用TCP开发多客户端聊天程序

服务器端程序基本结构

public class Server extends JFrame implements Runnable{ 
public Server(){ 
      //服务器端打开端口 
      //服务端开启线程，接受客户端连接
} public void run(){ 
       //不断接受客户端连接 
       while(true){ 
                        //接收客户端连接 
                        //开一个聊天线程给这个客户端 
                        //将该聊天线程对象添加进集合 
                        //聊天线程启动
        }
} 
/*聊天线程类，每连接上一个客户端，就为它开一个聊天线程*/ 
class ChatThread extends Thread{ 
              //负责读取相应 SocketConnection 的信息 
              public void run(){ 
                          while(true){ 
                                  //读取客户端发来的信息 
                                  //将该信息发送给所有其他客户端
         } 
      } 
   }
}

具体代码

import java.awt.*;
import java.io.*;
import java.net.*;
import java.util.ArrayList;
import javax.swing.JFrame;

public class Server extends JFrame implements Runnable {
    private Socket s = null;
    private ServerSocket ss = null;
    private ArrayList clients = new ArrayList();// 保存客户端的线程

    public Server() throws Exception {
        this.setTitle("服务器端");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setBackground(Color.yellow);
        this.setSize(400, 600);
        this.setVisible(true);
        ss = new ServerSocket(9999);// 服务器端开辟端口，接受连接
        new Thread(this).start();// 接受客户连接的死循环开始运行
    }

    public void run() {
        try {
            while (true) {
                s = ss.accept();
                /*
                 * s 就是当前的连接对应的 Socket
                 * 对应一个客户端 该客户端随时可能发信息过来
                 * 必须要接收 另外开辟一个线程，专门为这个 s 服务
                 * 负责接受信息
                 */
                ChatThread ct = new ChatThread(s);
                clients.add(ct);
                ct.start();
            }
        } catch (Exception ex) {}
    }

    class ChatThread extends Thread {// 为某个 Socket 负责接受信息
        private Socket s = null;
        private BufferedReader br = null;
        public PrintStream ps = null;

        public ChatThread(Socket s) throws Exception {
            this.s = s;
            br = new BufferedReader(new InputStreamReader(s.getInputStream()));
            ps = new PrintStream(s.getOutputStream());
        }

        public void run() {
            try {
                while (true) {
                    String str = br.readLine();// 读取该 Socket 传来的信息 
                    sendMessage(str); //将 str 转发给所有客户端
                }
            } catch (Exception ex) {}
        }
    }

    public void sendMessage(String msg) {// 将信息发给所有客户端
        for (int i = 0; i < clients.size(); i++) {
            ChatThread ct = (ChatThread) clients.get(i); 
            // 向 ct 内的 Socket 内写 msg
            ct.ps.println(msg);
        }
    }

    public static void main(String[] args) throws Exception {
        Server server = new Server();
    }
}

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.Socket;
import javax.swing.*;

public class Client extends JFrame implements ActionListener, Runnable {
    private JTextArea taMsg = new JTextArea("以下是聊天记录\n");
    private JTextField tfMsg = new JTextField();
    private Socket s = null;
    private String nickName = null;

    public Client() {
        this.setTitle("客户端");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.add(taMsg, BorderLayout.CENTER);
        tfMsg.setBackground(Color.yellow);
        this.add(tfMsg, BorderLayout.SOUTH);
        tfMsg.addActionListener(this);
        this.setSize(400, 800);
        this.setVisible(true);
        nickName = JOptionPane.showInputDialog("输入昵称");
        try {
            s = new Socket("127.0.0.1", 9999);
            JOptionPane.showMessageDialog(this, "连接成功");
            this.setTitle("客户端：" + nickName);
            new Thread(this).start();
        } catch (Exception ex) {
        }
    }

    public void run() {
        try {
            while (true) {
                InputStream is = s.getInputStream();
                BufferedReader br = new BufferedReader(new InputStreamReader(is));
                String str = br.readLine();// 读 
                taMsg.append(str + "\n");// 添加内容
            }
        } catch (Exception ex) {
        }
    }

    public void actionPerformed(ActionEvent e) {
        try {
            OutputStream os = s.getOutputStream();
            PrintStream ps = new PrintStream(os);
            ps.println(nickName + "说:" + tfMsg.getText());
            tfMsg.setText("");
        } catch (Exception ex) {
        }
    }

    public static void main(String[] args) throws Exception {
        Client client = new Client();
    }
}