package com.bobohe.socket;

import java.io.*;

import java.net.*;

class UDPServer {

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

        DatagramSocket server = new DatagramSocket(5050);

        byte[] recvBuf = new byte[100];

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

        server.receive(recvPacket);

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

                recvPacket.getLength());

        System.out.println("Hello World!" + recvStr);

        int port = recvPacket.getPort();

        InetAddress addr = recvPacket.getAddress();

        String sendStr = "Hello ! I'm Server";

        byte[] sendBuf;

        sendBuf = sendStr.getBytes();

        DatagramPacket sendPacket = new DatagramPacket(sendBuf, sendBuf.length,

                addr, port);

        server.send(sendPacket);

        server.close();

    }

}

package com.bobohe.socket;

import java.io.*;

import java.net.*;

class UDPClient{

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

        DatagramSocket client = new DatagramSocket();

        String sendStr = "Hello! I'm Client";

        byte[] sendBuf;

        sendBuf = sendStr.getBytes();

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

        int port = 5050;

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

        //发送数据

        client.send(sendPacket);

        byte[] recvBuf = new byte[100];

        DatagramPacket recvPacket

            = new DatagramPacket(recvBuf , recvBuf.length);

        //接收数据

        client.receive(recvPacket);

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

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

        client.close();

    }

}