Java串行端口运行配置

Question

我想在同一台笔记本电脑上读取和写入串行数据，然后尝试使用此代码。它工作正常，但选择端口是运行配置，如逐个选择COM1和COM2。然而;当我想以相同的方式再次使用端口时，出现NoSuchPortException错误，所以无论如何都要断开端口以进行第二次使用？

package javaSerial;

import java.util.Scanner;

import gnu.io.CommPortIdentifier;  
import gnu.io.SerialPort;

public class RS232 {  

    public void connect(String portName) throws Exception {  
        CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName);  

        if (portIdentifier.isCurrentlyOwned()) {  
            System.out.println("Port in use!");  
        } else {  
            // points who owns the port and connection timeout  
            SerialPort serialPort = (SerialPort) portIdentifier.open("RS232Example", 2000);  

            // setup connection parameters  
            serialPort.setSerialPortParams(  
                38400, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);

            // setup serial port writer  
            CommPortSender.setWriterStream(serialPort.getOutputStream());  

            // setup serial port reader  
            new CommPortReceiver(serialPort.getInputStream()).start(); 
        }  
    }  

    public static void main(String[] args) throws Exception {                   

        String textName;
        int startIndex;
        int byteLength;

        Scanner scan = new Scanner(System.in);
        System.out.println("textName");
        textName = scan.nextLine();
        System.out.println("startIndex");
        startIndex = scan.nextInt();
        System.out.println("byteLength");
        byteLength = scan.nextInt();

        // connects to the port which name (e.g. COM1) is in the first argument
        new RS232().connect(args[0]);

        // send HELO message through serial port using protocol implementation  
        CommPortSender.send(new ProtocolImpl().getMessage(new ReadFileIntoByteArray(textName, startIndex, byteLength).getFileString()));

    }  
}