example1104_udpb.java

使用UDP实现两个进程间的通信 （编写 A 与 B 两个端点的Java程序）

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

public class Example1104_UDPB extends JFrame implements Runnable,ActionListener
{
	JTextField hostcom;
	JTextArea listcom;
	JTextField infocom;

	public Example1104_UDPB()
	{
		super("Example1104_UDPB");
		setBounds(getToolkit().getScreenSize().width/2,0,getToolkit().getScreenSize().width/2,600);

		setDefaultCloseOperation(EXIT_ON_CLOSE);

		Container con=getContentPane();

		Box box1=Box.createHorizontalBox();
		hostcom=new JTextField();
		box1.add(new JLabel("目的主机"));
		box1.add(hostcom);

		listcom=new JTextArea();
		listcom.setEditable(false);		

		Box box2=Box.createHorizontalBox();
		infocom=new JTextField();
		infocom.addActionListener(this);
		box2.add(new JLabel("发送消息"));
		box2.add(infocom);

		con.add(box1,"North");
		con.add(new JScrollPane(listcom),"Center");
		con.add(box2,"South");

		Thread thread=new Thread(this);
		thread.start();

		setVisible(true);
	}

	public void actionPerformed(ActionEvent evt)
	{
		try
		{
			InetAddress host=InetAddress.getByName(hostcom.getText());
			byte[] buff=infocom.getText().getBytes();
			infocom.setText(null);
			infocom.requestFocus();
			listcom.append(InetAddress.getLocalHost()+":\n"+new String(buff)+"\n\n");
			DatagramPacket packet=new DatagramPacket(buff,buff.length,host,6666);
			DatagramSocket socket=new DatagramSocket();
			socket.send(packet);
			socket.close();
		}
		catch (Exception e)
		{
			listcom.append("Exception in sending DatagramPacket!\n\n");
		}
	}

	public void run()
	{
		DatagramPacket packet=null;
		DatagramSocket socket=null;

		try
		{
			byte[] buff=new byte[8192];
			packet=new DatagramPacket(buff,buff.length);
			socket=new DatagramSocket(5555);
		}
		catch (Exception e)
		{
			listcom.append("Exception in creating DatagramPacket and DatagramSocket!\n\n");
		}

		while (true)
		{
			try
			{
				socket.receive(packet);
				InetAddress host=packet.getAddress();
				String info=new String(packet.getData(),0,packet.getLength());
				listcom.append(host+":\n"+info+"\n\n");
			}
			catch (Exception e)
			{
				listcom.append("Exception in receiving DatagramPacket!\n\n");
			}
		}
	}

	public static void main(String[] args)
	{
		new Example1104_UDPB();
	}
}