jsp技术简介
JSP完整PPT课件
• JSP的编译
– JSP的页面代码不能直接运行 – JSP的页面代码被编译成Java的源代码 – 编译生成的Java类实现javax.servlet.jsp.HttpJspPage接口
• HttpJspPage接口的继承关系如下图
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JSP与Servlet
• JSP与Servlet的对应
• Web容器调用实例的jspInit方法；准备阶段完成
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JSP的运行 Ⅵ
• Web容器调用_ jspService方法处理相应的请求
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JSP的运行 Ⅶ
• 当需要销毁实例时，Web容器调用jspDestroy方法
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JSP脚本元素Ⅰ
• 脚本元素包括：注释、声明和表达式。 • HTML注释（显式注释）：
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JSP内置对象Ⅱ
• 和Servlet相关的内置对象
– page对象
• page对象代表JSP本身，更准确的说，它代表JSP被转译后的 Servlet。因此，他可以调用Servlet类所定义的方法。实际开发中很 少使用
– config对象
• 该对象里存放Servlet的初始参数值（初始数据结构）。和page对象 一样都很少被用到
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JSP内置对象Ⅲ
• Input/Output有关的内置对象
– out对象
• out对象代表了向客户端发送数据的对象，与response对象不同，通过out对 象发送的内容将是浏览器需要显示的内容，是文本级的，可以通过out对象 直接向客户端写一个由程序动态生成的HTML文件
jsp网站开题报告
jsp网站开题报告JSP网站开题报告一、引言随着互联网的快速发展，网站已经成为人们获取信息、交流和商业活动的重要平台。
为了满足用户的需求，网站的设计与开发变得越来越重要。
本文将介绍我所选择的主题——JSP网站开发，并探讨其背景、意义和目标。
二、背景JSP（Java Server Pages）是一种用于开发动态网页的Java技术。
它允许开发人员在HTML页面中嵌入Java代码，通过服务器端的处理生成动态内容。
相比于其他技术，JSP具有更高的灵活性和扩展性，因此被广泛应用于各种网站的开发中。
三、意义1. 提供个性化服务：通过JSP网站的开发，我们可以根据用户的需求和偏好提供个性化的服务。
通过收集用户信息和行为分析，我们可以为用户推荐相关的内容和产品，提高用户的满意度和粘性。
2. 实现交互功能：JSP网站可以通过与数据库的交互实现用户注册、登录、评论、购物等功能。
通过服务器端的处理，可以确保数据的安全性和一致性，提供更好的用户体验。
3. 提升网站性能：JSP网站可以通过使用缓存、优化数据库查询等技术来提高网站的性能。
通过减少对服务器资源的占用和网络传输的数据量，可以提高网站的响应速度，减少用户等待时间。
四、目标1. 设计用户友好的界面：一个好的网站应该具有直观、简洁、美观的界面，能够吸引用户的注意力并提供良好的用户体验。
我们将通过合理的布局、清晰的导航和美观的设计来实现这一目标。
2. 实现个性化推荐功能：通过收集用户的浏览记录、搜索关键词等信息，我们将开发算法来为用户推荐相关的内容和产品。
通过个性化的推荐，我们可以提高用户的满意度和转化率。
3. 提供高效的数据库查询：通过优化数据库查询语句、建立索引等技术手段，我们将提高网站的性能和响应速度。
通过减少不必要的数据查询和网络传输，我们可以提高用户的体验和网站的可用性。
五、开发计划1. 需求分析：我们将与客户进行充分的沟通，了解他们的需求和期望。
通过需求分析，我们将明确网站的功能和设计要求。
Jsp技术在仓储管理中的应用
Jsp技术在仓储管理中的应用关键词：jsp技术自动化网络化一概述在自动化立体仓库系统中, 应用网络技术实现远程控制和信息管理,不仅可以实现资源共享,而且可以提高系统应用维护能力, 更方便系统发挥远程管理能力, 所以网络化管理是自动化立体仓库系统不可缺少的重要组成部分。
随着网络技术飞速发展和不断完善,基于网络技术的各种应用系统解决方案在相当多的领域得到广泛应用。
目前实现仓库的网络化管理与控制有多种方法, 但都存在各自的局限性, 最突出的问题是程序响应速度慢和计算机系统资源利用率小。
目前微软发布的. Net框架虽然具有支持多种高级语言、代码执行效率高、类库丰富、数据库存取模型先进等特点, 但. Net技术却并不支持所有的操作系统,存在一定的局限性。
JSP(Java Server Page)技术的出现与发展,为系统采用网络化的研究提供了新的手段和方法。
JSP技术具有.Net技术的优点并克服了以上问题,是一种用来开发Web应用程序的新技术,其具有如下特点:(1)在开发网络环境下分布式多层结构应用程序利用Java语言固有的特点使其具有相当的优势; (2)应用JSP技术使Java在服务器端的功能有了极大的提高; (3)应用JSP技术进行网络编程时具备一些高级特性,如访问权限、安全性和易于进行庞大数据库的动态访问等; (4)应用JSP技术能够实现远程信息资源共享。
本文介绍了采用JSP技术的自动化立体仓库管理与控制系统。
二JSP简介JSP(Java Server Pages)是由Sun Microsystems公司倡导、许多公司参与一起建立的一种动态网页技术标准。
JSP技术有点类似ASP技术，它是在传统的网页HTML文件中插入Java程序段和JSP标记，从而形成JSP文件。
用JSP开发的Web应用是跨平台的，既能在Linux下运行，也能在其他操作系统上运行。
JSP技术使用Java编程语言编写类XML的tags和scriptlets，来封装产生动态网页的处理逻辑。
JSP技术概述和应用框架外文翻译
外文原文Overview of JSP Technology and JSP application frameworksAutor: Zambon Giulio/ Sekler MichaelSource: Springer-Verlag New York Inc1．Benefits of JSPJSP 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.2.Advantages of JSP Over Competing TechnologiesA 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, ColdFusion 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..So, the question becomes: why use JSP instead of one of these other technologies? Our first response is that we are not arguing that everyone should. Several of those other technologies are quite good and are reasonable options in some situations. In other situations, however, JSP is clearly better. Here are a few of the reasons.2.1 Versus .NET and Active Server Pages (ASP). NET is well-designed technology from Microsoft. is the part that directly competes with servlets and JSP. The advantages of JSP are two fold.First, JSP is portable to multiple operating systems and Web servers; you aren't locked into deploying on Windows and IIS. Although the core .NET platform runs on a few non-Windows platforms, the ASP part does not. You cannot expect to deploy serious applications on multiple servers and operating systems. For some applications, this difference does not matter. For others, it matters greatly.Second, for some applications the choice of the underlying language matters greatly. For example, although .NET's C# language is very well designed and is similar to Java, fewer programmers are familiar with either the core C# syntax or the many auxiliary libraries. In addition, many developers still use the original version of ASP. With this version, JSP has a clear advantage for the dynamic code. With JSP, the dynamic part is written in Java, not VBScript or another ASP-specific language, so JSP is more powerful and better suited to complex applications that require reusable components.You could make the same argument when comparing JSP to the previous version of ColdFusion; with JSP you can use Java for the "real code" and are not tied to a particular server product. However, the current release of ColdFusion is within the context of a J2EE server, allowing developers to easily mix ColdFusion and servlet/JSP code.2.2 Versus PHPPHP (a recursive acronym for "PHP: Hypertext Preprocessor") is a free, open-source, HTML-embedded scripting language that is somewhat similar to both ASP and JSP. One advantage of JSP is that the dynamic part is written in Java, which already has an extensive API for networking, database access, distributed objects, and the like, whereas PHP requires learning an entirely new, less widely used language. A second advantage is that JSP is much more widely supported by tool and server vendors than is PHP.2.3 Versus Pure ServletsJSP doesn't provide any capabilities that couldn't, in principle, be accomplished with servlets. In fact, JSP documents are automatically translated into servlets behind the scenes. But it is more convenient to write (and to modify!) regular HTML than to use a zillion println statements to generate the HTML. Plus, by separating the presentation from the content, you can put different people on different tasks: your Web page design experts can build the HTML by using familiar tools and either leave places for your servlet programmers to insert the dynamic content or invoke the dynamic content indirectly by means of XML tags.Does this mean that you can just learn JSP and forget about servlets? Absolutely not! JSP developers need to know servlets for four reasons:1. JSP pages get translated into servlets. You can't understand how JSP works without understanding servlets.2. JSP consists of static HTML, special-purpose JSP tags, and Java code. What kind of Java code? Servlet code! You can't write that code if you don't understand servlet programming.3. Some tasks are better accomplished by servlets than by JSP. JSP is good at generating pages that consist of large sections of fairly well structured HTML or other character data. Servlets are better for generating binary data,building pages with highly variable structure, and performing tasks (such as redirection) that involve little or no output.4. Some tasks are better accomplished by a combination of servlets and JSP than by either servlets or JSP alone.2.4 Versus JavaScriptJavaScript, which is completely distinct from the Java programming language, is normally used to dynamically generate HTML on the client, building parts of the Web page as the browser loads the document. This is a useful capability and does not normally overlap with the capabilities of JSP (which runs only on the server). JSP pages still include SCRIPT tags for JavaScript, just as normal HTML pages do. In fact, JSP can even be used to dynamically generate the JavaScript that will be sent to the client. So, JavaScript is not a competing technology; it is a complementary one.It is also possible to use JavaScript on the server, most notably on Sun ONE (formerly iPlanet), IIS, and BroadVision servers. However, Java is more powerful, flexible, reliable, and portable.2.5 Versus WebMacro or VelocityJSP is by no means perfect. Many people have pointed out features that could be improved. This is a good thing, and one of the advantages of JSP is that the specification is controlled by a community that draws from many different companies. So, the technology can incorporate improvements in successive releases.However, some groups have developed alternative Java-based technologies to try to address these deficiencies. This, in our judgment, is a mistake. Using a third-party tool like Apache Struts that augments JSP and servlet technology is a good idea when that tool adds sufficient benefit to compensate for the additional complexity. But using a nonstandard tool that tries to replace JSP is a bad idea. When choosing a technology, you need to weigh many factors: standardization, portability, integration, industry support, and technical features. The arguments for JSP alternatives have focused almost exclusively on the technical features part. But portability, standardization, and integration are also very important. For example, the servlet and JSP specifications define a standard directory structure for Web applications and provide standard files (.war files) for deploying Web applications. All JSP-compatible servers must support these standards. Filters can be set up toapply to any number of servlets or JSP pages, but not to nonstandard resources. The same goes for Web application security settings.Besides, the tremendous industry support for JSP and servlet technology results in improvements that mitigate many of the criticisms of JSP. For example, the JSP Standard Tag Library and the JSP 2.0 expression language address two of the most well-founded criticisms: the lack of good iteration constructs and the difficulty of accessing dynamic results without using either explicit Java code or verbose jsp:useBean elements.3. Misconceptions About JSPForgetting JSP Is Server-Side TechnologyHere are some typical questions Marty has received (most of them repeatedly). • Our server is running JDK 1.4. So, how do I put a Swing component in a JSP page?•How do I put an image into a JSP page? I do not know the proper Java I/O commands to read image files.• Since Tomcat does not support JavaScript, how do I make images that are highlighted when the user moves the mouse over them?• Our clients use older browsers that do not understand JSP. What should we do?• When our clients use "View Source" in a browser, how can I prevent them from seeing the JSP tags?All of these questions are based upon the assumption that browsers know something about the server-side process. But they do not. Thus:• For putting applets with Swing components into Web pages, what matters is the browser's Java version—the server's version is irrelevant. If the browser supports the Java 2 platform, you use the normal APPLET (or Java plug-in) tag and would do so even if you were using non-Java technology on the server. • You do not need Java I/O to read image files; you just put the image in the directory for Web resources (i.e., two levels up from WEB-INF/classes) and output a normal IMG tag.•You create images that change under the mouse by using client-side JavaScript, referenced with the SCRIPT tag; this does not change just because the server is using JSP.• Browsers do not "support" JSP at all—they merely see the output of the JSP page. So, make sure your JSP outputs HTML compatible with the browser, just asyou would do with static HTML pages.• And, of course you need not do anything to prevent clients from seeing JSP tags; those tags are processed on the server and are not part of the output that is sent to the client.Confusing Translation Time with Request TimeA JSP page is converted into a servlet. The servlet is compiled, loaded into the server's memory, initialized, and executed. But which step happens when? To answer that question, remember two points:• The JSP page is translated into a servlet and compiled only the first time it is accessed after having been modified.• Loading into memory, initialization, and execution follow the normal rules for servlets.The most frequently misunderstood entries are highlighted. When referring to the table, note that servlets resulting from JSP pages use the _jspService method (called for both GET and POST requests), not doGet or doPost. Also, for initialization, they use the jspInit method, not the init method.JSP page translated into servlet Servlet compiled Servlet loaded into server's memory jspInit called _jspService called.4.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:1.They are known to work well in other applications.2. They are ready to use with the next project.3. They can also be used by other teams in the organization.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 youcan 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.Other types of frameworks:The idea of a framework applies not only to applications but to application componentsas 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 any development 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.Enabling technologies: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.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 connectionis 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 locationof 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 to name 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. (Ignorance is not always bliss.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. Neither approach is 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 locatea 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.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 serve r 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.5. Java servlets:Sun’s Java Servlet platform directly addresses the two main drawbacks of CGI programs.First, servlets offer better performance and utilization ofresources 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. To learn more about servlet programming, we recommend Java Servlets by Example, by Alan R. Williamson [Williamson]. The definitive source for Servlet information is the Java Servlet Specification [Sun, JST].6. JavaServer Pages:While Java servlets are a big step up from CGI programs, they are not a panacea. To generate 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>");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.7. JavaBeans: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 noargument constructor. JavaBeans expose internal fields as properties byproviding public methods that follow a consistent design pattern. Knowing that the property names follow this pattern, other Java classes 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 flavor s of methods: accessors are used to read a JavaBean’s state; mutators are used 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 bepublic 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.。
JSP技术 ppt课件
JSP技术
getParameterNames()：返回所有提交的参数名称。 getCookies()：返回所有的Cookie。 getContextPath()：返回HTTP请求中，指示请求上下 文的部分。
JSPቤተ መጻሕፍቲ ባይዱ术
getHeader(String name)：获取request头信息。 getHeaderNames()：返回所有的request请求名称。
JSP技术
对象request是javax.servlet.ServletRequest类的实 例，代表着客户端的请求。request包含客户端的信息以及 请求的信息，如请求哪个文件，附带的地址栏参数等。每次 客户端请求都会产生一个request实例。客户端的请求信息 被封装在request对象中。这样，在服务端可以通过request 对象，接受所有从浏览器发往服务器的请求内的所有信息， 然后做出响应。request对象是HttpServletRequest接口的 实现，
JSP技术
request隐藏对象中包含了从当前JSP页面的URL查询 字符串得到的信息，从MTHL表单中提交的编码数据也包含 在request请求中。这些信息到了服务器后，服务器会把这 些信息当做Java的String对象，这些String对象用来代表传 递的参数名和参数值。在request隐藏对象访问客户端请求 的参数时，会通过4.2.1小节中介绍的一些方法检索到请求参 数的信息。
JSP技术
访问客户端请求中的参数。 访问客户端请求中的国际化信息。 访问客户端请求中的请求报头。 访问客户端请求中的安全信息。
JSP技术
获取客户端的Cookie信息。 管理请求中的属性。 request隐藏对象中有一些常用的方法，通过这些方法 来实现request隐藏对象的各个功能，这些方法有以下几种 ：
JSP、ASP和ASP .NET技术分析
JSP、ASP和技术分析【摘要】开发一个WEB系统，选取何种开发工具显得尤为重要。
在科技迅猛发展的今天，可供选择的开发工具越来越多，本文以JSP、ASP、 举例，对三种技术进行介绍和比较，从而找出适合实际系统开发需要的工具。
【关键词】ASP；JSP；1 JSP技术介绍JSP（Java Server Page）作为当今主流动态网页设计平台之一，是由SUN公司发起的并联合多家公司共同创立的一种动态网页设计技术标准。
JSP的基础是Java技术，因为其运行于虚拟机之上，所以一般用来设计多平台和跨服务器的动态页面。
JSP的执行方式和常见的VBSeript和JavaScript有所不同，它的执行是完全在服务器端的，而其他的脚本语言执行中，一部分是在浏览器上执行的。
在静态HTML页面内加入Java脚本片断和标记（tag）就构成了JSP页面。
当服务器收到访问JSP页面的请求时，先执行其的java程序段，之后将执行的结果以HTML页面的形式展现在浏览器端。
随着Java Server的发展和JSP的日趋成熟，应用Java语言进行Web开发的技术逐渐崭露头角。
从本质上来讲JSP就是Java程序的延伸，是一种特殊应用的Java语句段，在此基础上加入了一个HTTP Server这个类的引擎，使得某些对象能够自动的初始化方便用户使用，用户从而不用再去花费大量的时间进行前期准备的工作。
现将JSP具有的优点列举如下：（1）JSP采用的脚本语言Java具有是分布式的、面向对象的、解释运行等特点；（2）JSP采用的脚本语言Java去掉了直接处理地址的指针等概念，引入了类和对象等概念；（3）JSP采用Servet（服务器端程序）实现了服务器资源的目的；（4）Java Beans的语法和java非常接近，便于使用；（5）Java中JDBC的数据库连接技术已非常成熟；（6）JSP对XML也有着非常广泛的支持。
当然，在使用的过程中，JSP同样也存在以下缺点：（1）Java的跨平台的功能，使得产品具有很好的伸缩能力的同时，也大大增加了开发相关产品的复杂度；（2）Java程序的执行是通过常驻内存来完成的，这样一来使得内存的使用率大大降低，在多个用户多道任务同时执行的时候会造成内存使用率低的问题；（3）系统的资料较为匮乏。
chapter01 JSP简介
J2EE简介
J2EE是一个是一个使用Java开发分布式企业级 应用的规范。是一种利用Java 2 平台来简化企 业管理解决方案的开发、部署和管理相关复杂 问题的体系结构。 J2EE J2SE Java J2EE体系的核心是J2SE，同时全面支持Java Servlets API、JSP、JavaBean、EJB 、JDBC API、CORBA、XML以及能够在Internet 应用中保护数据的安全模式等新技术。 使得J要求。 我们这里实际是讲一个J2EE的子集JSP。
<Context path=“/moon” docBase=“C:/Game” debug=“0” reloadable=“true”/> 经这样设置，就可以将我们实际运行的 jsp文件如A.jsp实际放在C:Game中，而在 流览其中使用moon目录： 如：http：//127.0.0.1：8090/moon/A.jsp
习题1
7.写出一个完整的创建表格的SQL语句。
create table score ( 学号 VARCHAR2(32) not null, 姓名 VARCHAR2(32), 数学成绩 NUMBER(6), 物理成绩 NUMBER(6), 英语成绩 NUMBER(6) ) ; alter table score add constraint SCORE_PK primary key (学号);
习题1
6.如果想修改Tomcat服务器的端口号，应 该修改那个文件？能否将端口号修改为 80，条件是什么？
JSP是Java Server Pages的简称
JSP是Java Server Pages的简称，就是服务器端的一种基于Java语言的网页技术。
在普通网页中加入若干段程序代码之后放在Web服务器端运行，再将运行的结果向用户发布，用户通过浏览器就能看到精彩纷呈的动态网页了。
在传统的HTML网页文件中加入Java程序片段和一些JSP标记，就可以构成一个jsp网页，其扩展名为.JSP。
实现动态网页原理：Web服务器在遇到JSP网页的请求时，首先执行其中的Java程序片段（红框）通过这些Java程序片段可以操作数据库、发送Email、传输数据信息以及重定向网页等。
（中间）然后服务器将执行完程序后所产生的结果封装到原html网页中，以html的格式返回给用户。
（后两行）JSP技术的特点：将内容的生成和显示分离；使用可重用的组件；采用标识简化页面的开发；具有Java技术所带来的所有优点；容易整合到多种应用体系结构中。
JSP与Java Java的核心技术就是Java虚拟机JVM，“一次编写，多次运行”，是让千百万程序员梦寐以求的口号，这无疑是软件业发展史上的一个划时代的创举。
JSP实质上就是一些JSP标记、Java程序段以及html文件的结合体，它以Java语言作为其内置的脚本语言。
所以说Java有什么功能，JSP就具备同样的功能。
Java的诸多优异性能在JSP上得到了最充分的体现。
搭建JSP的运行环境需要具有JSP引擎的软件包，即JDK+Tomcat。
JDK是Java程序的编译和实时运行环境（设置环境变量），tomcat调用JDK来编译和执行JSP中的Java程序代码，它先执行JSP文件中的Java代码，再将执行的结果封装到HTML网页中，并以HTML格式返回给用户的浏览器。
了解下Servlet，它是运行在JSP服务器端，用来生成web页面的一种Java程序。
JSP页面——JSP引擎——Servlet Java 编译器——Class类文件——Java虚拟机JSP与Servlet之间的关系：JSP代码在服务器端被编译成Servlet，并由Java虚拟机解释执行。
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JSP技术简介
什么是JSP？
JSP（JavaServer Pages）是一种用于创建动态网页的技术。
它允许开发人员将
动态内容（如数据库查询结果或用户输入）嵌入到HTML页面中。
与静态网页不同，JSP页面可以根据不同的请求和数据来生成不同的输出。
JSP是基于Java编程语言的，因此开发人员可以使用Java的强大功能来实现
复杂的业务逻辑。
同时，它也是在服务器端运行的，这意味着用户无需下载任何插件或软件，并且可以通过任何支持HTTP协议的浏览器访问到JSP页面。
JSP的优点
1.易于学习和使用：与其他服务器端技术相比，JSP是学习曲线较为平
缓的。
它是用HTML和Java代码混合编写的，因此对于熟悉HTML和Java
的开发人员来说，上手相对容易。
2.代码重用：JSP页面可以通过组件、标签库和自定义标签等方式实现
代码的重用。
这使得开发人员可以更加高效地开发和维护项目。
3.动态内容生成：JSP允许开发人员在HTML页面中嵌入Java代码，
这使得动态内容的生成变得非常简单。
开发人员可以使用Java的强大功能处理和操作数据，从而提供与用户交互的动态页面。
4.可扩展性：JSP技术是基于Java的，可以与其他Java技术（如
Servlet和EJB）无缝集成。
这使得开发人员能够构建复杂的企业级应用程序，并实现高度的可扩展性。
5.跨平台性：由于JSP是在服务器端运行的，所以它可以在任何支持Java的操作系统上运行。
这意味着开发人员可以使用一套代码在不同的操作
系统上部署应用程序。
JSP的工作原理
JSP的工作原理可以简单概括为以下几个步骤：
1.编写JSP页面：开发人员编写JSP页面，它包含了HTML和Java代码。
Java代码通常使用特殊的标签（<% %>）来标识。
2.编译为Servlet：当第一次访问JSP页面时，容器会将JSP页面编译
成一个Servlet。
这个过程是自动的，开发人员无需手动进行。
3.创建Servlet实例：每次有请求到达JSP页面时，容器都会为该请求
创建一个Servlet实例。
这意味着JSP页面可以处理多个并发请求。
4.执行Servlet代码：容器调用Servlet实例的方法来执行Servlet代码。
这包括Java代码中的任何业务逻辑，以及生成动态内容的过程。
5.生成响应：在执行完Servlet代码后，容器将生成的HTML内容发送
给客户端浏览器，并显示在用户的屏幕上。
JSP的基本语法
JSP使用自己的特殊标签来嵌入Java代码，这些标签的主要有以下几种：
•<% %>：用于插入一段Java代码。
•<%= %>：用于插入Java表达式的值。
•<%! %>：用于在类级别定义成员变量和方法。
•<%––%>：用于添加注释，这些注释不会被输出到客户端。
以下是一个简单的JSP页面的示例：
<html>
<head>
<title>欢迎页面</title>
</head>
<body>
<h1>欢迎来到JSP世界！</h1>
<% int count = 5; %>
<p>当前计数：<%= count %></p>
</body>
</html>
在上面的示例中，我们使用<% %>标签插入了一段Java代码，并在<%= %>标签
中插入了一个Java表达式的值。
最终，页面会显示出一个标题和计数值。
总结
JSP技术是一种用于创建动态网页的重要技术。
它具有易学易用、代码重用、
动态内容生成、可扩展性和跨平台性等优点。
它的工作原理是将JSP页面编译为Servlet，并在每次请求时创建Servlet实例来处理请求。
通过熟悉JSP的基本语法，开发人员可以轻松地使用Java代码创建动态网页，并为用户提供个性化的体验。
希望本文能够帮助您了解JSP技术的基本概念和特点，并且激发您对于JSP的兴趣。
如果您想深入学习JSP技术，可以继续阅读相关的教程和文档，或者参与相关的开发项目，以提升自己的技术能力。