package com.study.srv.demo18;
import java.io.IOException;
import java.net.*;
/**
 * @version 1.0
 * UDP發(fā)送端
 */
public class Demo11 {
    public static void main(String[] args) throws IOException {
        //1.創(chuàng)建DatagramSocket對象，準備發(fā)送和接收數(shù)據(jù),在9998端口接收
        DatagramSocket datagramSocket = new DatagramSocket(9998);
        //2.將需要發(fā)送的數(shù)據(jù)，封裝到DatagramPacket對象
        String s="發(fā)送的數(shù)據(jù)";
        byte[] buf=s.getBytes();
        InetAddress ip = InetAddress.getByName("192.168.0.18");
        //說明：封裝的DatagramPacket對象
        //buf 內容字節(jié)數(shù)組
        //buf.length 數(shù)據(jù)長度
        //ip 主機（ip）
        //9999 端口
        DatagramPacket packet = new DatagramPacket(buf, buf.length, ip, 9999);
        //發(fā)送數(shù)據(jù)
        datagramSocket.send(packet);
        //關閉資源
//        datagramSocket.close();
        System.out.println("發(fā)送完畢");
        //發(fā)送端變?yōu)榻邮斩私邮諗?shù)據(jù)
        byte[] bytes = new byte[1024];
        DatagramPacket datagramPacket = new DatagramPacket(bytes, bytes.length);
        datagramSocket.receive(datagramPacket);
        int length = datagramPacket.getLength();
        byte[] data = datagramPacket.getData();
        String string = new String(data, 0, length);
        System.out.println(string);
        datagramSocket.close();
        System.out.println("接受結束");
    }
}

package com.study.srv.demo18;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
/**
 * @version 1.0
 *UDP接收端
 */
public class Demo10 {
    public static void main(String[] args) throws IOException {
        //1．創(chuàng)建一個 DatagramSocket對象，準備在9999接收數(shù)據(jù)
        DatagramSocket datagramSocket = new DatagramSocket(9999);
        //2．構建一個DatagramPacket 對象，準備接收數(shù)據(jù)
        //在UDP協(xié)議，一個數(shù)據(jù)包最大64k
        byte[] buf=new byte[1024];
        DatagramPacket packet = new DatagramPacket(buf, buf.length);
        //3.接收方法 將通過網(wǎng)絡傳輸?shù)腄atagramPacket對象填充到packet里去。
        System.out.println("接收端等待接收");
        datagramSocket.receive(packet);
        //4.可以對packet進行拆包，取出數(shù)據(jù)，并顯示
        //實際接收到的數(shù)據(jù)字節(jié)長度
        int length = packet.getLength();
        //實際接收到的數(shù)據(jù)
        byte[] data = packet.getData();
        String string = new String(data, 0, length);
        System.out.println(string);
        //5.關閉資源
//        datagramSocket.close();
        System.out.println("接收結束");
        //接收端變?yōu)榘l(fā)送端，發(fā)送數(shù)據(jù)
        String s="接收端變?yōu)榘l(fā)送端，發(fā)送數(shù)據(jù)";
        byte[] bytes=s.getBytes();
        DatagramPacket datagramPacket = new DatagramPacket(bytes, bytes.length, InetAddress.getByName("192.168.0.18"), 9998);
        datagramSocket.send(datagramPacket);
        datagramSocket.close();
        System.out.println("發(fā)送完畢");
    }
}