package udpServer;

import java.io.*;

import java.net.*;

/**

 * 服务端

 * 1、创建服务+端口

 * 2、准备接受容器  byte数组

 * 3、把接收容器封装成包 DatagramPacket

 * 4、接受数据

 * 5、分析数据

 */

public class server {  

    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("接收：\t" + recvStr);

        int port = recvPacket.getPort();

        InetAddress addr = recvPacket.getAddress();

        String sendStr = "Hello ! 我是服务器";

        byte[] sendBuf;

        sendBuf = sendStr.getBytes();

        DatagramPacket sendPacket

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

        server.send(sendPacket);

        server.close();

    }

}

package udpClient;

import java.io.*;

import java.net.*;

/**

 * 1、创建客户端+端口

 * 2、准备数据 字节数组

 * 3、给数据打包 并指定发送的目的地和端口

 * 4、发送

 * 5、释放

 *

 * 思考 ： 发送有类型的数据  怎么处理 如对象  数字 等等

 */

public class client {

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

        DatagramSocket client = new DatagramSocket();

        String sendStr = "我是客户端";

        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);

        client.send(sendPacket);

        byte[] recvBuf = new byte[100];

        DatagramPacket recvPacket

            = new DatagramPacket(recvBuf , recvBuf.length);

        client.receive(recvPacket);

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

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

        client.close();

    }  

}