Java最简单的UDP实例

服务端: 监听端口（5051）,接收数据

import java.io.*;

import java.net.*;

import java.util.Scanner;

class UdpServer{

    public static void main(String[] args)throws IOException{

        DatagramSocket  server = new DatagramSocket(5051);

  byte[] recvBuf = new byte[100];

  DatagramPacket recvPacket = new DatagramPacket(recvBuf, recvBuf.length);

  while (true) {

   server.receive(recvPacket);

   String recvStr = new String(recvPacket.getData(), 0,

     recvPacket.getLength());

   System.out.println("收到:" + recvStr);

   if(recvStr.endsWith("q")|| recvStr.endsWith("quit")){

    break;

   }

  }

        server.close();

    }

}

 

客户端：向目标IP（127.0.0.1）及端口（5051），发送字符串

import java.io.*;

import java.net.*;

import java.util.Scanner;

class UdpClient{

    public static void main(String[] args)throws IOException{

        DatagramSocket client = new DatagramSocket();

        InetAddress addr = InetAddress.getByName("127.0.0.1");

        int port = 5051;

        byte[] sendBuf;

        while(true){

         Scanner sc = new Scanner(System.in);

         System.out.println("请输要发送的内容：");

         String str  = sc.nextLine();

            sendBuf = str.getBytes();

            DatagramPacket sendPacket = new DatagramPacket(sendBuf , sendBuf.length , addr , port );

         client.send(sendPacket);

   if(str.endsWith("q")|| str.endsWith("quit")){

    break;

   }

        }

  client.close();

 }

}