different phases of Big Data Uses of Big Data.1.Fraud detection:In many cases, fraud is discovered long after the fact, and soon thereafter the harm has been done and all that is left is to minimize the harm and modify arrangements to keep it from happening once more. Big Data stages that can examine cases and exchanges continuously, recognizing huge scale designs crosswise over numerous exchanges or identifying abnormal conduct from an individual client, can change the fraud detection game.2.IT log analytics:IT arrangements and IT divisions create a colossal amount of logs and follow information. Without a Big Data arrangement, quite a bit of this information must go unexamined.3.Call center analyticsBig Data arrangements can distinguish repeating issues or client and staff conduct designs on the fly not just by comprehending time/quality determination measurements, additionally by catching and preparing call content itself.4.Social media analysisEveryone and their moms are on online networking nowadays, whether they're"preferring" organization pages on Facebook or tweeting protestations about items on Twitter. A Big Data arrangement fabricated to reap and analyze online networking movement, similar to IBM's Cognos Consumer Insights, a point arrangement running on IBM's BigInsights Big Data stage, can comprehend the jabber. Social mediacan give continuous experiences into how the business sector is reacting to items and battles. With those bits of knowledge, organizations can change their valuing, advancement, and battle arrangement on the fly for ideal results.Figure 2. Application area of Big DataCase of Big Data in Real world:•Consumer item organizations and retail associations are checking online networking like Facebook and Twitter to get an uncommon perspective into client conduct, inclinations, and item observation.•Manufacturers are observing moment vibration information from their hardware, which changes somewhat as it wears out, to foresee the ideal time to supplant or keep up.•Manufacturers are likewise observing informal organizations, however with an alternate objective than advertisers: They are utilizing it to identify reseller's exchangebolster issues before a guarantee disappointment turns out to be openly adverse.•The government is making information open at both the national, state, and city level for clients to grow new applications that can produce open great.•Financial Services associations are utilizing information mined from client connections to cut up their clients into finely tuned fragments.•Advertising and showcasing offices are following online networking to comprehend responsiveness to campaigns, advancements, and other promoting mediums.•Insurance organizations are utilizing Big Data investigation to see which home protection applications can be instantly prepared, and which ones need an approving in-individual visit from an operators.•By grasping social media, retail associations are drawing in brand promoters, changing the impression of brand rivals, and not with standing empowering eager clients to offer their items.•Hospitals are investigating medicinal information and patient records to predict those patients that are prone to look for readmission inside of a couple of months of release. The doctor's facility can then mediate with expectations of anticipating another expensive doctor's facility sit tight.•Web-based organizations are creating data items that consolidate information assembled from clients to offer additionally engaging proposals and more fruitful coupon programs.•Sports groups are utilizing information for following ticket deals and even for tracking team strategies.Figure 3. Architecture of Big DataThis figure 3 first extracts the social, archive, service data some part of operational data then transforms with new techniques then load in to server and finally Big Data analytic with latest technique.Figure 4. stages of Big DataThis figure 4 divides the data in to three stages.1.Data Acquisition form:this stage of data cover with streams, internet data, cloud data source, mobile data source, desktop data source and server data source.2.Data refining and processing form:this stage covers refining and processing the data of corporate Hub. Corporate data hub is combination of refining workloads and local workloads.3.Data Shipping form:this stage of architecture extract the data from different sources.IV.HADOOP ARCHITECTURESpring for Apache Hadoop streamlines providing so as to create Apache Hadoopa brought together design model and simple to utilize APIs for utilizing HDFS, MapReduce, Pig, and Hive. It likewise furnishes coordination with other Spring eco –system venture, for example, Spring Incorporation and Spring Cluster empowering you to create answers for enormous information ingest/fare and Hadoop work process organization.Apache Hadoop is a software patternfor preparing a lot of information over conceivably greatly parallel groups of servers. The key segment of Hadoop is the Hadoop Distributed File System,which deals with the data shared over the different servers. It is a direct result of HDFS that such a variety of servers can be overseen in parallel. HDFS is file based and does not require any data model to save and process data. It can store data of any structure, however is not a RDBMS. HDFS can deal with the capacity and access of an Web logs, XML documents type of data and the length of the data can be placed in a file and replicated into HDFS. The Hadoop base regularly runs MapReduce programs in parallel. MapReduce takes substantial datasets, extricates and changes valuable data, conveys the data to the different servers where handling happens, and amasses the outcomes into a smaller,easier-to-examine file. It doesn't perform analytics fundamentally; rather, it gives the system that controls the projects that perform the analytics. As of now, jobs can be run just a in batch, which restrains the utilization of Hadoop/MapReduce for real-time applications. In spite of the fact that Hadoop and MapReduce are talked about and regularly utilized together, they can be utilized independently. That is, Hadoop can be utilized without MapReduce and the other way around.Figure 5 outlines how process is carried out by using Hadoop/MapReduce. This is a basic process that should likewise be possible with SQL based query and a RDBMS, yet gives a decent sample of Hadoop/MapReduce handling. At the left is an information document with records containing Deer, Bear , River, and Car. The goal is to tally the quantity of times every word happens. The initial step is to part the records and then prepared by the clusters of servers, for example, Java and R language on the servers. The target in this case is to assemble the data by a split depending on the words. The MapReduce pattern then consolidations the mix/sort results for information to the reducer program, which thencalculates the number of times every word happens. This yield can then be input to an data warehouse where it might be consolidated with other information for analysis or accessed straight for wardly by different BI instruments .Figure 5. Hadoop ArchitectureV.RESULT AND DISCUSSIONBig data processing with spring framework results in distributed data store: spring framework enables resource and data aggregation on java. Java helps in improvement in execution efficiency by distributing application execution at different levels. Due to reducing costs of devices and networks data from real world is getting collected in data centres. A system that implements big data processing on spring framework is a combination of components like servers for judgment, accumulation and analysis to solve real life problems like traffic management and human resource management. Distributed parallel processing is required to perform statistical analysis of different vehicles at different or same place in one city or a comparison of different cities. In comparing with other distributed batch methods the performance increaseei ght times. Let us use this prototype to match any individual’s location and preference with product inventory of stores and malls and to generate the bills and deliver the product at the doorstep of customer in shortest possible time. The process shown in the figure can be explained in steps:Step 1: Individual’s location and preference is retrieved (Query 1)Step 2: Stores and malls details within a certain distance is retrieved (Query 2) Step 3: Individual’s information and store’s product information is matched (Query 3)Step 4: A bill is generated if they match.The processing load in step 2 and 3 is directly proportional to number of people. Dynamic load balancing by increasing dedicated servers reduces CPU usage and ensures high speed processing. Hence ensuring optimization of improvement in performance, resource efficiency and delivery synchronization.Figure 6. Architecture of big data with Spring FrameworkIn this figure 6 query 1, query 2, query 3 is based on spring framework of java that means all the query based code is stored in the given XML File, individual information is stored in oracle database. Finally coupon issued in the base of big data based query of spring framework of java and J2ee under the supervision Hadoop Architecture of Big Data follow in figure 7 shown below.Figure 7. Spring Framework with big dataVI. CONCLUSION AND FUTURE SCOPEIn this research article, we described the ongoing research to design and implement a big data with spring Framework.This model administers big data to ceaselessly trade asset cuts among machines, granting assets to those occupants requiring or qualified for additional, while having the capacity to figure out where the asset diminishment will be all the more financially compelling, i.e., will contribute in lesser degree to execution debasement.In future we have to implement big data with struts, spring and hibernate integration to reduce cost on infrastructure in java & J2ee base applications.中文译文基于Java/J2EE的Spring框架实现和分析大数据技术摘要—在JAVA Spring框架下的大数据技术时代,作为大数据中重要通道的Web服务器或应用服务器应该进行更新，以满足执行和强制要求。

JSP应用框架论文中英文资料对照外文翻译文献综述

JSP应用框架中英文资料对照外文翻译文献综述JSP APPLICATION FRAMEWORKS1.1 WHAT ARE APPLICATION FRAMEWORKS:A framework is a reusable, semi-complete application that can be specialized to produce custom applications [Johnson]. Like people, software applications are more alike than they are different. They run on the same computers, expect input from the same devices, output to the same displays, and save data to the same hard disks. Developers working on conventional desktop applications are accustomed to toolkits and development environments that leverage the sameness between applications. Application frameworks build on this common ground to provide developers with a reusable structure that can serve as the foundation for their own products.A framework provides developers with a set of backbone components that have the following characteristics:Frameworks are the classic build-versus-buy proposition. If you build it, you will understand it when you are done—but how long will it be before you can roll your own? If you buy it, you will have to climb the learning curve—and how long is that going to take? There is no right answer here, but most observers would agree that frameworks such as Struts provide a significant return on investment compared to starting from scratch, especially for larger projects.1.2 OTHER TYPES OF FRAMEWORKS:The idea of a framework applies not only to applications but to application components as well. Throughout this article, we introduce other types of frameworks that you can use with Struts. These include the Lucene search engine, the Scaffold toolkit, the Struts validator, and the Tiles tag library. Like application frameworks, these tools provide semi-complete versions of a subsystem that can be specialized to provide a custom component.Some frameworks have been linked to a proprietary development environment. This is not the case with Struts or any of the other frameworks shown in this book. You can use anydevelopment environment with Struts: Visual Age for Java, JBuilder, Eclipse, Emacs, and Textpad are all popular choices among Struts developers. If you can use it with Java, you can use it with Struts.1.3 ENABLING TECHNOLPGIES:Applications developed with Struts are based on a number of enabling technologies. These components are not specific to Struts and underlie every Java web application. A reason that developers use frameworks like Struts is to hide the nasty details behind acronyms like HTTP, CGI, and JSP. As a Struts developer, you don’t need to be an alphabet soup guru, but a working knowledge of these base technologies can help you devise creative solutions to tricky problems.1.4 HYPERTEXT TRANSFER PROTOCOL (HTTP):When mediating talks between nations, diplomats often follow a formal protocol.Diplomatic protocols are designed to avoid misunderstandings and to keep negotiations from breaking down. In a similar vein, when computers need to talk, they also follow a formal protocol. The protocol defines how data is transmitted and how to decode it once it arrives. Web applications use the Hypertext Transfer Protocol (HTTP) to move data between the browser running on your computer and the application running on the server.Many server applications communicate using protocols other than HTTP. Some of these maintain an ongoing connection between the computers. The application server knows exactly who is connected at all times and can tell when a connection is dropped. Because they know the state of each connection and the identity of each person using it, these are known as stateful protocols.By contrast, HTTP is known as a stateless protocol. An HTTP server will accept any request from any client and will always provide some type of response, even if the response is just to say no. Without the overhead of negotiating and retaining a connection, stateless protocols can handle a large volume of requests. This is one reason why the Internet has been able to scale to millions of computers.Another reason HTTP has become the universal standard is its simplicity. An HTTP request looks like an ordinary text document. This has made it easy for applications to make HTTP requests. You can even send an HTTP request by hand using a standard utility such as Telnet. When the HTTP response comes back, it is also in plain text that developers can read.The first line in the HTTP request contains the method, followed by the location of the requested resource and the version of HTTP. Zero or more HTTP request headers follow the initial line. The HTTP headers provide additional information to the server. This can include the browser type and version, acceptable document types, and the browser’s cookies, just toname a few. Of the seven request methods, GET and POST are by far the most popular.Once the server has received and serviced the request, it will issue an HTTP response. The first line in the response is called the status line and carries the HTTP protocol version, a numeric status, and a brief description of the status. Following the status line, the server will return a set of HTTP response headers that work in a way similar to the request headers.As we mentioned, HTTP does not preserve state information between requests. The server logs the request, sends the response, and goes blissfully on to the next request. While simple and efficient, a stateless protocol is problematic for dynamic applications that need to keep track of their users.Cookies and URL rewriting are two common ways to keep track of users between requests. A cookie is a special packet of information on the user’s computer. URL rewriting stores a special reference in the page address that a Java server can use to track users. Both approaches are seamless, and using either means extra work when developing a web application. On its own, a standard HTTP web server does not traffic in dynamic content. It mainly uses the request to locate a file and then returns that file in the response. The file is typically formatted using Hypertext Markup Language (HTML) [W3C, HTML] that the web browser can format and display. The HTML page often includes hypertext links to other web pages and may display any number of other goodies, such as images and videos. The user clicks a link to make another request, and the process begins a new.Standard web servers handle static content and images quite well but need a helping hand to provide users with a customized, dynamic response.DEFINITION: Static content on the Web comes directly from text or data files, like HTML or JPEG files. These files might be changed from time to time, but they are not altered automatically when requested by a web browser. Dynamic content, on the other hand, is generated on the fly, typically in response to an individualized request from a browser.1.5 COMMON GATEWAY INTERFACE (CGI):The first widely used standard for producing dynamic content was the Common Gateway Interface (CGI). CGI uses standard operating system features, such as environment variables and standard input and output, to create a bridge, or gateway, between the web server and other applications on the host machine. The other applications can look at the request sent to them by the web server and create a customized response.When a web server receives a request that’s intended for a CGI program, it runs that program and provides the program with information from the incoming request. The CGI program runs and sends its output back to the server. The web server then relays the response to the browser.CGI defines a set of conventions regarding what information it will pass as environment variables and how it expects standard input and output to be used. Like HTTP, CGI is flexible and easy to implement, and a great number of CGI-aware programs have been written.The main drawback to CGI is that it must run a new copy of the CGI-aware program for each request. This is a relatively expensive process that can bog down high-volume sites where thousands of requests are serviced per minute. Another drawback is that CGI programs tend to be platform dependent. A CGI program written for one operating system may not run on another.1.6 JA V A SERVLETS:Sun’s Java Servlet platform directly addresses the two main drawbacks of CGI programs. First, servlets offer better performance and utilization of resources than conventional CGI programs. Second, the write-once, run-anywhere nature of Java means that servlets are portable between operating systems that have a Java Virtual Machine (JVM).A Servlet looks and feels like a miniature web server. It receives a request and renders a response. But, unlike conventional web servers, the Servlet application programming interface (API) is specifically designed to help Java developers create dynamic applications.The Servlet itself is simply a Java class that has been compiled into byte code, like any other Java object. The Servlet has access to a rich API of HTTP-specific services, but it is still just another Java object running in an application and can leverage all your other Java assets.To give conventional web servers access to servlets, the servlets are plugged into containers. The Servlet container is attached to the web server. Each Servlet can declare what URL patterns it would like to handle. When a request matching a registered pattern arrives, the web server passes the request to the container, and the container invokes the Servlet.But unlike CGI programs, a new Servlet is not created for each request. Once the container instantiates the Servlet, it will just create a new thread for each request. Java threads are much less expensive than the server processes used by CGI programs. Once the Servlet has been created, using it for additional requests incurs very little overhead. Servlet developers can use the init () method to hold references to expensive resources, such as database connections or EJB Home Interfaces, so that they can be shared between requests. Acquiring resources like these can take several seconds—which is longer than many surfers are willing to wait.The other edge of the sword is that, since servlets are multithreaded, Servlet developers must take special care to be sure their servlets are thread-safe.1.7 JA V ASERVER PAGES:While Java servlets are a big step up from CGI programs, they are not a panacea. Togenerate the response, developers are still stuck with using println statements to render the HTML. Code that looks like:out.println("<P>One line of HTML.</P>");out.println("<P>Another line of HTML.</P>");It is all too common in servlets that generate the HTTP response. There are libraries that can help you generate HTML, but as applications grow more complex, Java developers end up being cast into the role of HTML page designers. Meanwhile, given the choice, most project managers prefer to divide development teams into specialized groups. They like HTML designers to be working on the presentation while Java engineers sweat the business logic. Using servlets alone encourages mixing markup with business logic, making it difficult for team members to specialize.To solve this problem, Sun turned to the idea of using server pages to combine scripting and templating technologies into a single component. To build Java Server Pages, developers start by creating HTML pages in the same old way, using the same old HTML syntax. To bring dynamic content into the page, the developer can also place JSP scripting elements on the page. Scripting elements are tags that encapsulate logic that is recognized by the JSP. You can easily pick out scripting elements on JSP pages by looking for code that begins with <% and ends with %>.To be seen as a JSP page, the file just needs to be saved with an extension of jsp.When a client requests the JSP page, the container translates the page into a source code file for a Java Servlet and compiles the source into a Java class file—just as you would do if you were writing a Servlet from scratch. At runtime, the container can also check the last modified date of the JSP file against the class file. If the JSP file has changed since it was last compiled, the container will retranslate and rebuild the page all over again.Project managers can now assign the presentation layer to HTML developers, who then pass on their work to Java developers to complete the business-logic portion. The important thing to remember is that a JSP page is really just a Servlet. Anything you can do with a Servlet, you can do with a JSP.1.8 JA V ABEANS:JavaBeans are Java classes which conform to a set of design patterns that make them easier to use with development tools and other components.DEFINITION: A JavaBean is a reusable software component written in Java. To qualify as a JavaBean, the class must be concrete and public, and have a non-argument constructor. JavaBeans expose internal fields as properties by providing public methods that follow a consistent design pattern. Knowing that the property names follow this pattern, other Javaclasses are able to use introspection to discover and manipulate JavaBean properties.The JavaBean design patterns provide access to the bean’s internal state through two flavors of methods: accessors are used to read a JavaBean’s state; mutators are us ed to change a JavaBean’s state.Mutators are always prefixed with lowercase token set followed by the property name. The first character in the property name must be uppercase. The return value is always void—mutators only change property values, they do not retrieve them. The mutator for a simple property takes only one parameter in its signature, which can be of any type. Mutators are often nicknamed setters after their prefix.The mutator method signature for a weight property of the type Double would be:public void setWeight(Double weight);A similar design pattern is used to create the accessor method signature. Accessor methods are always prefixed with the lowercase token get, followed by the property name. The first character in the property name must be uppercase. The return value will match the method parameter in the corresponding mutator. Accessors for simple properties cannot accept parameters in their method signature. Not surprisingly, accessors are often called getters.The accessor method signature for our weight property is：public Double getWeight();If the accessor returns a logical value, there is a variant pattern. Instead of using the lowercase token get, a logical property can use the prefix is, followed by the property name. The first character in the property name must be uppercase. The return value will always be a logical value—either boolean or Boolean. Logical accessors cannot accept parameters in their method signature.The boolean accessor method signature for an on property would be:public boolean isOn();The canonical method signatures play an important role when working with Java- Beans. Other components are able to use the Java Reflection API to discover a JavaBean’s properties by looking for methods prefixed by set, is, or get. If a component finds such a signature on a JavaBean, it knows that the method can be used to access or change the bean’s properties.Sun introduced JavaBeans to work with GUI components, but they are now used with every aspect of Java development, including web applications. When Sun engineers developed the JSP tag extension classes, they designed them to work with JavaBeans. The dynamic data for a page can be passed as a JavaBean, and the JSP tag can then use the bean’s properties to customize the output.JSP应用框架1.1 什么是应用框架：框架（framework）是可以被重用的一种半成品的应用程序，我们可以用它来制作专门的定制程序。

Servlet和JSP技术简介中英文对照外文翻译文献

中英文资料外文翻译An Overview of Servlet and JSP Technology 1.1A Servlet's JobServlets are Java programs that run on Web or application servers, acting as a middle layer between requests coming from Web browsers or other HTTP clients and databases or applications on the HTTP server. Their job is to perform the following tasks, as illustrated in Figure 1-1.Figure 1-11．Read the explicit data sent by the client.The end user normally enters this data in an HTML form on a Web page. However, the data could also come from an applet or a custom HTTP client program.2．Read the implicit HTTP request data sent by the browser.Figure 1-1 shows a single arrow going from the client to the Web server (the layer where servlets and JSP execute), but there are really two varieties of data: the explicit data that the end user enters in a form and the behind-the-scenes HTTP information. Both varieties are critical. The HTTP information includes cookies, information about media types and compression schemes the browser understands, and so on.3．Generate the results.This process may require talking to a database, executing an RMI or EJB call, invoking a Web service, or computing the response directly. Your real data may be in a relational database. Fine. But your database probably doesn't speak HTTP or return results in HTML, so the Web browser can't talk directly to the database. Even if it could, for security reasons, you probably would not want it to. The same argument applies to most other applications. You need the Web middle layer to extract the results inside a document.4．Send the explicit data (i.e., the document) to the client.This document can be sent in a variety of formats, including text (HTML or XML), binary (GIF images), or even a compressed format like gzip that is layered on top of some other underlying format. But, HTML is by far the most common format, so an important servlet/JSP task is to wrap the results inside of HTML.5．Send the implicit HTTP response data.Figure 1-1 shows a single arrow going from the Web middle layer (the servlet or JSP page) to the client. But, there are really two varieties of data sent: the document itself and the behind-the-scenes HTTP information. Again, both varieties are critical to effective development. Sending HTTP response data involves telling the browser or other client what type of document is being returned (e.g., HTML), setting cookies and caching parameters, and other such tasks.1.2Why Build Web Pages Dynamically?Many client requests can be satisfied by prebuilt documents, and the server would handle these requests without invoking servlets. In many cases, however, a static result is not sufficient, and a page needs to be generated for each request. There are a number of reasons why Web pages need to be built on-the-fly:1．The Web page is based on data sent by the client.For instance, the results page from search engines and order-confirmation pages at online stores are specific to particular user requests. You don't know what to display until you read the data that the user submits. Just remember that the user submits twokinds of data: explicit (i.e., HTML form data) and implicit (i.e., HTTP request headers). Either kind of input can be used to build the output page. In particular, it is quite common to build a user-specific page based on a cookie value.2．The Web page is derived from data that changes frequently.If the page changes for every request, then you certainly need to build the response at request time. If it changes only periodically, however, you could do it two ways: you could periodically build a new Web page on the server (independently of client requests), or you could wait and only build the page when the user requests it. The right approach depends on the situation, but sometimes it is more convenient to do the latter: wait for the user request. For example, a weather report or news headlines site might build the pages dynamically, perhaps returning a previously built page if that page is still up to date.3．The Web page uses information from corporate databases or other server-side sources.If the information is in a database, you need server-side processing even if the client is using dynamic Web content such as an applet. Imagine using an applet by itself for a search engine site:"Downloading 50 terabyte applet, please wait!" Obviously, that is silly; you need to talk to the database. Going from the client to the Web tier to the database (a three-tier approach) instead of from an applet directly to a database (a two-tier approach) provides increased flexibility and security with little or no performance penalty. After all, the database call is usually the rate-limiting step, so going through the Web server does not slow things down. In fact, a three-tier approach is often faster because the middle tier can perform caching and connection pooling.In principle, servlets are not restricted to Web or application servers that handle HTTP requests but can be used for other types of servers as well. For example, servlets could be embedded in FTP or mail servers to extend their functionality. And, a servlet API for SIP (Session Initiation Protocol) servers was recently standardized(see /en/jsr/detail?id=116). In practice, however, this use of servlets has not caught on, and we'll only be discussing HTTP servlets.1.3The Advantages of Servlets Over "Traditional" CGIJava servlets are more efficient, easier to use, more powerful, more portable, safer, and cheaper than traditional CGI and many alternative CGI-like technologies.1．EfficientWith traditional CGI, a new process is started for each HTTP request. If the CGI program itself is relatively short, the overhead of starting the process can dominate the execution time. With servlets, the Java virtual machine stays running and handles each request with a lightweight Java thread, not a heavyweight operating system process. Similarly, in traditional CGI, if there are N requests to the same CGI program, the code for the CGI program is loaded into memory N times. With servlets, however, there would be N threads, but only a single copy of the servlet class would be loaded. This approach reduces server memory requirements and saves time by instantiating fewer objects. Finally, when a CGI program finishes handling a request, the program terminates. This approach makes it difficult to cache computations, keep database connections open, and perform other optimizations that rely on persistent data. Servlets, however, remain in memory even after they complete a response, so it is straightforward to store arbitrarily complex data between client requests.2．ConvenientServlets have an extensive infrastructure for automatically parsing and decoding HTML form data, reading and setting HTTP headers, handling cookies, tracking sessions, and many other such high-level utilities. In CGI, you have to do much of this yourself. Besides, if you already know the Java programming language, why learn Perl too? You're already convinced that Java technology makes for more reliable and reusable code than does Visual Basic, VBScript, or C++. Why go back to those languages for server-side programming?3．PowerfulServlets support several capabilities that are difficult or impossible to accomplish with regular CGI. Servlets can talk directly to the Web server, whereas regular CGI programs cannot, at least not without using a server-specific API. Communicating with the Web server makes it easier to translate relative URLs into concrete path names, for instance. Multiple servlets can also share data, making it easy to implement database connection pooling and similar resource-sharing optimizations. Servlets can also maintain information from request to request, simplifying techniques like session tracking and caching of previous computations.4．PortableServlets are written in the Java programming language and follow a standard API. Servlets are supported directly or by a plugin on virtually every major Web server. Consequently, servlets written for, say, Macromedia JRun can run virtually unchanged on Apache Tomcat, Microsoft Internet Information Server (with a separate plugin), IBM WebSphere, iPlanet Enterprise Server, Oracle9i AS, or StarNine WebStar. They are part of the Java 2 Platform, Enterprise Edition (J2EE; see /j2ee/), so industry support for servlets is becoming even more pervasive.5．InexpensiveA number of free or very inexpensive Web servers are good for development use or deployment of low- or medium-volume Web sites. Thus, with servlets and JSP you can start with a free or inexpensive server and migrate to more expensive servers with high-performance capabilities or advanced administration utilities only after your project meets initial success. This is in contrast to many of the other CGI alternatives, which require a significant initial investment for the purchase of a proprietary package.Price and portability are somewhat connected. For example, Marty tries to keep track of the countries of readers that send him questions by email. India was near the top of the list, probably #2 behind the U.S. Marty also taught one of his JSP andservlet training courses (see /) in Manila, and there was great interest in servlet and JSP technology there.Now, why are India and the Philippines both so interested? We surmise that the answer is twofold. First, both countries have large pools of well-educated software developers. Second, both countries have (or had, at that time) highly unfavorable currency exchange rates against the U.S. dollar. So, buying a special-purpose Web server from a U.S. company consumed a large part of early project funds.But, with servlets and JSP, they could start with a free server: Apache Tomcat (either standalone, embedded in the regular Apache Web server, or embedded in Microsoft IIS). Once the project starts to become successful, they could move to a server like Caucho Resin that had higher performance and easier administration but that is not free. But none of their servlets or JSP pages have to be rewritten. If their project becomes even larger, they might want to move to a distributed (clustered) environment. No problem: they could move to Macromedia JRun Professional, which supports distributed applications (Web farms). Again, none of their servlets or JSP pages have to be rewritten. If the project becomes quite large and complex, they might want to use Enterprise JavaBeans (EJB) to encapsulate their business logic. So, they might switch to BEA WebLogic or Oracle9i AS. Again, none of their servlets or JSP pages have to be rewritten. Finally, if their project becomes even bigger, they might move it off of their Linux box and onto an IBM mainframe running IBM WebSphere. But once again, none of their servlets or JSP pages have to be rewritten.6．SecureOne of the main sources of vulnerabilities in traditional CGI stems from the fact that the programs are often executed by general-purpose operating system shells. So, the CGI programmer must be careful to filter out characters such as backquotes and semicolons that are treated specially by the shell. Implementing this precaution is harder than one might think, and weaknesses stemming from this problem are constantly being uncovered in widely used CGI libraries.A second source of problems is the fact that some CGI programs are processed by languages that do not automatically check array or string bounds. For example, in C and C++ it is perfectly legal to allocate a 100-element array and then write into the 999th "element," which is really some random part of program memory. So, programmers who forget to perform this check open up their system to deliberate or accidental buffer overflow attacks.Servlets suffer from neither of these problems. Even if a servlet executes a system call (e.g., with Runtime.exec or JNI) to invoke a program on the local operating system, it does not use a shell to do so. And, of course, array bounds checking and other memory protection features are a central part of the Java programming language.7．MainstreamThere are a lot of good technologies out there. But if vendors don't support them and developers don't know how to use them, what good are they? Servlet and JSP technology is supported by servers from Apache, Oracle, IBM, Sybase, BEA, Macromedia, Caucho, Sun/iPlanet, New Atlanta, ATG, Fujitsu, Lutris, Silverstream, the World Wide Web Consortium (W3C), and many others. Several low-cost plugins add support to Microsoft IIS and Zeus as well. They run on Windows, Unix/Linux, MacOS, VMS, and IBM mainframe operating systems. They are the single most popular application of the Java programming language. They are arguably the most popular choice for developing medium to large Web applications. They are used by the airline industry (most United Airlines and Delta Airlines Web sites), e-commerce (), online banking (First USA Bank, Banco Popular de Puerto Rico), Web search engines/portals (), large financial sites (American Century Investments), and hundreds of other sites that you visit every day.Of course, popularity alone is no proof of good technology. Numerous counter-examples abound. But our point is that you are not experimenting with a new and unproven technology when you work with server-side Java.Servlet和JSP技术简介1.1Servlet的功能Servlets是运行在Web或应用服务器上的Java程序，它是一个中间层，负责连接来自Web浏览器或其他HTTP客户端和HTTP服务器上的数据库或应用程序。

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中英文资料外文翻译文献基于J2EE在分布式环境下的底层结构的自动动态配置的应用摘要：为了实现广域网中符合工业标准基于组件的应用程序中动态的可适应性，我们需要一种框架来在这样的环境里自动化地配置J2EE 应用程序。

这种需要对于哪怕在单一的应用程序服务器上尝试部署J2EE应用的人来说也显而易见，这种任务设计到大量的系统服务和应用组件的配置。

关键词：j2ee；动态配置；分布式；组件；1 前言近几年，我们已经看到基于组件的企业应用开发的显著增加。

这种应用程序通常被部署在公司的内部网或者是因特网上，以高事务容量，大量的用户和覆盖范围广的访问为特征，它通常会被部署在中央区域，采用服务器集群来均衡负载从而支持用户下载。

但是这种平均负荷的方法被证明只对减少应用转发的用户可以察觉的反应时间有效，而对于减少网络方面的延迟作用不大，垂直分割（例如…运行网络层和事务层在不同的虚拟机）被用于错误分离和均衡负荷，但是它是不符合实际的由于远程调运的大量使用显著地增加了运行时时间。

最近的著作已经表明在广域网中利用垂直负荷而不引起前面所述的超时问题的可行性。

那非研究的主要结论可以概括如下：(1) 应用合适的应用程序，在广域网中的垂直负荷可以察觉的延迟。

(2) 广域垂直层需要复制应用层组件而且需要维持和原组件间的一致性。

(3) 新加的复制组件可以被动态配置以满足新的需要。

(4) 事实上，不同的复制组件可能会根据应用不同的方式实现相组件。

(5) 新的请求路径可以复用先前的组件配置路径。

应用智能监视和人工智能规划方法再结合那个研究得出的结论，我们看到通过动态布置基于动态监视的额外的应用组件，在广域网中符合工业标准基于组件的应用程序中动态的可适应性是可以实现的。

然而，为了实现这种动态可适性，我们需要一种框架来在这样的环境里自动化地配置J2EE 应用程序。

这种需要对于哪怕在单一的应用程序服务器上尝试布置J2EE应用的人来说也显而易见，这种任务设计到大量的系统服务和应用组件的配置。

例如你必须在配置和部署应用组件前先建立JDBC数据源，设立消息目的地和资源适配器。

在需要跨越多个节点服务器的广域网配置中，这将更加复杂，因为更多的便利内部节点通信的系统服务需要配置和启动，而且多种配置数据比如IP地址，端口号，JNDI名字和其他的数据在多个节点的配置文件中必须维持一致性。

这种分布式配置框架必须满足：(1) 声明内部组件一致性规范和定义它对组件配置部署的影响。

(2) 声明应用程序组件对应用服务器，以及它们的配置和部署的依赖性。

(3) 提供简单但可表达的抽象方法去控制通过部署和拆卸组件获得的适用性。

(4) 能够复用服务和组件从而高效的利用网路节点资源。

(5) 提供上述便利而不会增加应用程序员的设计负担。

在本论文中，我们提出自动动态部署J2EE应用程序的框架涉及了上面的所有问题，这种框架为组件定义了结构描述语言，链接说明和集合。

这种组件说明语言用来描述应用程序组件和链接，它使得应用组件与系统组件中清晰的分开。

一种灵活的系统类型用来定义组件接口和端口的兼容性。

一种为配置组件属性而开发的定义和表述语言允许内部组件间独立的规范和组件间属性的继承。

组件集合语言允许先前定义的复制的组件通过连接合适的端口集合到应用路径，连接时通过链接复制对象和具体把这些复制组件映射到目标应用服务器节点。

组件配置过程评估了应用程序路径的正确性，确认在系统组件上的应用组件的独立性和完成复制组件的部署。

根据这些配置使先前部署的复制组件在新的路径中得以匹配和复用的努力正在做出。

我们把这种架构作为JBoss开源java应用服务器的一部分加以实现，在几个J2EE样本程序比如Java PetStore,，RUB和TPC_W_NYU中进行测试。

这种架构实现利用了JBoss的可扩展的微内核结构，基于JMX 规范。

JBoss的组件结构允许根据部署应用程序的需要增加服务配置。

我们相信通过动态部署和拆卸系统服务来重构应用服务器对构建高效资源框架的动态分布部署的J2EE 应用程序来说是非常必要的。

本文如下部分是这样组织的。

第2部分提供了必要的背景以理解和研究有关的J2EE组件技术规范。

第3部分对这种架构给出了一般性的描述。

第4部分更深入的描述了有关这种架构特别重要的和有趣的内部机制。

第五部分描述了如何实现这种架构，相关联的工作将在第六部分介绍。

2 J2EE背景知识2.1 介绍组件框架。

组件框架是一种中间件系统，它支持遵守一定标准的有不同组件构成的应用程序。

应用组件被塞入这种确立它们运行环境和规定它们交互的框架中。

这通常是通过容器，组件持有者来实现的。

这种容器也提供通常需要的功能以实现命名，安全性，事务，和持久性！组件框架为组件的执行提供了一个集成的环境，因此显著的减少了在设计，实现，部署和维护应用程序时工作。

现在工业上的组件框架标准以对象管理组的CORBA组件模型，SUN 公司的JA V A 2 Platform J企业版[J2EE]和微软公司的.NET标准，其中在企业里应用最为广泛的组件框架是2EEE。

J2EE. J2EE是开发多层企业应用JA V A程序的综合性的标准。

J2EE规范定义如下：(1) 组件编程模型。

(2) 组件和主服务器的链接。

(3) 服务器提供给组件的服务。

(4) 各种各样的人物角色。

(5) 兼容性检验装置和编译测试程序。

在众多的服务列表中，消息通信，事务处理，命名机制和其它应用组件用到的服务是应用服务器必须提供的。

用J2EE进行应用开发必须遵守经典的3层结构—表现层，业务层和企业信息系统层。

属于各层的J2EE组件在开发时遵守具体的J2EE标准。

1、表现层或者网络层这一层实际上又被分为客户端和服务器端。

客户端包括浏览器，applets，Java应用程序等和负责和服务器端的表现层或者业务层进行交互。

服务器端包括servle t、jsp和静态网页内容。

这些组件负责把业务数据传递给终端用户。

数据本身通常从业务层获得有时也从企业信息系统层直接获得。

表现层的服务器端通常通过Http协议来进行访问。

2、业务层或者EJB层这一层包含EJB，即企业应用的事务逻辑模型。

这些组件提供了持久化机制和事务支持。

EJB中的组件通过RMI被调用。

在Java虚拟机调用或者异步的消息传递，取决与EJB组件的类型。

EJB规范定义了很多种组件。

它们在调用风格（同步和异步，本地和远程）与状态（完全状态，不可持久状态，可持久）方面不同。

同步调用的EJB组件通过特定的工厂代理对象来表现自己。

这种工厂代理对象通常被EJB部署者绑定在JNDI 中。

EJB对象允许或者本地EJB对象是特定EJB实例的代理。

3、企业信息系统或者数据层这一层指的就是企业信息系统，比如关系数据库，ERP系统，消息系统等。

业务层和持久层在资源适配器的帮助下与该层进行通信。

资源适配器在Java连结结构中被定义。

J2EE编程模型一直被认为是分布式的编程模型，在该模型中应用组件在J2EE服务器上运行并且彼此可以相互交互。

经过初始化说明和第一个服务实现后，该技术，更显著的说EJB技术，已经明显地从纯粹的分布式计算模型转向了本地交互。

转变的背后有合理的性能有关的原因，然而分布式的特征现在还存在。

J2EE规范已经经过了好几次修订，现在最稳定的版本是1.3，1.4版本正处于重审阶段。

我们应该把注意力放在1.3版本上，而实际上是在学习后者。

适用与商业的J2EE实现可以大量的从BEA系统，IBM，Oracle等赞助商得到。

包括JBoss和JOnAS在内的开源实现据称兼容性也不错。

最近名单上有多出了新的Apache project Geronimo。

2.2 J2EE组件编程模型在我们基本的J2EE组件前，先让我们强调一下什么是组件。

软件组件是有一系列的具体的接口和明确的上下文环境构成。

它可以被独立的部署而且易于被第三方重构。

根据以上的定义，如下的组成J2EE应用程序的实体可以看作是软件组件：(1) EJBS（会话，实体，消息驱动）。

(2) Web组件（Servle t、JSP）。

.(3) 消息目的。

(4) 数据源。

EJB和Web组件被部署在由应用服务赞助商提供的容器中.它们有定义良好的容器规则来管理生命周期，线程，持久化和其他问题。

EJB和Web组件都利用JNDI目录机制去寻找资源和它们想要交互的其EJB组件。

目录被执行的JNDI环境被独立的由容器的每个组件加以维护。

该种环境下的绑定机制通常由组件部署的解释者加以配置。

消息目的地，像对话和队列，是由消息服务执行所提供的资源。

数据源是提供给应用服务器的为事务组件进入到企业信息服务层提供数据接口，通常由被应用服务器管理的JDBC连接池实例化。

一个J2EE编程者明确编写的项目只有EJB和Web组件。

这些用户编写的组件彼此交互而且系统服务可以是明显的也可以是隐含的。

例如，EJB开发者可以选择明确的事务区分方式，这种方式意味着开发者假设通过定义良好接口的事务经理服务平台来书写明确的程序交互。

或者，开发者也可选择容器管理事务区分的方式。

这样由于组件的事务行为通过他的描述者来定义而且全部用EJB容器来处理，因此作为一个隐式独立的EJB提供潜在的事务管理服务。

2.3 组件间的链接2.3.1 远程交互J2EE仅定义了三种可以在不同应用服务器间传递的基本组件间连接类型。

在这三种情况下，通信通过特定的Java对象来完成。

(1) 远程EJB调用：同步的EJB调用通过主EJB对象和EJB对象接口来实现。

(2) Java连结器的外部连接：同步消息接收，同步和异步消息发送，用连接工厂和连接接口进行数据库查询。

(3) Java连接器的内部连接：异步消息传递进入消息驱动Bean只能使用Activation Spec 对象。

在前两个实例中，应用组件的开发者不仅书写执行在组件的运行时JNDI环境中的对象目录代码，而且书写发布方法调用，与远程的组件相互发送和接受消息。

组件的运行时JNDI环境为每一个组件部署所创建。

环境中的绑定在组件部署时由部署者进行初始化。

这些绑定被假设为是静态的，因为规格中没有提供任何的容器和组件间协议去提示绑定发生了变化。

在Java连接器的内部通信情景下，Activation Spec 对象查询以及所有的相应的M容器隐式的完成。

虽然查询的协议还没有被标准化，但是假设一个基于JMX 或者JNDI的查询是合理的。

假设潜在的应用服务器提供了所有的设备去控制部署过程的每一步，那么在两个J2EE组件间确立一个连接需要涉及：(1) 部署目标组件类。

(2) 创建一个特定的Java对象用作目标组件代理。

(3) 用组件的命名服务去绑定目标。

(4) 启动目标组件。

(5) 部署指定的组件类。

(6) 在主机的命名服务中，创建和进行指定组件的运行环境。