一个Java聊天程序服务端和客户端程序，C/S结构，ChatServer 类实现了一个聊天室服务器端， 此类有一个构造器， 在构造器中使用newServerSocket()建立一个Socket 连接。RunServer()方法中运行聊天服务，通过Socket 类的getInetAddress().getHostName() 方法获得主机名， 建立新的ChatHandler 对象实例， 在synchronized (clients)中取得与客户端的同步。内部类ChatHandler 继承了Thread 类，在此线程run()方法中处理一次交谈。Close()方法关闭与客户端的连接。

　　ChatRoom 类继承了Applet，在init()中通过new Frame()创建聊天窗体，并在此窗体中设置窗体布局。在login()方法中，通过new Socket(serverHost, port)建立与服务器的连接，通过new Thread()产生新的聊天线程。在logout()方法中，使用sock.close()关闭连接。-A Java chat server and client service procedures, C/S structure, ChatServer class implements a chat room on the server side, such a constructor, use newServerSocket in the constructor () to create a Socket connection. RunServer () method to run the chat service, (). GetHostName () method to get the host name through the Socket class getInetAddress, create a new ChatHandler object instance, to synchronize with the client synchronized (clients) in. Internal class ChatHandler inherited Thread class, in this thread run () method of processing a conversation. Close () method closes the connection with the client. ChatRoom class inherits Applet, () to create a chat window by new Frame init () in, and set the form layout in this form. In the login () method to establish a connection with the server via new Socket (serverHost, port), to generate new chat thread through new Thread (). In the logout () method, using sock.close () closes the connection.