Java Multicast在Windows中不起作用

Question

我有这个代码，但它不能在2台不同的计算机上工作，我改变了我的防火墙，但它不起作用。

import java.io.IOException;
import java.lang.management.ManagementFactory;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.rmi.RMISecurityManager;
import java.util.ArrayList;
import java.util.HashMap;

public class TestingDota{

private static String name;
public static void main(String args[]){
    name = args[0];

    final InetAddress group;
    final String address = "230.0.0.1";
    final int port = 9876;
    try{
        group = InetAddress.getByName(address);
    }catch(Exception e){
        e.printStackTrace();
        return;
    }
    HashMap<String, Tupla> map = new HashMap<String,Tupla>();
    try{
        final MulticastSocket socket = new MulticastSocket(port);
        socket.setReuseAddress(true);
        socket.joinGroup(group);
        socket.setTimeToLive(2);
        new Thread(){

            public void run(){
                while(true){
                    String msg = ManagementFactory.getRuntimeMXBean().getName()+ "," + name;
                    DatagramPacket packet = new DatagramPacket(msg.getBytes(), msg.length(), group, port);
                    try {
                        socket.send(packet);
                        Thread.sleep(1000);
                    } catch (IOException e){
                        e.printStackTrace();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                }

            }
        }.start();

        while(true){
            byte[] buf = new byte[512];
            DatagramPacket packet = new DatagramPacket(buf, buf.length);
            socket.receive(packet);
            String msg = new String(packet.getData()).trim();
            int index = msg.indexOf(',');
            String key = msg.substring(0,index);
            String name = msg.substring(index+1, msg.length());
            long time = System.currentTimeMillis();
            if(map.containsKey(key)){
                Tupla t = map.get(key);
                t.time = time;
            }else{
                Tupla t = new Tupla();
                t.name = name;
                t.time = time;
                map.put(key, t);
                mostrar(map);
            }
            int size = map.size();
            ArrayList<String> list = new ArrayList<String>();
            for(String k : map.keySet()){
                Tupla t = map.get(k);
                if(time - t.time> 1500 ){
                    list.add(k);
                }
            }
            for(String x : list) map.remove(x);
            if(size > map.size()){
                mostrar(map);
            }
            Thread.sleep(100);
        }
    }catch(Exception e){
        e.printStackTrace();
    }
}

private static void mostrar(HashMap<String, Tupla> map) {
    for(String k : map.keySet()){
        Tupla t = map.get(k);
        System.out.println(t.name);
    }
    System.out.println();
}

static class Tupla{
    String name;
    long time;
}
}

要运行此程序，请写：$ java TestingDota someName，它适用于同一台计算机中的多个终端，但它不能在不同的计算机上工作

Answer 1

230.0.0.1是reserved multicast address。你不能使用它。