多个客户端使用Socket通过一个服务器进行交互的小例子

Client：

import java.awt.BorderLayout;import java.awt.Frame;import java.awt.TextArea;import java.awt.TextField;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.EOFException;import java.io.IOException;import java.net.Socket;import java.net.SocketException;import java.net.UnknownHostException;public class ChatClient extends Frame {    private static final long serialVersionUID = 1L;    private Socket socket;// 声明socket对象    private TextArea textArea = new TextArea();// 实例化文本域    private TextField textField = new TextField();// 实例化文本框    private DataOutputStream dos;// 输出字节流    private DataInputStream dis;// 输入字节流    private boolean isConnected;// 标记位，代表是否已经连接上    Thread thread = new Thread(new RecvThread());// 实例化接收其他客户端发送的消息线程    public static void main(String[] args) {        new ChatClient().launchFrame();    }    public void launchFrame() {        setLocation(400, 300);// 设置位置        setSize(500, 500);// 设置大小        add(textArea, BorderLayout.NORTH);        add(textField, BorderLayout.SOUTH);        pack();// 组件自适应窗口        addWindowListener(new WindowAdapter() {// 添加窗口监听器，使用匿名类的方式实现            @Override            public void windowClosing(WindowEvent e) {                disConnect();// 关闭连接                System.exit(0);// 退出            }        });        textField.addActionListener(new TFListener());// 为文本框注册监听事件        setVisible(true);        connect();        thread.start();// 启动线程    }    public void connect() {        try {            socket = new Socket("127.0.0.1", 64444);            dos = new DataOutputStream(socket.getOutputStream());            dis = new DataInputStream(socket.getInputStream());            isConnected = socket.isConnected();            System.out.print("LocalAddress->" + socket.getLocalAddress() + ",LocalPort" + socket.getLocalPort());            System.out.println("succeed connected!");        } catch (UnknownHostException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }    }    // TextField的监听器类    private class TFListener implements ActionListener {        @Override        public void actionPerformed(ActionEvent e) {            String content = textField.getText().trim();            String text = textArea.getText();            if (!"".equals(text))                text += "\n";            text += content;// 将内容重新拼接，主要是取出之前的内容，添加textField中的内容，然后重新显示            textArea.setText(text);            textField.setText("");// 将textField文本框置空            try {                dos.writeUTF(content);// 向服务器端输出信息                dos.flush();// 刷新缓冲区            } catch (IOException e1) {                e1.printStackTrace();            }        }    }    public void disConnect() {        try {            if (dos != null)                dos.close();            if (socket != null)                socket.close();        } catch (Exception e) {            e.printStackTrace();            System.out.println(e.getMessage());        }    }    private class RecvThread implements Runnable {        public void run() {            try {                while (isConnected) {                    String str = dis.readUTF();                    textArea.setText(textArea.getText() + str + "\n");                }            } catch (SocketException e) {                System.out.println("Good bye!" + e.getMessage());            } catch (EOFException e) {                System.out.println("Good bye - bye!" + e.getMessage());            } catch (IOException e) {                e.printStackTrace();                System.out.println(e.getMessage());            }        }    }}

Server：

import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.EOFException;import java.io.IOException;import java.net.ServerSocket;import java.net.Socket;import java.net.SocketAddress;import java.util.ArrayList;import java.util.List;public class ChatServer {    static ServerSocket serverSocket;    boolean isStarted = false;// 标志是否启动    List<Client> clients = new ArrayList<ChatServer.Client>();    public static void main(String[] args) {        new ChatServer().start();    }    public void start() {        try {            serverSocket = new ServerSocket(64444);// 在固定的端口上进行监听            isStarted = true;        } catch (IOException e) {            e.printStackTrace();        }        try {            while (isStarted) {                Socket s = serverSocket.accept();// 接受连接请求                SocketAddress remoteSocketAddress = s.getRemoteSocketAddress();                System.out.println(remoteSocketAddress.toString());                System.out.println("a client connected!");                Client c = new Client(s);// 启动一个线程                new Thread(c).start();                clients.add(c);// 加入客户端集合，以便将消息群发给每一个客户端            }        } catch (Exception e) {            System.out.println(e.getMessage());        } finally {            try {                if (serverSocket != null)                    serverSocket.close();            } catch (IOException e) {                e.printStackTrace();            }        }    }    class Client implements Runnable {        private Socket socket;        private boolean connected = false;        private DataInputStream dataInputStream;        private DataOutputStream dataOutputStream;        public Client(Socket s) {            this.socket = s;            try {                dataInputStream = new DataInputStream(socket.getInputStream());                dataOutputStream = new DataOutputStream(socket.getOutputStream());                connected = socket.isConnected();                System.out.println("connected = " + connected);            } catch (IOException e) {                e.printStackTrace();            }        }        @Override        public void run() {            String content = null;            try {                Client client = null;                while (connected) {                    try {                        content = dataInputStream.readUTF();                        System.out.println(content);                        System.out.println("clients.size()=>" + clients.size());                        for (int i = 0; i < clients.size(); i++) {                            client = clients.get(i);                            // 分别向每一个客户端发消息                            if (client != this)                                client.dataOutputStream.writeUTF(content);                        }                    } catch (EOFException e) {                        clients.remove(client);// 将客户端移出集合                        System.out.println(e.getMessage());                        System.out.println("Client closed!");                    }                }            } catch (Exception e) {                System.out.println(e.getMessage());            } finally {                try {                    if (dataInputStream != null)                        dataInputStream.close();                    if (dataOutputStream != null) {                        dataOutputStream.close();                    }                    if (socket != null)                        socket.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }    }}