apache-spark - 为什么流无法连接到Java套接字客户端？

Question

我正在研究Spark流处理以处理实时数据，并且构建了示例SparkCount的wordCount，然后可以运行以下示例:

/bin/run-example org.apache.spark.streaming.examples.JavaNetworkWordCount local[2] localhost 9999

而且，如果我在另一个终端中运行 nc -L -p 9999，那么我可以在该终端中键入字母，并且该示例可以接收字母并给出正确的结果。

但是我开发了一个Java套接字客户端来将内容发送到9999端口-该示例为什么不能接收它？我认为该示例仅监视9999端口，并从该端口接收任何内容。

这是Java代码:

    File file = new File("D:\\OutputJson.dat");
    long l = file.length();
    socket = new Socket();
    boolean connected = false;
    while (!connected) {
        //not stop until send successful
        try {
            socket.connect(new InetSocketAddress("localhost", 9999));
            connected = true;
            System.out.println("connected success!");
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("connected failed!");
            Thread.sleep(5000);
        }
    }
    dos = new DataOutputStream(socket.getOutputStream());
    fis = new FileInputStream(file);
    sendBytes = new byte[1024];
    while ((length = fis.read(sendBytes, 0, sendBytes.length)) > 0) {
        sumL += length;
        System.out.println("sent:" + ((sumL / l) * 100) + "%");
        dos.write(sendBytes, 0, length);
        dos.flush();
    }
    if (sumL == l) {
        bool = true;
    }

此Java函数始终返回以下错误:

java.net.SocketException: Socket closed

我已经开发了另一个Java类来接收来自此发送套接字的数据，并且它可以正常工作，为什么不能通过此套接字触发接收？

Answer 1

从内存来看，我认为我使用了ServerSocket。该代码是这样的:

public void sendMsg(String msg) throws IOException {
    ServerSocket serverSocket = null;
    Socket clientSocket = null;
    try {
        serverSocket = new ServerSocket(port);
        clientSocket = serverSocket.accept();
        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
        out.write(msg);
        out.flush();
        out.close();
    } finally {
        try {
            clientSocket.close();
            serverSocket.close();
        } finally {
            clientSocket = null;
            serverSocket = null;
        }
    }
}