UDP实现消息发送

UDP

发短信，不用连接，需要知道对方地址。

发送端

package com.zr.lesson03;

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

//不需要连接服务器
public class UdpSendDemo01 {
    public static void main(String[] args) throws Exception {
        //建立一个socket
        DatagramSocket socket = new DatagramSocket();
        //键个包
        String msg = "你好啊";
        //发送给谁
        InetAddress localhost = InetAddress.getByName("localhost");
        int port = 9090;
        DatagramPacket packet = new DatagramPacket(msg.getBytes(),0,msg.getBytes().length,localhost,port);

        //发送包
        socket.send(packet);

        socket.close();
    }
}

接收端

package com.zr.lesson03;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

public class UdpRecelveDemo01 {
    public static void main(String[] args) throws Exception {
        //开放端口
        DatagramSocket socket = new DatagramSocket(9090);
        //接收数据包
        byte[] buffer = new byte[1024];
        DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);
        //阻塞接收
        socket.receive(packet);
        System.out.println(packet.getAddress());
        System.out.println(new String(packet.getData(),0,packet.getLength()));
        socket.close();
    }
}