一段时间后，jssc writebytes在Linux上停止工作

Question

I'm programming in Java to talk with a device connected to a com-port (connected to the PC through USB, but by an RS232 to USB cable in between). I've written a program that talks with jssc and that functioned correctly under Windows, it kept working for a longer time even when nothing happens, like it should. Under Linux the program stops responding after a minute of 2 or 3 and I wonder why.

The run statement is as follows

public void run() {
    while (stayConnected) {
        try {
            serialPort.writeBytes(pollBuf);
            readResponse(false);
            Thread.sleep(400);
            serialPort.writeBytes(readEvents);
            readResponse(true);
        } catch (InterruptedException ie) {
            logger.error("Interrupted exception: " + ie.getMessage());
        } catch (SerialPortException spe) {
            logger.error("SerialPortException: " + spe.getMessage());
        }
    }
}

To know where the program hangs I've added loglines and I found out that the last command to function correctly is the last call to readResponse(true) and the first to stop returning is serialPort.writeBytes(pollBuf). Hoping that it would solve the issue I split the 400 ms sleep in two and placed the other sleep before serialPort.writeBytes(pollBuf). That doesn't help. Somehow the serialPort.writeBytes function just never returns and doesn't throw an exception either.

Does anyone have a guess of what the failure might be? It's not the stayConnected boolean as I never call the function yet that sets it so false;

edit: I've just added a counter and the program gets into the loop 283 and 285 times when I run it twice, that's pretty close and both around 2 minutes ...

Answer 1

I'm having a very similar problem under Windows 7. I've deployed my software to a clients PC and after about 5 to 6 hours the serial port can be opened but not able to be written to.

As per the example my code is similar:

String readPort(String command, int byteToRead) {

    String Input = null;
    if (opened == true) {
        try {
            serialPort.writeString(command);

            Input = serialPort.readString(byteToRead);

        } catch (SerialPortException ex) {
            System.out.println(ex);
        }
    }

    return Input;
}

The line of code that does not return is

serialPort.writeString(command);

Answer 2

我有完全相同的问题，原因是另一个线程关闭了端口，而主要线程仍在读取，我看到您的代码段是关于Runnable的，因此请仔细检查您的多线程管理。