multicasttimeserver.java

让初学者了解javaUDP的编程及应用

import java.io.*;
import java.net.*;
import java.util.*;
import java.text.DateFormat;
import java.awt.event.*;
import javax.swing.Timer;
import javax.swing.JOptionPane;

public class MulticastTimeServer{
	protected static MulticastSocket socket = null;
 	public static void main(String []args){
	    Timer t = new Timer(3000, new ActionListener(){
	    public void actionPerformed(ActionEvent event) {
		   	try{
		   		MulticastSocket socket = new MulticastSocket(6666);
        		byte[] buf = new byte[128];
        		Date d = new Date();
				String dString = DateFormat.getDateTimeInstance().format(d);
				buf = dString.getBytes();
        		InetAddress group = InetAddress.getByName("230.0.0.1");
        		DatagramPacket packet = new DatagramPacket(buf, buf.length,group, 6666);
        		socket.send(packet);
        		System.out.println("Now is:" + dString);
        		socket.close();
			}catch (IOException e){
				e.printStackTrace();
			}
		}
		});
		    t.start();
		    JOptionPane.showMessageDialog(null,"要结束服务器吗？","MulticastTimeServer",JOptionPane.INFORMATION_MESSAGE);
		    System.exit(0);
	}
}