以下是接收端代码：
package com.udp.test; import sun.security.util.BitArray; import javax.xml.bind.DatatypeConverter; import java.io.IOException; import java.net.DatagramPacket; import java.net.InetAddress; import java.net.InetSocketAddress; import java.net.MulticastSocket; /** * @Author lenovo * @Date 2019/7/18 * @Time 15:57 */ public class MyUdp { /** * 端口 */ private static int port=12501; /** * 接收字节组播 */ private static byte[] receiveBytes=new byte[1024]; /** * 组播地址 */ private static InetAddress address=null; /** * 套解字 */ private static MulticastSocket multicastSocket=null; /** * 用户数据报 */ private static DatagramPacket datagramPacket=null; public static void main(String[] args){ try { multicastSocket=new MulticastSocket(port); multicastSocket.setTimeToLive(254); address=InetAddress.getByName("232.10.8.7"); multicastSocket.joinGroup(address); datagramPacket=new DatagramPacket(receiveBytes,0,1024,address,port); receiveBytes(); System.in.read(); }catch (java.io.IOException ex){ } } /** * 接收数据 */ private static void receiveBytes(){ try { multicastSocket.receive(datagramPacket); byte[] data=datagramPacket.getData(); byte[] validBytes=new byte[datagramPacket.getLength()]; System.arraycopy(data,0,validBytes,0,validBytes.length); String message=DatatypeConverter.printHexBinary(validBytes); InetSocketAddress address=(InetSocketAddress)datagramPacket.getSocketAddress(); System.out.println("来自【"+address.toString()+"】的消息："+message); receiveBytes(); }catch (IOException e){ } } }发送端是C#写的，这里就不贴出来了。
测试结果：
