2021-09-27 网络编程(UDP-聊天)

编写一个聊天程序，有收数据的部分，和发数据的部分。这两部分需要同时执行。需要用到多线程技术，一个线程控制收，一个线程控制发.
因为收和发动作是不一致的，所以要定义两个run方法，而且这两个方法要封装到不同的类中。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

class Send implements Runnable {

    private DatagramSocket ds;

    public Send(DatagramSocket ds) {
        this.ds = ds;
    }

    @Override
    public void run() {
        try {
            BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));
            String line;
            while ((line = bufr.readLine()) != null) {
                if ("886".equals(line)) {
                    break;
                }
                byte[] buf = line.getBytes();
                DatagramPacket dp = new DatagramPacket(buf,
                        buf.length, InetAddress.getByName("127.0.0.1"), 10002);
                ds.send(dp);
            }
            ds.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}


class Rece implements Runnable {

    private DatagramSocket ds;

    public Rece(DatagramSocket ds) {
        this.ds = ds;
    }

    @Override
    public void run() {
        while (true) {
            byte[] buf = new byte[1024];
            DatagramPacket dp = new DatagramPacket(buf, buf.length);
            // 将数据存入数据包中
            try {
                ds.receive(dp); // 阻塞式方法（没数据，就是等）
            } catch (IOException e) {
                e.printStackTrace();
            }
            String ip = dp.getAddress().getHostAddress();
            String data = new String(dp.getData(), 0, dp.getLength());
            int port = dp.getPort();
            System.out.println("ip: " + ip + "\n"
                    + "data: " + data + "\n"
                    + "port: " + port);
        }
    }
}

public class ChatDemo {

    public static void main(String[] args) throws Exception {
        DatagramSocket send = new DatagramSocket();
        DatagramSocket rece = new DatagramSocket(10002);
        new Thread(new Send(send)).start();
        new Thread(new Rece(rece)).start();
    }

}