JAVA RXTX串口无法找到指定蓝牙串口

Question

程序就是一个很简单的写数据，在枚举已有串口时，能找到其他的COM端口，无法发现蓝牙串口COM9
但是使用串口调试助手连接COM9发送数据都正常，
求高手指点
代码如下

 import java.io.*;
import java.util.*;

import gnu.io.CommPortIdentifier;
import gnu.io.PortInUseException;
import gnu.io.SerialPort;
import gnu.io.UnsupportedCommOperationException;

public class SimpleWrite {
static Enumeration portList;
static CommPortIdentifier portId;
static String messageString = "A1";
static SerialPort serialPort;
static OutputStream outputStream;

public static void main(String[] args) {
    portList = CommPortIdentifier.getPortIdentifiers();

    while (portList.hasMoreElements()) {
        portId = (CommPortIdentifier) portList.nextElement();
        if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
             if (portId.getName().equals("COM9")) {
                 System.out.println("找到");
                try {
                    serialPort = (SerialPort)
                        portId.open("SimpleWriteApp", 2000);
                } catch (PortInUseException e) {}
                try {
                    outputStream = serialPort.getOutputStream();
                } catch (IOException e) {}
                try {
                    serialPort.setSerialPortParams(9600,
                        SerialPort.DATABITS_8,
                        SerialPort.STOPBITS_1,
                        SerialPort.PARITY_NONE);
                } catch (UnsupportedCommOperationException e) {}
                try {
                    outputStream.write(messageString.getBytes());
                } catch (IOException e) {}
            }
        }
    }
}
}