写 - 读 - 写到串行端口

Question

我正在尝试使用我的PC的SERIAL COM PORT进行与微控制器通信的应用程序。

在我的程序中，我首先向微控制器发送一个字符串（＆＃34; Connect1＆＃34;）并等待Ack响应（＆＃34; Ack1_PIC＆＃34;）。

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         


    SimpleRead reader = new SimpleRead();

    // Get list of COM ports
    portList = gnu.io.CommPortIdentifier.getPortIdentifiers();
    while (portList.hasMoreElements())
    {
        portId = (gnu.io.CommPortIdentifier) portList.nextElement();
        if (portId.getPortType() == gnu.io.CommPortIdentifier.PORT_SERIAL) {
             if (portId.getName().equals("COM1")) {
                openPort();
                write("Connect1"); // -> 1st Write operation
            }
        }

        System.out.println("\nWrite1");
    }
    serialPort.close();

    // Get list of COM ports
    portList = gnu.io.CommPortIdentifier.getPortIdentifiers();
    while (portList.hasMoreElements()) {
        portId = (gnu.io.CommPortIdentifier) portList.nextElement();
        if (portId.getPortType() == gnu.io.CommPortIdentifier.PORT_SERIAL) {
             if (portId.getName().equals("COM1")) {
                System.out.println("Read1");
                reader = new SimpleRead(portId,portList,serialPort,readThread,115200,SerialPort.DATABITS_8,SerialPort.STOPBITS_1,SerialPort.PARITY_NONE); // / -> 1st Read operation
            }
        }
        // Waiting for the desired String
        while(!strCompare(reader.readBuffer,"Ack1_PIC"));
        System.out.println(new String(reader.readBuffer));
    }
    serialPort.close();        

到目前为止一切正常。

然后我尝试向微控制器发送另一个字符串（＆＃34; Connect2＆＃34;），但微控制器没有收到它，我不知道原因：

    portList = gnu.io.CommPortIdentifier.getPortIdentifiers();
    while (portList.hasMoreElements()) {
        portId = (gnu.io.CommPortIdentifier) portList.nextElement();
        if (portId.getPortType() == gnu.io.CommPortIdentifier.PORT_SERIAL) {
             if (portId.getName().equals("COM1")) {
                write("Connect2"); // -> 2nd Write operation
            }   
        }
        System.out.println("Write2");
    }
    // close port
    serialPort.close();

写方法：

public void write (String messageString)
{        
 try {
     outputStream = serialPort.getOutputStream();
 } catch (IOException e) {}

 try {
  //  System.out.println("Setting parameters");
     serialPort.setSerialPortParams(115200,
     SerialPort.DATABITS_8,
     SerialPort.STOPBITS_1,
     SerialPort.PARITY_NONE);
     serialPort.setFlowControlMode(SerialPort.FLOWCONTROL_NONE);
 } catch (UnsupportedCommOperationException e) {}
 //System.out.println("Ok");
 try {
   //  System.out.println("Writing to serial port");
     outputStream.write(messageString.getBytes());
     //outputStream.close();
 } catch (IOException e) {}
}

和简单阅读课程：

public class SimpleRead implements Runnable, SerialPortEventListener
{
public InputStream inputStream;
public int size = 50;
public int numBytes = 0;
public byte readBuffer [] = new byte [size];

public SimpleRead()
{
}

public SimpleRead(CommPortIdentifier portId, Enumeration portList, SerialPort serialPort, Thread readThread,int baud,int databits,int stopbits,int parity) {
    // Open Port
    try {
        serialPort = (SerialPort) portId.open("SimpleReadApp", 2000);
    } catch (PortInUseException e) {System.out.println(e);}

    // open stream
    try {
        inputStream = serialPort.getInputStream();
    } catch (IOException e) {System.out.println(e);}

    // add event listeners
    try {
        serialPort.addEventListener(this);
} catch (TooManyListenersException e) {System.out.println(e);}
    serialPort.notifyOnDataAvailable(true);

    // set serial parameters
    try {
        serialPort.setSerialPortParams(baud,databits,stopbits,parity);
        serialPort.setFlowControlMode(SerialPort.FLOWCONTROL_NONE);
    } catch (UnsupportedCommOperationException e) {System.out.println(e);}
    readThread = new Thread(this);
    readThread.start();
}

public void run() {
    try {
        Thread.sleep(20000);
    } catch (InterruptedException e) {System.out.println(e);}
}

// event listener method
public void serialEvent(SerialPortEvent event) {

    for(int i = 0; i < size;i++)
        readBuffer[i] = 0;    
    switch(event.getEventType()) {
    case SerialPortEvent.BI:
    case SerialPortEvent.OE:
    case SerialPortEvent.FE:
    case SerialPortEvent.PE:
    case SerialPortEvent.CD:
    case SerialPortEvent.CTS:
    case SerialPortEvent.DSR:
    case SerialPortEvent.RI:
    case SerialPortEvent.OUTPUT_BUFFER_EMPTY:
        break;
    case SerialPortEvent.DATA_AVAILABLE:
        try {
            numBytes = 0;
            while (inputStream.available() > 0) {
                // Copy from serial to byte array "readBuffer"
                numBytes = inputStream.read(readBuffer);
            }
            // Close InputStream
            //inputStream.close();
             //System.out.println(new String(readBuffer));

        } catch (IOException e) {System.out.println(e);}
        break;
    }
  }
}

我意识到的另一件事是，如果我连续2次写入，我会正确接收两个字符串。

有什么建议吗？