java socket实现全双工通信

单工、半双工和全双工的定义

如果在通信过程的任意时刻，信息只能由一方A传到另一方B，则称为单工。

如果在任意时刻，信息既可由A传到B，又能由B传A，但只能由一个方向上的传输存在，称为半双工传输。

如果在任意时刻，线路上存在A到B和B到A的双向信号传输，则称为全双工。

用swing 做的简单界面 实现了客户端和服务器端全双工通信。

Server端代码：

package cn.cblue.net1;

import java.awt.BorderLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.KeyEvent;

import java.awt.event.KeyListener;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PrintWriter;

import java.net.ServerSocket;

import java.net.Socket;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JScrollPane;

import javax.swing.JTextArea;

import javax.swing.JTextField;

/**

 * @Description: 服务端

 * @author huangzjb [email protected]

 * @Company Digital China

 * @date 2014-6-4 下午02:18:06

 * @version 1.0

 */

public class MyServer extends JFrame implements ActionListener {

	JTextArea jta = null;

	JTextField jtf = null;

	JButton jb = null;

	JPanel jp1 = null;

	JScrollPane jsp = null;

	PrintWriter pw = null;

	public static void main(String[] args) {

		new MyServer();

	}

	public MyServer() {

		jta = new JTextArea();

		jsp = new JScrollPane(jta);

		jtf = new JTextField(10);

		// 注册回车事件

		jtf.addKeyListener(new KeyListener() {

			@Override

			public void keyTyped(KeyEvent e) {

			}

			@Override

			public void keyReleased(KeyEvent e) {

			}

			@Override

			public void keyPressed(KeyEvent e) {

				if (e.getKeyCode() == KeyEvent.VK_ENTER) {

					sendMessage();

				}

			}

		});

		jb = new JButton("发送");

		jb.addActionListener(this);// 注册一个监听事件

		jp1 = new JPanel();

		jp1.add(jtf);

		jp1.add(jb);

		this.add(jsp, BorderLayout.CENTER);

		this.add(jp1, BorderLayout.SOUTH);

		this.setTitle("chat server");

		this.setSize(300, 200);

		this.setVisible(true);

		// 接收从客户端发送过来的消息

		try {

			ServerSocket ss = new ServerSocket(2222);

			Socket s = ss.accept();

			BufferedReader in = new BufferedReader(new InputStreamReader(s

					.getInputStream()));

			pw = new PrintWriter(s.getOutputStream(), true);// 写成pw = new PrintWriter(s.getOutputStream())会有问题

			while (true) {

				String info = in.readLine();

				String str = null;

				if (jta.getText() == null || "".equals(jta.getText())) {

					str = "Server:" + info;

				} else {

					str = jta.getText() + "\r\nServer:" + info;

				}

				jta.setText(str);

				jta.setCaretPosition(jta.getDocument().getLength());

			}

		} catch (IOException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

	}

	// 把信息给客户端

	@Override

	public void actionPerformed(ActionEvent e) {

		// TODO Auto-generated method stub

		if (e.getSource() == jb) {

			sendMessage();

		}

	}

	/**

	 * @Description: 发送消息给客户端

	 * @throws

	 */

	public void sendMessage() {

		String info = jtf.getText();

		pw.println(info);

		pw.flush();

		jtf.setText("");

		if (jta.getText() == null || "".equals(jta.getText())) {

			jta.append("Client:" + info);

		} else {

			jta.append("\r\nClient:" + info);

		}

		jta.setCaretPosition(jta.getDocument().getLength());// 设置滚动条自动滚动

	}

}

Client端代码：

package cn.cblue.net1;

import java.awt.BorderLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.KeyEvent;

import java.awt.event.KeyListener;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PrintWriter;

import java.net.Socket;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JScrollPane;

import javax.swing.JTextArea;

import javax.swing.JTextField;

/**

 * @Description: 客户端

 * @author huangzjb [email protected]

 * @Company Digital China

 * @date 2014-6-4 下午02:18:24

 * @version 1.0

 */

public class MyClient extends JFrame implements ActionListener {

	JTextArea jta = null;

	JTextField jtf = null;

	JButton jb = null;

	JPanel jp1 = null;

	JScrollPane jsp = null;

	PrintWriter pw = null;

	public static void main(String[] args) {

		new MyClient();

	}

	public MyClient() {

		jta = new JTextArea();

		jsp = new JScrollPane(jta);

		jtf = new JTextField(10);

		// 注册回车事件

		jtf.addKeyListener(new KeyListener() {

			@Override

			public void keyTyped(KeyEvent e) {

			}

			@Override

			public void keyReleased(KeyEvent e) {

			}

			@Override

			public void keyPressed(KeyEvent e) {

				if (e.getKeyCode() == KeyEvent.VK_ENTER) {

					sendMessage();

				}

			}

		});

		jb = new JButton("发送");

		jb.addActionListener(this);// 注册一个监听事件

		jp1 = new JPanel();

		jp1.add(jtf);

		jp1.add(jb);

		this.add(jsp, BorderLayout.CENTER);

		this.add(jp1, BorderLayout.SOUTH);

		this.setTitle("chat client");

		this.setSize(300, 200);

		this.setVisible(true);

		// 接收从服务端发送过来的消息

		try {

			Socket s = new Socket("127.0.0.1", 2222);

			BufferedReader in = new BufferedReader(new InputStreamReader(s

					.getInputStream()));

			pw = new PrintWriter(s.getOutputStream(), true);

			while (true) {

				String info = in.readLine();

				String str = null;

				if (jta.getText() == null || "".equals(jta.getText())) {

					str = "Server:" + info;

				} else {

					str = jta.getText() + "\r\nServer:" + info;

				}

				jta.setText(str);

				jta.setCaretPosition(jta.getDocument().getLength());

			}

		} catch (IOException e) {

			e.printStackTrace();

		}

	}

	// 把信息给服务器端

	@Override

	public void actionPerformed(ActionEvent e) {

		if (e.getSource() == jb) {

			sendMessage();

		}

	}

	/**

	 * @Description: 发送消息给服务器端

	 * @throws

	 */

	public void sendMessage() {

			String info = jtf.getText();

			pw.println(info);

			pw.flush();

			jtf.setText("");

			if (jta.getText() == null || "".equals(jta.getText())) {

				jta.append("Client:" + info);

			} else {

				jta.append("\r\nClient:" + info);

			}

			jta.setCaretPosition(jta.getDocument().getLength());// 设置滚动条自动滚动

		}

}