example1205_multicastclient.java

java网络编程中的组播通信

import java.net.*;

public class Example1205_MulticastClient implements Runnable
{
	int port = 6789;
	String host = "228.5.6.7";
	InetAddress group = null;
	MulticastSocket socket = null;
	Thread thread;
	
	public Example1205_MulticastClient()
	{
		try
		{
			group=InetAddress.getByName(host);
			socket=new MulticastSocket(port);
			socket.joinGroup(group);
			thread = new Thread(this);
			thread.start();
		}
		catch (Exception e)
		{
			System.out.println("Error:"+e);
		}
	}
	
	public void run()
	{
		try
		{
			DatagramPacket packet = null;
			byte data[] = new byte[1024];
			packet = new DatagramPacket(data, data.length);
			socket.receive(packet);
			System.out.println("received: " + new String(packet.getData(), 0, packet.getLength()) + " from " + packet.getSocketAddress());
			socket.leaveGroup(group);
		}			
		catch (Exception e)
		{
			System.out.println("Error:" + e);
		}
	}
	
	public static void main(String[] args)
	{
		Example1205_MulticastClient mc = new Example1205_MulticastClient();
	}
}