UDP协议的控制台聊天

UDP的特点是速度快，不安全

UDP的控制台聊天实现的原理是一个发送端，一个接收端，发送端负责发送数据打包，接收端负责拆包，解析，我们用循环分别让发送端和接收端一直运行，并且通过线程让他们异步运行，这样，只要两台电脑上都有这个程序，并设置好端口号和IP，就可以实现控制台聊天了。

代码如下：

import java.io.IOException;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.InetAddress;

import java.net.SocketException;

import java.net.UnknownHostException;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Scanner;

public class Talk {

    // UDP????

    public static void main(String[] args) throws SocketException, Exception {

        // ??????????????

        new Thread(new Runnable() {

            @Override

            public void run() {

                while (true) {

                    try {

                        //本机的端口号设置为8888

                        DatagramSocket ds = new DatagramSocket(8888);

                        byte[] buf = new byte[1024];

                        int length = buf.length;

                        DatagramPacket dp = new DatagramPacket(buf, length);

                        ds.receive(dp);

                        // 拆包

                        InetAddress ip = dp.getAddress();

                        byte[] data = dp.getData();

                        int length1 = dp.getLength();

                        // 设置打印在控制台的格式

                        String s1 = new String(data, 0, length1);

                        SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");

                        String time = sdf.format(new Date());

                        String message = dp.getAddress().getHostAddress()+time+" "+s1;

                        System.out.println(message);

                        ds.close();

                    } catch (SocketException e) {

                        e.printStackTrace();

                    } catch (IOException e) {

                        e.printStackTrace();

                    }

                }

            }

        }).start();

        while (true) {

            //接收端

            DatagramSocket ds = new DatagramSocket();

            // 键盘录入

            Scanner sc = new Scanner(System.in);

            String s = sc.nextLine();

            SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");

            String time = sdf.format(new Date());

            String message = time+" "+s;

            byte[] bytes = message.getBytes();

            int len = bytes.length;

            // 设置对面的端口号和IP，联机的时候需要根据对方电脑设置

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

            int port = 8888;

            // 打包并发送

            DatagramPacket packet = new DatagramPacket(bytes, len, ia, port);

            ds.send(packet);

        }

    }

}