以下程式碼參考馬士兵的聊天專案，先執行ChatServer.java實現埠監聽，然後再執行ChatClient.java

客戶端例項

ChatClient.java

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;

public class ChatClient extends Frame {
	Socket s = null;
	DataOutputStream dos = null;
	DataInputStream dis = null;
	private boolean bConnected = false;

	TextField tfTxt = new TextField();

	TextArea taContent = new TextArea();

	Thread tRecv = new Thread(new RecvThread());

	public static void main(String[] args) {
		new ChatClient().launchFrame();
	}

	public void launchFrame() {
		setLocation(400, 300);
		this.setSize(300, 300);
		add(tfTxt, BorderLayout.SOUTH);
		add(taContent, BorderLayout.NORTH);
		pack();
		this.addWindowListener(new WindowAdapter() {

			@Override
			public void windowClosing(WindowEvent arg0) {
				disconnect();
				System.exit(0);
			}

		});
		tfTxt.addActionListener(new TFListener());
		setVisible(true);
		connect();

		tRecv.start();
	}

	public void connect() {
		try {
			s = new Socket("localhost", 8888);
			dos = new DataOutputStream(s.getOutputStream());
			dis = new DataInputStream(s.getInputStream());
			System.out.println("connected!");
			bConnected = true;
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}

	}

	public void disconnect() {
		try {
			dos.close();
			dis.close();
			s.close();
		} catch (IOException e) {
			e.printStackTrace();
		}

		/*
		 * try { bConnected = false; tRecv.join(); } catch(InterruptedException
		 * e) { e.printStackTrace(); } finally { try { dos.close(); dis.close();
		 * s.close(); } catch (IOException e) { e.printStackTrace(); } }
		 */
	}

	private class TFListener implements ActionListener {

		public void actionPerformed(ActionEvent e) {
			String str = tfTxt.getText().trim();
			// taContent.setText(str);
			tfTxt.setText("");

			try {
				// System.out.println(s);
				dos.writeUTF(str);
				dos.flush();
				// dos.close();
			} catch (IOException e1) {
				e1.printStackTrace();
			}

		}

	}

	private class RecvThread implements Runnable {

		public void run() {
			try {
				while (bConnected) {
					String str = dis.readUTF();
					// System.out.println(str);
					taContent.setText(taContent.getText() + str + '\n');
				}
			} catch (SocketException e) {
				System.out.println("退出了，bye!");
			} catch (EOFException e) {
				System.out.println("推出了，bye - bye!");
			} catch (IOException e) {
				e.printStackTrace();
			}

		}

	}
}
 

import java.io.*;
import java.net.*;
import java.util.*;

public class ChatServer {
	boolean started = false;
	ServerSocket ss = null;

	List<Client> clients = new ArrayList<Client>();

	public static void main(String[] args) {
		new ChatServer().start();
	}

	public void start() {
		try {
			ss = new ServerSocket(8888);
			started = true;
		} catch (BindException e) {
			System.out.println("埠使用中....");
			System.out.println("請關掉相關程式並重新執行伺服器！");
			System.exit(0);
		} catch (IOException e) {
			e.printStackTrace();
		}

		try {

			while (started) {
				Socket s = ss.accept();
				Client c = new Client(s);
				System.out.println("a client connected!");
				new Thread(c).start();
				clients.add(c);
				// dis.close();
			}
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				ss.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

	class Client implements Runnable {
		private Socket s;
		private DataInputStream dis = null;
		private DataOutputStream dos = null;
		private boolean bConnected = false;

		public Client(Socket s) {
			this.s = s;
			try {
				dis = new DataInputStream(s.getInputStream());
				dos = new DataOutputStream(s.getOutputStream());
				bConnected = true;
			} catch (IOException e) {
				e.printStackTrace();
			}
		}

		public void send(String str) {
			try {
				dos.writeUTF(str);
			} catch (IOException e) {
				clients.remove(this);
				System.out.println("對方退出了！我從List裡面去掉了！");
				// e.printStackTrace();
			}
		}

		public void run() {
			try {
				while (bConnected) {
					String str = dis.readUTF();
					System.out.println(str);
					for (int i = 0; i < clients.size(); i++) {
						Client c = clients.get(i);
						c.send(str);
						// System.out.println(" a string send !");
					}
					/*
					 * for(Iterator<Client> it = clients.iterator();
					 * it.hasNext(); ) { Client c = it.next(); c.send(str); }
					 */
					/*
					 * Iterator<Client> it = clients.iterator();
					 * while(it.hasNext()) { Client c = it.next(); c.send(str);
					 * }
					 */
				}
			} catch (EOFException e) {
				System.out.println("Client closed!");
			} catch (IOException e) {
				e.printStackTrace();
			} finally {
				try {
					if (dis != null)
						dis.close();
					if (dos != null)
						dos.close();
					if (s != null) {
						s.close();
						// s = null;
					}

				} catch (IOException e1) {
					e1.printStackTrace();
				}

			}
		}

	}
}