基于UDP协议通信的例子

package com.ghs.udp; import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.SocketException; public class UdpServer { private int PORT=5050; private DatagramSocket socket; private DatagramPacket packet; private byte[] dataBytes; private StringBuilder receiveData=new StringBuilder();//保存接收到的数据 private String sendData;//要发送的数据 public UdpServer(){ init(); } private void init(){ try { socket = new DatagramSocket(PORT); dataBytes = new byte[1024]; packet = new DatagramPacket(dataBytes, dataBytes.length); while(true){//循环接收数据 socket.receive(packet); int length = packet.getLength(); if(length>0){//如果数据包不为空，就打印出接收到的数据 receiveData.append(new String(packet.getData(),0,length)); System.out.println(receiveData); //回复消息 sendData = "收到"; dataBytes = sendData.getBytes(); packet = new DatagramPacket(dataBytes, dataBytes.length, packet.getAddress(),packet.getPort()); socket.send(packet); } } } catch (SocketException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } socket.close(); } public static void main(String[] args) { new UdpServer(); } }