组播 java编程

public class Server {  
 
    public static String GROUP_IP = "239.1.1.1";  
    public static int LISTEN_PORT = 22345;  
  
    public static void run() throws UnknownHostException, IOException {  
        System.out.println("server start.......");  
        MulticastSocket multicastSocket = new MulticastSocket(LISTEN_PORT);
        InetAddress group = InetAddress.getByName(GROUP_IP);
        multicastSocket.joinGroup(group);
        byte[] data = new byte[50];   //未填满空间会被0填充，如果数据长度超出数组则超出的数据被忽略 
        DatagramPacket packet = new DatagramPacket(data, data.length);  
        while (true) {  
            try {  
                multicastSocket.receive(packet);  
                System.out.println(new String(data)+packet.getAddress()+" "+
                 new SimpleDateFormat("yy-mm-dd - HH:mm:ss").format(new Date()));  
            } catch (IOException ex) {  
                JOptionPane.showMessageDialog(null, "multicast error");  
                System.exit(1);  
            }  
        }  
    }  
    
    public static void main(String[] args){
     try{
     Server.run();
     }catch(Exception e){
     e.printStackTrace();
     }
    }
    
}

public class Client {  
 
    public static void run() throws IOException, InterruptedException {  
        System.out.println("client start.......");  
        String name = "ClientID:5";
        MulticastSocket multicastSocket = new MulticastSocket();//其实这里使用DatagramSocket发送packet就行  
        InetAddress group = InetAddress.getByName(Server.GROUP_IP);  
        String msg = "数据 become"+name;
        byte[] data = msg.getBytes();  
        DatagramPacket packet = new DatagramPacket(data, data.length, group, Server.LISTEN_PORT);
        int count =1;
        while (true) {  
            try {  
                multicastSocket.send(packet);  
                System.out.println("send ok ["+name+"]-->"+ count );  
                count++;
                Thread.sleep(10000);  
            } catch (IOException ex) {  
                JOptionPane.showMessageDialog(null, "multicast error");  
                System.exit(1);  
            }  
        }  
    }  
    public static void main(String[] args){
     try{
     Client.run();
     }catch(Exception e){
     e.printStackTrace();
     }
    }
}