public class UdpClient {
    public static void main(String[] args) throws IOException {
        //建立一個socket
        DatagramSocket socket = new DatagramSocket();
        //創(chuàng)建一個數(shù)據(jù)包
        String msg = "你好啊，服務(wù)器~";
        InetAddress localhost = InetAddress.getByName("localhost");
        int port = 9090;
        DatagramPacket packet = new DatagramPacket(msg.getBytes(), 0, msg.getBytes().length, localhost, port);
        //發(fā)送數(shù)據(jù)包
        socket.send(packet);
        //關(guān)閉流
        socket.close();
    }
}

public class UdpServer {
    public static void main(String[] args) throws IOException {
        //開啟端口
        DatagramSocket socket = new DatagramSocket(9090);
        //接收數(shù)據(jù)包
        byte[] bytes = new byte[1024];
        DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length);
        //阻塞接收
        socket.receive(packet);
        String msg = new String(packet.getData(),0,packet.getLength());
        System.out.println("接收到客戶端發(fā)來的數(shù)據(jù)：" + msg);
        //關(guān)閉數(shù)據(jù)流
        socket.close();
    }
}

//客戶端
public class TalkSend implements Runnable {
    DatagramSocket socket = null;
    BufferedReader br = null;
    private int formPort;
    private String toIp;
    private int toPort;
    public TalkSend(int formPort, String toIp, int toPort) {
        this.formPort = formPort;
        this.toIp = toIp;
        this.toPort = toPort;
        try {
            socket = new DatagramSocket(this.formPort);
            //準(zhǔn)備數(shù)據(jù) 控制臺讀取System.in
            br = new BufferedReader(new InputStreamReader(System.in));
        } catch (SocketException e) {
            e.printStackTrace();
        }
    }
    @Override
    public void run() {
        while (true) {
            try {
                String msg = br.readLine();
                byte[] bytes = msg.getBytes();
                DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length, new InetSocketAddress(this.toIp, this.toPort));
                //發(fā)送數(shù)據(jù)
                socket.send(packet);
                if (msg.equals("bye")) {
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        socket.close();
    }
}

//服務(wù)端
public class TalkReceive implements Runnable {
    DatagramSocket socket = null;
    private int port;
    private String msgForm;
    public TalkReceive(int port, String msgForm) {
        this.port = port;
        this.msgForm = msgForm;
        try {
            socket = new DatagramSocket(port);
        } catch (SocketException e) {
            e.printStackTrace();
        }
    }
    @Override
    public void run() {
        while (true) {
            try {
                //準(zhǔn)備接收包裹
                byte[] bytes = new byte[1024];
                DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length);
                socket.receive(packet);
                //斷開連接 bye
                String msg = new String(packet.getData(), 0, packet.getLength());
                System.out.println(msgForm + ":" + msg);
                if ("bye".equals(msg)) {
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        socket.close();
    }
}

public class TalkStudent {
    public static void main(String[] args) {
        new Thread(new TalkSend(7777,"localhost",8888)).start();
        new Thread(new TalkReceive(9999,"老師")).start();
    }
}

public class TalkTeacher {
    public static void main(String[] args) {
        new Thread(new TalkSend(5555,"localhost",9999)).start();
        new Thread(new TalkReceive(8888,"學(xué)生")).start();
    }
}