java's communicate
JAVA网络通信系统的研究与开发论文
毕业设计（论文）中文摘要毕业设计（论文）外文摘要目录1 引言 (1)1.1 课题的研究现状 (1)1.2 课题简介以及设计要求 (2)1.2.1课题简介 (2)1.2.2课题设计要求 (2)1.3 课题的调研 (2)1.4 可行性分析 (2)1.4.1 可行性分析的目的 (2)1.4.2 技术可行性分析 (3)1.4.3 经济可行性分析 (3)1.4.4 操作可行性分析 (3)1.4.5 法律可行性分析 (4)1.5 论文各章简介 (4)2 系统需求分析 (5)2.1 业务流分析 (5)2.2概念结构设计 (5)2.3 数据流分析 (5)2.4 数据字典 (6)2.4.1数据字典 (6)2.4.2处理逻辑说明 (7)3 系统总体设计 (9)3.1 系统开发的原则 (9)3.1.1 面向用户的观点 (9)3.1.2 严格按阶段进行 (9)3.1.3 采用系统的观点处理 (9)3.1.4采用模块化设计方法 (9)3.1.5 整个系统的设计主要采用快速原形法 (9)3.2系统总体功能结构设计 (10)3.2.1 系统代码设计说明 (10)3.2.2 系统设计技术说明 (10)3.2.3 系统总体功能结构 (12)3.3 系统数据库设计 (13)3.4开发环境设计与运行环境设计 (14)3.4.1 开发环境设计 (14)3.4.2 运行环境设计 (15)4 服务器模块设计 (15)4.1 主服务器类设计 (15)4.2 多线程ServerThread类的设计 (16)4.3 用户注册模块 (17)4.4 登录验证模块设计 (17)4.4.1登录线程设计 (17)4.4.2 通知好友上线模块 (18)4.5 好友管理模块 (19)4.5.1 查找好友模块 (19)4.5.2 查看好友资料模块 (19)4.5.3 直接添加好友模块 (19)4.5.4 添加好友模块 (19)4.5.5 添加好友应答模块 (21)4.5.6 删除好友模块 (22)4.6 退出下线模块 (22)5 客户端模块设计 (23)5.1新用户注册模块 (23)5.1.1 注册流程 (23)5.1.2 注册事件监听流程 (23)5.2 用户登录模块 (25)5.2.1 监听登录事件 (26)5.2.2 界面设计 (27)5.2.3 设计过程中遇到的问题 (28)5.3 消息通信模块 (29)5.3.1 发送消息 (30)5.3.2 监听用户操作消息 (32)5.3.3 接收消息 (35)5.3.4 发送文件和接收文件模块 (36)5.4 好友管理模块 (37)5.4.1 查找好友 (37)5.4.2 添加好友 (38)5.4.3 查看资料 (39)5.4.4 删除好友 (39)6用户手册 (40)6.1 系统的运行环境 (40)6.1.1 硬件要求 (40)6.1.2 软件环境 (40)6.2 系统的功能简介 (40)6.3 系统的运行和操作指南 (40)7 系统特色与不足 (42)7.1 系统特色 (42)7.2 系统不足 (42)7.3 设计收获和心得 (42)结论 (44)致谢 (45)参考文献 (46)1 引言1.1 课题的研究现状网络通信在当今信息社会中起着不可或缺的作用，人们可以利用网络通信技术进行即时的信息交流。
Java中英翻译
abstract (关键字) 抽象['.bstr.kt]access vt.访问,存取['.kses]'(n.入口,使用权)algorithm n.算法['.lg.riem]Annotation [java]代码注释[.n.u'tei..n]anonymous adj.匿名的[.'n.nim.s]'(反义：directly adv.直接地,立即[di'rektli, dai'rektli])apply v.应用,适用[.'plai]application n.应用,应用程序[,.pli'kei..n]' (application crash 程序崩溃) arbitrary a.任意的['ɑ:bitr.ri]argument n.参数;争论,论据['ɑ:gjum.nt]'(缩写args)assert (关键字) 断言[.'s.:t] ' (java 1.4 之后成为关键字)associate n.关联(同伴,伙伴) [.'s.u.ieit]attribute n.属性(品质,特征) [.'tribju:t]boolean (关键字) 逻辑的, 布尔型call n.v.调用; 呼叫; [k.:l]circumstance n.事件(环境,状况) ['s.:k.mst.ns]crash n.崩溃,破碎[kr..]cohesion内聚,黏聚,结合[k.u'hi:..n](a class is designed with a single, well-focoused purpose. 应该不止这点) command n. 命令,指令[k.'mɑ:nd](指挥, 控制) (command-line 命令行)Comments [java]文本注释['k.ments]compile [java] v.编译[k.m'pail]' Compilation n.编辑[,k.mpi'lei..n] const (保留字)constant n. 常量, 常数, 恒量['k.nst.nt]continue (关键字)coupling耦合,联结['k.pli.]making sure that classes know about other classes only through their APIs. declare [java]声明[di'kl..]default (关键字) 默认值; 缺省值[di'f.:lt]delimiter定义符; 定界符Encapsulation[java]封装(hiding implementation details)Exception [java]例外; 异常[ik'sep..n]entry n.登录项, 输入项, 条目['entri]enum (关键字)execute vt.执行['eksikju:t]exhibit v.显示, 陈列[ig'zibit]exist存在, 发生[ig'zist] '(SQL关键字exists)extends (关键字) 继承、扩展[ik'stend]false (关键字)final (关键字) finally (关键字)fragments段落; 代码块['fr.gm.nt]FrameWork [java]结构,框架['freimw.:k]Generic [java]泛型[d.i'nerik]goto (保留字) 跳转heap n.堆[hi:p]implements (关键字) 实现['implim.nt]import (关键字) 引入(进口,输入)Info n.信息(information [,inf.'mei..n] )Inheritance [java]继承[in'herit.ns] (遗传,遗产)initialize预置初始化[i'iz]instanceof (关键字) 运算符，用于引用变量，以检查这个对象是否是某种类型。
蓝桥17JavaSE面试题及其参考答案
蓝桥JavaSE面试题总结目录第一章初识Java (1)1.Java跨平台原理（字节码文件、虚拟机） (1)2.Java的安全性 (1)3.Java三大版本 (2)4.Java开发运行过程 (2)5.Java开发环境配置 (2)6.什么是JVM？什么是JDK？什么是JRE？ (2)7.Java三种注释类型 (3)第二章数据类型和运算符 (4)1.8种基本数据类型及其字节数 (4)2.i++和++i的异同之处 (4)3.&和&&的区别和联系，|和||的区别和联系 (5)4.用最有效率的方法算出2乘以8等于多少 (5)5.基本数据类型的类型转换规则 (5)第三章流程控制 (7)1.三种流程控制结构 (7)2.if多分支语句和switch多分支语句的异同之处 (7)3.while和do-while循环的区别 (7)4.break和continue的作用 (7)5.请使用递归算法计算n！ (8)6.递归的定义和优缺点 (8)第四章数组 (9)1.数组的特征 (9)2.请写出冒泡排序代码 (9)3.请写出选择排序的代码 (10)4.请写出插入排序的代码 (10)5.可变参数的作用和特点 (11)第五章面向对象 (12)1.类和对象的关系 (12)2.面向过程和面向对象的区别 (12)3.方法重载和方法重写（覆盖）的区别 (12)4.this和super关键字的作用 (13)5.static关键字的作用（修饰变量、方法、代码块） (13)6.final和abstract关键字的作用 (13)7.final、finally、finalize的区别 (14)8.写出ng.Object类的六个常用方法 (14)9.private/默认/protected/public权限修饰符的区别 (14)10.继承条件下构造方法的执行过程 (15)11.==和equals的区别和联系 (15)12.多态的技能点（前提条件，向上转型、向下转型） (16)13.接口和抽象类的异同之处 (16)14.简述Java的垃圾回收机制 (16)第六章异常处理 (18)1.Error和Exception的区别 (18)2.Checked异常和Runtime异常的区别 (18)3.Java异常处理try-catch-finally的执行过程 (18)4.异常处理中throws和throw的区别 (19)第七章常用工具类 (20)1.基本数据类型和包装类 (20)2.Integer与int的区别 (20)3.String类为什么是final的 (21)4.String、StringBuffer、StringBuilder区别与联系 (21)5.String类型是基本数据类型吗？基本数据类型有哪些 (21)6.String s="Hello";s=s+"world!";执行后，s内容是否改变？ (21)7.String s = new String("xyz");创建几个String Object? (22)8.下面这条语句一共创建了多少个对象：String s="a"+"b"+"c"+"d"; (22)9.java.sql.Date和java.util.Date的联系和区别 (23)10.使用递归算法输出某个目录下所有文件和子目录列表 (23)第八章集合 (25)1.Java集合体系结构（List、Set、Collection、Map的区别和联系） (25)2.Vector和ArrayList的区别和联系 (26)3.ArrayList和LinkedList的区别和联系 (26)4.HashMap和Hashtable的区别和联系 (26)5.HashSet的使用和原理（hashCode()和equals()） (26)6.TreeSet的原理和使用（Comparable和comparator） (27)7.集合和数组的比较（为什么引入集合） (27)8.Collection和Collections的区别 (27)第九章IO流 (28)1.输入流和输出流联系和区别，节点流和处理流联系和区别 (28)2.字符流字节流联系区别；什么时候使用字节流和字符流? (28)3.列举常用字节输入流和输出流并说明其特点，至少5对。
Java面试中最经常被问到的问题
Java面试中最经常被问到的问题1. What is the difference between an Applet and an Application?2. What are java beans?3. What is RMI?4. What gives java it's "write once and run anywhere" nature?5. How does Java inheritance work?6. What are native methods? How do you use them?7. Class A subclass B subclass C. All override foo(). I cast C to A and call foo(). What happens? C an C call A->foo()?8. What does the "static" keyword mean in front of a variable? A method? A class? Curly braces {}?9. How many different types of JDBC drivers are present? Discuss them.10. Does Java have "goto"?11. Why "bytecode"? Can you reverse-engineer the code from bytecode?12. How does exception handling work in Java?13. Does Java have destructors?14. What does the "final" keyword mean in front of a variable? A method? A class?15. Access specifiers: "public", "protected", "private", nothing?3. What is RMI?4. What gives java it's "write once and run anywhere" nature?5. How does Java inheritance work?6. What are native methods? How do you use them?7. Class A subclass B subclass C. All override foo(). I cast C to A and call foo(). What happens? C an C call A->foo()?8. What does the "static" keyword mean in front of a variable? A method? A class? Curly braces {}?9. How many different types of JDBC drivers are present? Discuss them.10. Does Java have "goto"?11. Why "bytecode"? Can you reverse-engineer the code from bytecode?12. How does exception handling work in Java?13. Does Java have destructors?14. What does the "final" keyword mean in front of a variable? A method? A class?15. Access specifiers: "public", "protected", "private", nothing?1. What is the difference between an Applet and an Application?A Java application is made up of a main() method declared as public static void that accepts a string array argument, along with any other classes that main() calls. It lives in the environment that the host OS provides.A Java applet is made up of at least one public class that has to be subclassed from java.awt. Applet. The applet is confined to living in the user's Web browser, and the browser's security rules, (or Sun's appletviewer, which has fewer restrictions).The differences between an applet and an application are as follows:1. Applets can be embedded in HTML pages and downloaded over the Internet whereas Applicatio ns have no special support in HTML for embedding or downloading.2. Applets can only be executed inside a java compatible container, such as a browser or appletvie wer whereas Applications are executed at command line by java.exe or jview.exe.3. Applets execute under strict security limitations that disallow certain operations(sandbox model security) whereas Applications have no inherent security restrictions.4. Applets don't have the main() method as in applications. Instead they operate on an entirely diff erent mechanism where they are initialized by init(),started by start(),stopped by stop() or destroye d by destroy().2. What are java beans?JavaBeans is a portable, platform-independent component model written in the Java programming language, developed in collaboration with industry leaders. It enables developers to write reusable components once and run them anywhere -- benefiting from the platform-independent power of Ja va technology. JavaBeans acts as a Bridge between proprietary component models and provides a seamless and powerful means for developers to build components that run in ActiveX container ap plications.Java beans is very powerful tool you can use in your servlet/JSP bridge. You can use the servlets t o build the bean and can be passed over to the JSP for reading. This provides tight encapsulation o f the data while preserving the sanctity of servlets and JSP.3. What is RMI?RMI stands for Remote Method Invocation. Traditional approaches to executing code on other ma chines across a network have been confusing as well as tedious and error-prone to implement. The nicest way to think about this problem is that some object happens to live on another machine, an d that you can send a message to the remote object and get a result as if the object lived on your lo cal machine. This simplification is exactly what Java Remote Method Invocation (RMI) allows yo u to do.4. What gives java it's "write once and run anywhere" nature?Java is compiled to be a byte code which is the intermediate language between source code and m achine code. This byte code is not platorm specific and hence can be fed to any platform. After bei ng fed to the JVM, which is specific to a particular operating system, the code platform specific m achine code is generated thus making java platform independent.5. How does Java inheritance work?A class can only directly extend one class at a time. Multiple inheritance is only allowed with rega rd to interfaces. A class can implement many interfaces. But a class can only extend one non-interf ace class.6. What are native methods? How do you use them?Native methods are used when the implementation of a particular method is present in language ot her than Java say C, C++.To use the native methods in java we use the keyword nativepublic native method_a()This native keyword is signal to the java compiler that the implementation of this method is in a la nguage other than java.Native methods are used when we realize that it would take up a lot of rework to write that piece o f already existing code in other language to java.7. Class A subclass B subclass C. All override foo(). I cast C to A and call foo(). What happens? C an C call A->foo()?An instance of Class C is of type Class B and A (both). SO you can cast C to A. You CANNOT ca st an instance of A to C.8. What does the "static" keyword mean in front of a variable? A method? A class? Curly braces {}?-- static variables: These are class level variable whose value remain same irrespective of the num ber of instances of the class.-- static methods:These are those methods that can be called without the need for creating the objects of the class i.e . they are class level methods. They can call only static methods. They cannot refer to "this" as the y are not associated with any particular instance.-- static block: These are called before the main is called and are called only once. Subsequent inv ocation of the java program containing static block would not call it again. Hence, they can be use d to load libraries say in native function call.-- Only Inner class could be declared as a "static". This declaration suppress the generation of the r eference to the outer class object. 这意味着：1）为创建一个static内部类的对象，我们不需要一个外部类对象；2）不能从static内部类对象访问一个外部类对象。
程序员的英语知识
程序员的英语知识Programmer's English knowledge includes:- Programming languages: Programmers need to be familiar with the syntax and keywords of different programming languages such as Java, C++, Python, etc.- Technical jargon: Programmers need to understand and use technical terms related to coding, algorithms, data structures, and software development.- Documentation: Programmers read and write technical documentation, including software requirements, specifications, design documents, and user manuals.- Communication: Programmers need to effectively communicate with clients, team members, and stakeholders, discussing technical concepts, requirements, and project updates.- Error messages and debugging: Programmers need to understand and interpret error messages to identify and fix software bugs.- Frameworks and libraries: Programmers need to understand documentation and tutorials for various frameworks and libraries used in software development.- API integration: Programmers need to read and understand API documentation to integrate external services or code with their software.- Online resources: Programmers often need to search for and read technical articles, tutorials, and forums to learn new concepts, troubleshoot issues, or find solutions to programming problems. - Version control systems: Programmers should be familiar with terms and commands used in version control systems such as Git, including branch, merge, commit, push, and pull.- Code reviews: Programmers need to understand feedback from code reviews, which may involve identifying and fixing issuesrelated to coding standards, security, performance, and maintainability.。
初识计算机英语作文高中
初识计算机英语作文高中Title: Introduction to Computer Science。
In the era of rapid technological advancement, computer science has emerged as a crucial field, shaping various aspects of our lives. As a high school student venturing into the realm of computer science, one embarks on a journey filled with innovation, problem-solving, and boundless opportunities.First and foremost, delving into computer science introduces one to the fundamental concepts of programming languages. From the ubiquitous Python to the robust Java, understanding these languages empowers individuals to communicate with computers effectively. Learning to code not only enhances logical thinking but also fosters creativity by enabling the creation of software solutions to real-world problems.Moreover, computer science extends beyond mere coding;it encompasses the exploration of algorithms and data structures. These are the building blocks of computational problem-solving, enabling efficient manipulation and organization of vast amounts of data. Through studying algorithms, students develop analytical skills essentialfor optimizing processes and developing scalable solutions.Furthermore, a comprehensive understanding of computer science involves exploring the theoretical underpinnings of computing. Concepts such as computational theory, automata theory, and complexity theory provide insights into the capabilities and limitations of computing systems. By grasping these theoretical concepts, students gain a deeper appreciation for the principles governing modern computing.In addition to theory, practical applications play a pivotal role in computer science education. Projects ranging from developing simple applications to tackling complex problems allow students to apply theoretical knowledge to real-world scenarios. Engaging in hands-on projects not only reinforces learning but also nurtures problem-solving skills and encourages innovation.Beyond the technical aspects, computer science education fosters interdisciplinary connections. The intersection of computer science with fields such as mathematics, engineering, and biology opens doors to diverse career paths and research opportunities. Whetherit's designing algorithms for genomic analysis or developing artificial intelligence for autonomous systems, the interdisciplinary nature of computer science offers endless avenues for exploration.Moreover, the study of computer science instills essential skills for the 21st-century workforce. In an increasingly digital world, proficiency in technology is highly sought after across various industries. The ability to adapt to new technologies, collaborate in teams, and communicate technical concepts effectively are invaluable skills that computer science education cultivates.Furthermore, delving into computer science nurtures a mindset of lifelong learning and adaptability. Given the rapid pace of technological innovation, staying abreast ofadvancements is imperative. Whether it's exploring emerging technologies like blockchain and quantum computing or mastering new programming languages, the journey of learning in computer science is perpetual.In conclusion, embarking on the journey of computer science in high school opens doors to a world of opportunities and growth. From mastering programming languages to exploring theoretical concepts and engaging in practical projects, the study of computer science equips individuals with essential skills and insights for success in the digital age. As one delves deeper into this dynamic field, the possibilities are limitless, and the journey of discovery is perpetual.。
java串口通信
java串口通信API说明java串口通信Java提供了 CommunicationAPI(包含于m包中)用于通过与机器无关的方式，控制各种外部设备。
Communications API，是标准的Java的扩展部分，它在JavaAPI中是没有附带的。
因此，必须先在SUN公司网站的Java站点()上下载这个扩展类库。
1.1Communications API 简介Communications API 的核心是抽象的CommPort类及其两个子类：SerialPort类和ParallePort类。
其中，SerialPort类是用于串口通信的类，ParallePort类是用于并行口通信的类。
CommPort类还提供了常规的通信模式和方法，例如:getInputStream( )方法和getOutputStream( )方法，专用于与端口上的设备进行通信。
然而，这些类的构造方法都被有意的设置为非公有的(non-public)。
所以，不能直接构造对象，而是先通过静态的CommPortIdentifer.getPortIdentifiers()获得端口列表；再从这个端口列表中选择所需要的端口，并调用CommPortIdentifer对象的Open( )方法，这样，就能得到一个CommPort对象。
当然，还要将这个CommPort对象的类型转换为某个非抽象的子类，表明是特定的通讯设备。
该子类可以是SerialPort类和ParallePort类中的一个。
下面将分别对CommPort类，CommPortIdentifier类，串口类SerialPort进行详细的介绍。
1.2 CommPortIdentifier类CommPortIdentifier类的方法如下：方法说明addPortName(String, int, CommDriver) 添加端口名到端口列表里addPortOwnershipListener(CommPortOwnershipListener) 添加端口拥有的监听器removePortOwnershipListener(CommPortOwnershipListener) 移除端口拥有的监听器getCurrentOwner() 得到当前占有端口的对象或应用程序getName() 得到端口名称getPortIdentifier(CommPort) 得到参数打开的端口的CommPortIdentifier类型对象getPortIdentifier(String) 得到以参数命名的端口的CommPortIdentifier类型对象getPortIdentifiers() 得到系统中的端口列表getPortType() 得到端口的类型isCurrentlyOwned() 判断当前端口是否被占用open(FileDescriptor) 用文件描述的类型打开端口open(String, int) 打开端口,两个参数：程序名称,延迟时间(毫秒数)1.3 SerialPort类SerialPort关于串口参数的静态成员变量成员变量说明成员变量说明成员变量说明DATABITS_5 数据位为5 STOPBITS_2 停止位为2 PARITY_ODD 奇检验DATABITS_6 数据位为6 STOPBITS_1 停止位为1 PARITY_MARK 标记检验DATABITS_7 数据位为7 STOPBITS_1_5 停止为1.5 PARITY_NONE 空格检验DATABITS_8 数据位为8 PARITY_EVEN 偶检验 PARITY_SPACE 无检验SerialPort对象的关于串口参数的函数方法说明方法说明getBaudRate() 得到波特率 getParity() 得到检验类型getDataBits() 得到数据位数 getStopBits() 得到停止位数setSerialPortParams(int, int, int, int) 设置串口参数依次为(波特率,数据位,停止位,奇偶检验)SerialPort关于事件的静态成员变量成员变量说明成员变量说明BI Break interrupt中断 FE Framing error错误CD Carrier detect载波侦听 OE Overrun error错误CTS Clear to send清除以传送 PE Parity error奇偶检验错误DSR Data set ready数据备妥 RI Ring indicator响铃侦测DATA_AVAILABLE 串口中的可用数据 OUTPUT_BUFFER_EMPTY 输出缓冲区空SerialPort中关于事件的方法方法说明方法说明方法说明isCD() 是否有载波 isCTS() 是否清除以传送 isDSR() 数据是否备妥isDTR() 是否数据端备妥 isRI() 是否响铃侦测 isRTS() 是否要求传送addEventListener(SerialPortEventListener) 向SerialPort对象中添加串口事件监听器removeEventListener() 移除SerialPort对象中的串口事件监听器notifyOnBreakInterrupt(boolean) 设置中断事件true有效,false 无效notifyOnCarrierDetect(boolean) 设置载波监听事件true有效,false无效notifyOnCTS(boolean) 设置清除发送事件true有效,false无效notifyOnDataAvailable(boolean) 设置串口有数据的事件true有效,false无效notifyOnDSR(boolean) 设置数据备妥事件true有效,false无效notifyOnFramingError(boolean) 设置发生错误事件true有效,false无效notifyOnOutputEmpty(boolean) 设置发送缓冲区为空事件true有效,false无效notifyOnParityError(boolean) 设置发生奇偶检验错误事件true 有效,false无效notifyOnRingIndicator(boolean) 设置响铃侦测事件true有效,false无效getEventType() 得到发生的事件类型返回值为int型sendBreak(int) 设置中断过程的时间，参数为毫秒值setRTS(boolean) 设置或清除RTS位setDTR(boolean) 设置或清除DTR位SerialPort中的其他常用方法方法说明close() 关闭串口getOutputStream() 得到OutputStream类型的输出流getInputStream() 得到InputStream类型的输入流一年半前在jbuilder2006下写过串口通信程序，最近做一个GPS-SMS 项目，用到串口通信，在JBUILDER 配置了comm.jar却发现找不到端口，经过几番查找才发现自己配置的路径错了，浪费了不少时间，有必要记下来，防止下次出错，此次还暴露了自己看文章一目十行，走马观花的毛病。
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