Java基于UDP协议的简单通讯实例

一、服务端

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();
}
}

二、客户端

package com.ghs.udp;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;

public class UdpClient {
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 UdpClient() {
init();
}

private void init(){
try {
//发送数据
socket = new DatagramSocket();
sendData = "UDP发送数据";
dataBytes = sendData.getBytes();
packet = new DatagramPacket(dataBytes, dataBytes.length,
InetAddress.getByName("localhost"),PORT);
socket.send(packet);

//接受数据
while(true){
dataBytes = new byte[1024];
packet = new DatagramPacket(dataBytes, dataBytes.length);
socket.receive(packet);
int length = packet.getLength();
if(length>0){
receiveData.append(new String(packet.getData(),0,length));
System.out.println(receiveData);
}
}
} catch (SocketException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
socket.close();
}

public static void main(String[] args) {
new UdpClient();
}
}