Java网络编程UDP实现消息发送及聊天

package com.kuang.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 UdpSenderDemo01 {
    public static void main(String[] args) throws Exception {
        //1、建议一个Socket
        DatagramSocket socket = new DatagramSocket();

        //2、建立包
        String msg = "你好啊，服务器!";
        InetAddress localhost = InetAddress.getByName("localhost");
        int port = 9090;

        //数据、数据的长度起始，要发送给谁
        DatagramPacket packet = new DatagramPacket(msg.getBytes(),0,msg.getBytes().length,localhost,port);

        //3、发送包
        socket.send(packet);

        //4、关闭流
        socket.close();
    }
}

package com.kuang.lesson03;

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

// 不是服务端，但是还是要等待客户端的连接。
// 也就是说只有存在这个才能获得客户端发来的消息
public class UdpReceiveDemo01 {
    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);

        socket.receive(packet);//阻塞接收

        System.out.println(packet.getAddress().getHostAddress());
        System.out.println(new String(packet.getData(),0,packet.getLength()));

        //关闭连接
        socket.close();
    }
}

package com.kuang.chat;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketException;

public class UdpSenderDemo01 {
    public static void main(String[] args) throws Exception {
        DatagramSocket socket = new DatagramSocket(8888);

        //准备数据，控制台读取System.in
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        while (true) {
            String data = reader.readLine();
            byte[] datas = data.getBytes();
            DatagramPacket packet = new DatagramPacket(datas,0,datas.length,new InetSocketAddress("localhost",6666));

            socket.send(packet);
            if (data.equals("bye")) {
                break;
            }
        }
        socket.close();
    }
}

package com.kuang.chat;

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

public class UdpReceiveDemo01 {
    public static void main(String[] args) throws Exception {
        DatagramSocket socket = new DatagramSocket(6666);
        while (true) {
            //准备接收数据
            byte[] container = new byte[1024];
            DatagramPacket packet = new DatagramPacket(container,0,container.length);
            socket.receive(packet);//阻塞式接受包裹

            //断开连接 bye
            byte[] data = packet.getData();
            String receiveData = new String(data,0,data.length);

            System.out.println(receiveData);
            if (receiveData.equals("bye")) {
                break;
            }
        }
        socket.close();
    }
}