简单的消息发送

实现过程：
包括四个类：1,ChatClient:输入用户名，启动客户端子线程。2，ClientThread:根据用户名与服务端连接，接收服务端转发的消息并显示。
3,ChatServer:监听客户端请求，交给服务端子线程处理。4,ServerThread:处理客户端输入/输出和消息转发任务，在构造函数中在第一次建立连接时读取客户端发送的用户名并将其添加到客户端列表

 package com.test.example;import java.io.*;import java.net.*;public class ChatClient {  public static void main(String[] args) {// TODO Auto-generated method stubtry{ClientThread client = new ClientThread(args[0]) ;client.start() ;BufferedReader br = new BufferedReader(new InputStreamReader(System.in)) ;//读取键盘输入String readline ;while((readline = br.readLine()) != null){if(readline.equals("bye")){client.close() ;System.exit(0) ;}client.send(readline) ;}}catch(IOException e){e.printStackTrace() ;}}}package com.test.example;import java.io.*;import java.net.*;public class ClientThread extends Thread {Socket socket ;BufferedReader br ;PrintWriter pw ;//启动客户端public ClientThread(String username){try{//连接服务端socket = new Socket("localhost", 12345) ;br = new BufferedReader(new InputStreamReader(socket.getInputStream())) ;pw = new PrintWriter(socket.getOutputStream()) ;//发送用户名pw.println(username) ;pw.flush() ;}catch(IOException e){e.printStackTrace() ;}}//读取从服务端转发来的消息public void run(){try{String readLine ;while((readLine = br.readLine()) != null){System.out.println("消息来自: " + readLine) ;}}catch(IOException e){e.printStackTrace() ;}}//发送消息public void send(String message){pw.println(message) ;pw.flush() ;}//关闭客户端public void close(){try{br.close() ;pw.close() ;socket.close() ;}catch(IOException e){e.printStackTrace() ;}}}package com.test.example;import java.io.*;import java.util.*;import java.net.*;public class ChatServer { public static void main(String[] args) {// TODO Auto-generated method stubServerSocket server = null ;try{server = new ServerSocket(12345) ;System.out.println("服务器启动：" + server.getInetAddress().getHostAddress() + ":" + server.getLocalPort()) ;//客户端列表Hashtable<String, ServerThread> clienList = new Hashtable<String, ServerThread>() ;//监听,处理while(true){Socket socket = server.accept() ;new ServerThread(socket,clienList).start() ;}}catch(IOException e){e.printStackTrace() ;}finally{try{server.close() ;}catch(IOException e){e.printStackTrace() ;}}}}package com.test.example;import java.io.*;import java.util.*;import java.net.*;public class ServerThread extends Thread {Socket socket ;BufferedReader br ;PrintWriter pw ;Hashtable<String, ServerThread> clientlist ;         //客户端列表String username ;                                   //用户名public ServerThread(Socket socket, Hashtable<String, ServerThread> clientlist){this.socket = socket ;this.clientlist = clientlist ;try{br = new BufferedReader(new InputStreamReader(socket.getInputStream())) ;pw = new PrintWriter(socket.getOutputStream()) ;//读取用户名this.username = br.readLine() ;clientlist.put(username, this) ;//显示连接信息System.out.println(username + "连接：" + socket.getInetAddress().getHostAddress() + ":" + socket.getLocalPort()) ;}catch(IOException e){e.printStackTrace() ;}}public void run(){try{//处理客户端输入String line ;while((line = br.readLine()) != null){//用户输入信息System.out.println(username + "发给 " + line) ;System.out.println() ;if(line.equals("bye"))break ;else{//转发消息String []arr = line.split(":") ;if(arr.length == 2){if(clientlist.containsKey(arr[0])){clientlist.get(arr[0]).send(username + ":" + arr[1]) ;}}}}br.close() ;pw.close() ;socket.close() ;}catch(IOException e){e.printStackTrace() ;}}public void send(String message){System.out.println("发给" + username + " " + message) ;pw.println(message) ;pw.flush() ;}}

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