Java網(wǎng)絡(luò)編程實例——簡單模擬在線聊天

更新時間：2021年05月31日 11:56:52 作者：bluesky

學(xué)了java網(wǎng)絡(luò)，也是該做個小案例來鞏固一下了。本次案例將使用UDP和多線程模擬即時聊天，簡單練練手。

1、前提知識

需要知道簡單的IO流操作，以及簡單的UDP發(fā)送數(shù)據(jù)包的原理。

需要用到的類：DatagramSocket、DatagramPacket

UDP數(shù)據(jù)包基于DatagramSocket發(fā)送和接收，DatagramPacket用于封裝數(shù)據(jù)包

看下案例：

客戶端發(fā)送消息：

正常情況下從控制臺讀信息，封裝到DatagramPacket之中，再由DatagramSocket的send方法發(fā)出

讀取到bye的時候退出聊天

public class UdpOnlineClient {

    public static void main(String[] args) throws IOException {
        
        DatagramSocket socket = new DatagramSocket(10000);

        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

        while (true) {

            String data = bufferedReader.readLine();
            byte[] datas = data.getBytes();

            DatagramPacket packet = new DatagramPacket(datas, 0, datas.length, new InetSocketAddress("localhost", 9999));

            socket.send(packet);

            if (data.equals("bye")){
                break;
            }

        }
        socket.close();
    }

}

服務(wù)端接收消息：

DatagramSocket的receive方法接收客戶端發(fā)送的消息，打印到控制臺，如果信息是bye則退出聊天

public class UdpOnlineServer {

    public static void main(String[] args) throws IOException {

        DatagramSocket socket = new DatagramSocket(9999);

        while (true){

            byte[] buffer = new byte[1024];

            DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);

            socket.receive(packet);
            String msg = new String(packet.getData(), 0, packet.getLength());

            System.out.println(msg);

            if(msg.equals("bye")){
                break;
            }
        }
        socket.close();

    }

}

試驗：正常開啟客戶端和服務(wù)端后：

客戶端發(fā)送消息：

服務(wù)端接收到信息即成功：

有了這個思路，我們只需要把發(fā)送和接收封裝成發(fā)送類和接收類，使用多線程即可實現(xiàn)聊天了

2、實現(xiàn)思路：

創(chuàng)建UDP發(fā)送實現(xiàn)類TaskSend、UDP接收實現(xiàn)類TaskReceive，以及模擬多線程通信的通信類ChatThread1、ChatThread2

UDP發(fā)送實現(xiàn)類TaskSend：

public class TaskSend implements Runnable{
	
    private String sendIP;
    //自己的服務(wù)端口
    private int ownPort;
    private int sendPort;
    //讀取控制臺輸入流
    private BufferedReader bufferedReader;
    private DatagramSocket socket;

    public TaskSend(String sendIP, int ownPort, int sendPort) {
        this.sendIP = sendIP;
        this.sendPort = sendPort;
        try {
            socket = new DatagramSocket(ownPort);
            bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        } catch (SocketException e) {
            e.printStackTrace();
        } finally {
        }
    }

    //發(fā)送消息
    public void run() {
        while (true) {

            try {
                String data = bufferedReader.readLine();
                //打印自己的消息
                System.out.println("我："+data);
                byte[] datas = data.getBytes();

                DatagramPacket packet = new DatagramPacket(datas, 0, datas.length,new InetSocketAddress(sendIP,sendPort));

                socket.send(packet);
                if (data.equals("bye")) {
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
            }
        }
        socket.close();
    }
}

UDP接收實現(xiàn)類TaskReceive：

public class TaskReceive implements Runnable{

    private int ownPort;
    //發(fā)送信息的人
    private String msgOwner;
    private DatagramSocket socket;

    public TaskReceive(int ownPort, String msgOwner) {
        this.msgOwner = msgOwner;
        try {
            socket = new DatagramSocket(ownPort);
        } catch (SocketException e) {
            e.printStackTrace();
        } finally {
        }
    }
	
    //接收消息
    public void run() {
        while (true) {
            try {
                byte[] buffer = new byte[1024];
                DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);
                socket.receive(packet);
                String msg = new String(packet.getData(), 0, packet.getLength());
                System.out.println(msgOwner+"："+msg);

                if (msg.equals("bye")) {
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
            }
        }
        socket.close();
    }
}

之后使用兩個通信類開啟多線程模擬一下：

模擬老師

public class ChatThread1 {

    public static void main(String[] args) {
        new Thread(new TaskSend("localhost",9999,10000)).start();
        new Thread(new TaskReceive(9998,"老師")).start();
    }

}

模擬學(xué)生

public class ChatThread2 {

    public static void main(String[] args) {

        new Thread(new TaskReceive(9999,"學(xué)生")).start();
        new Thread(new TaskSend("localhost",9998,10001)).start();
    }

}

實例：

學(xué)生