应用程序不通过串口发送任何内容

Question

我使用GUI构建了以下应用程序，基于RXTX网站的示例。唯一的问题是它实际上并没有向串行设备发送任何东西。我没有包含任何与Swing GUI相关的自动生成的代码。

import gnu.io.*;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.logging.Level;
import java.util.logging.Logger;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author Daniel
 */
public class ComForm extends javax.swing.JFrame {

    /**
     * Creates new form ComForm
     */
    public ComForm() {
        super();
        initComponents();
    }

    void connect ( String portName ) throws Exception
    {
        CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName);
        if ( portIdentifier.isCurrentlyOwned() )
        {
            System.out.println("Belea: Portu-i folosit!");
        }
        else
        {
            CommPort commPort = portIdentifier.open(this.getClass().getName(),2000);

            if ( commPort instanceof SerialPort )
            {
                SerialPort serialPort = (SerialPort) commPort;
                serialPort.setSerialPortParams(9600,SerialPort.DATABITS_8,SerialPort.STOPBITS_1,SerialPort.PARITY_NONE);

                inputStream = serialPort.getInputStream();
                outputStream = serialPort.getOutputStream();
                open = true;
            }
            else
            {
                System.out.println("Belea: Numa porturi seriale!");
            }
        }     
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")

    private void sendButtonActionPerformed(java.awt.event.ActionEvent evt) {
        String c = this.sendField.getText();

        if (open == true) {
            try {
                System.out.println(c);
                outputStream.write(c.getBytes()); //write to serial port
            } catch ( Exception e ) {
                e.printStackTrace();
            }
        }

    }

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        if(open == false)
        {
            try {
                connect("COM3");
            }
            catch ( Exception e ) {
                e.printStackTrace();
            }
            if(open == true)
            {
                this.jLabel3.setText("CONECTAT!");
                this.jButton1.setEnabled(false);
                this.sendButton.setEnabled(true);
                this.sendField.setText("");
            }
        }
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /*
         * Set the Nimbus look and feel
         */

        /*
         * Create and display the form
         */
        java.awt.EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new ComForm().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JButton jButton1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JButton sendButton;
    private javax.swing.JTextField sendField;
    // End of variables declaration
    private String portName;
    private CommPort commPort;
    private SerialPort serialPort;
    private CommPortIdentifier portIdentifier = null;
    private InputStream inputStream;
    private OutputStream outputStream;
    private boolean open=false;

}