javascript - 为什么这个 Node.js tcp 服务器在关闭之前不会写回 Java 客户端？

Question

Here是我发现的用node.js编写的tcp服务器的示例:

net.createServer(function(sock) {

    // We have a connection - a socket object is assigned to the connection automatically
    console.log('CONNECTED: ' + sock.remoteAddress +':'+ sock.remotePort);

    // Add a 'data' event handler to this instance of socket
    sock.on('data', function(data) {

        console.log('DATA ' + sock.remoteAddress + ': ' + data);
        // Write the data back to the socket, the client will receive it as data from the server
        sock.write('You said "' + data + '"');

    });

    // Add a 'close' event handler to this instance of socket
    sock.on('close', function(data) {
        console.log('CLOSED: ' + sock.remoteAddress +' '+ sock.remotePort);
    });

}).listen(PORT, HOST);

console.log('Server listening on ' + HOST +':'+ PORT);

我试图使用它作为 tcp 服务器的基础，该服务器必须同时处理多个传入连接。这是我编写的一个 Java 程序来测试这一点:

public static final String MESSAGE = "Hellow world";
    public static Semaphore networkLock;

    public static void main(String[] args) 
    {
        //writeMessage(MESSAGE);

        Thread[] threadPool = new Thread[10];
        networkLock = new Semaphore(1);

        for (int i = 0; i < threadPool.length; i++) 
        {
            threadPool[i] = new Thread(new Runnable() {

                @Override
                public void run() {
                    writeMessage(MESSAGE);

                }
            });

            threadPool[i].start();
        }

    }

    public static void writeMessage(String test)
    {
        try {
            if(sock == null || sock.isClosed())
                sock = new Socket(HOST, PORT);

            DataOutputStream out =
                    new DataOutputStream(sock.getOutputStream());
            System.out.println("Writting message");

            //networkLock.acquire();
            out.writeUTF(test);
            //networkLock.release();

              BufferedReader in = new BufferedReader(
                        new InputStreamReader(sock.getInputStream()));

              System.out.println("Waiting for reply");
              String input = in.readLine();

              System.out.println(input);
//            in.close();
//          out.close();
//          sock.close();

        } catch (UnknownHostException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
    }

当我启动客户端时，我从客户端得到的唯一输出是多次“正在写入消息”和“正在等待回复”。当我关闭服务器时，我终于得到了 You said“Hello world” 的响应，并且通常会抛出一个或两个 null 。至于服务器，它打印出两条打印语句就很好了。你认为有人可以帮助我吗？

Answer 1

Java 客户端使用 in.readLine() 在输入流中查找换行符。但是，服务器不会向客户端套接字写入换行符。

所以改变这个:

sock.write('You said "' + data + '"');

对此:

sock.write('You said "' + data + '"\n');