import java.net.*;
import java.io.*;

public class MulticastServer{
	String groupHost="232.0.0.1";  //組播組虛擬IP
	int port=5678;	//端口
	
	public MulticastServer(){
		try{
			MulticastSocket multicastSocket = new MulticastSocket(port); //MulticastSocket實例
		    InetAddress inetAddress = InetAddress.getByName(groupHost); //組地址
		    multicastSocket.joinGroup(inetAddress); //加入到組播組中
		    while (true){
		        byte[] received = new byte[128]; //接收數據緩沖
		        DatagramPacket datagramPacket = new DatagramPacket(received, received.length); //接收數據的數據報
		        multicastSocket.receive(datagramPacket); //接收數據
		        System.out.println(new String(received)); //輸出接收到的數據
		    }
		}
		catch (Exception exception){
			exception.printStackTrace(); //輸出出錯信息
		}
	}
	
	
  	public static void main(String [] arstring){
		new  MulticastServer();   
  	}
}