Java 和 Arduino 不能使用 RXTX lib 占用同一个 COM 端口？

Question

我正在尝试使用 RXTX 库将字符串从 Arduino Uno 发送到 Java。我的问题是，一旦 Arduino 准备好发送数据，它会占用 Java 应用程序应该读取的 COM 端口吗？其他在线示例有类似的代码，“大概”可以工作 - 通过连接到同一个端口？谢谢。

主要

    public class Main {
        public static void main(String[] args) throws IOException, PortInUseException, NoSuchPortException 
       {
        SerialPortHandler serial = new SerialPortHandler();
        serial.connect("COM10");
        OutputStream serialOut = serial.getSerialOutputStream();
        String s = "hello\r\n";
        serialOut.write(s.getBytes());
        System.out.println(s.toString());
        serialOut.flush();
        serialOut.close();
       }}

RXTX类

public class SerialPortHandler {
private SerialPort serialPort;
private OutputStream outStream;
private InputStream inStream;

public void connect(String portName) throws IOException, PortInUseException, NoSuchPortException {
    try {
        // Obtain a CommPortIdentifier object for the port you want to open
        CommPortIdentifier portId =
                CommPortIdentifier.getPortIdentifier(portName);

        // Get the port's ownership
        serialPort =
                (SerialPort) portId.open("Demo application", 5000);

        // Set the parameters of the connection.
        setSerialPortParameters();

        // Open the input and output streams for the connection. If they won't
        // open, close the port before throwing an exception.
        outStream = serialPort.getOutputStream();
        inStream = serialPort.getInputStream();
    } catch (NoSuchPortException e) {
        System.out.println("no port");
        throw new IOException(e.getMessage());
    } catch (PortInUseException e) {
        System.out.println("port in use");
        throw new IOException(e.getMessage());
    } catch (IOException e) {
        serialPort.close();
        throw e;
    }
}

/**
 * Get the serial port input stream
 * @return The serial port input stream
 */
public InputStream getSerialInputStream() {
    return inStream;
}

/**
 * Get the serial port output stream
 * @return The serial port output stream
 */
public OutputStream getSerialOutputStream() {
    return outStream;
}

/**
 * Sets the serial port parameters
 */
private void setSerialPortParameters() throws IOException {
    int baudRate = 57600;

    try {
        serialPort.setSerialPortParams(
                baudRate,
                SerialPort.DATABITS_8,
                SerialPort.STOPBITS_1,
                SerialPort.PARITY_NONE);

        serialPort.setFlowControlMode(
                SerialPort.FLOWCONTROL_NONE);
    } catch (UnsupportedCommOperationException ex) {
        throw new IOException("Unsupported serial port parameter");
    }
}}

Arduino - 使用软件串行示例 - 在 COM10 上

     #include <SoftwareSerial.h>
     SoftwareSerial mySerial(10, 11); // RX, TX
void setup() {
  // Open serial communications and wait for port to open:
  Serial.begin(57600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }
  Serial.println("Goodnight moon!");
  // set the data rate for the SoftwareSerial port
  mySerial.begin(4800);
  mySerial.println("Hello, world?");
}
void loop() { // run over and over
  if (mySerial.available()) {
    Serial.write(mySerial.read());
  }
  if (Serial.available()) {
    mySerial.write(Serial.read());
  }
}

一旦arduino首先编译，我就会从java中得到错误。 - 看过关于 USB3 端口与 Arduino 混淆的帖子，但在 USB2 上仍然没有运气

        Stable Library
=========================================
Native lib Version = RXTX-2.2pre2
Java lib Version   = RXTX-2.1-7
WARNING:  RXTX Version mismatch
Jar version = RXTX-2.1-7
native lib Version = RXTX-2.2pre2
port in use
Exception in thread "main" java.io.IOException: Unknown Application
at arduinocon.SerialPortHandler.connect(SerialPortHandler.java:38)
at arduinocon.Main.main(Main.java:19)
Error 0x5 at ..\src\termios.c(892): Access is denied.

Answer 1

后来我没有关闭COM连接，所以它占用了端口。我必须手动关闭进程中的 Java.exe 才能释放端口。 - 并编写一个适当的关闭方法;)