example1205_multicastserver.java

java网络编程中的组播通信

import java.net.*;

public class Example1205_MulticastServer extends Thread
{
	String mes = "Hello, everyone!";
	String host = "228.5.6.7";
	int port = 6789;
	InetAddress group = null;
	MulticastSocket socket = null;
	
	public Example1205_MulticastServer()
	{
		try
		{
			group = InetAddress.getByName(host);
			socket = new MulticastSocket(port);
			socket.setTimeToLive(1);
			socket.joinGroup(group);
		}
		catch (Exception e)
		{
			System.out.println("Error:"+e);
		}
	}
	
	public void run()
	{
		while (true)
		{
			try
			{
				DatagramPacket packet = null;
				byte data[] = mes.getBytes();
				packet = new DatagramPacket(data,data.length,group,port);
				System.out.println("send: " + new String(data));
				socket.send(packet);
				sleep(2000);
			}			
			catch (Exception e)
			{
				System.out.println("Error:" + e);
			}
		}
	}
	
	public static void main(String[] args)
	{
		Example1205_MulticastServer ms = new Example1205_MulticastServer();
		ms.start();
	}
}