如何加快serialPort.close（）的时间;目前3秒

Question

在serialPort轮询程序中，我需要每秒钟回复一次。但是，我在日志中注意到serialPort.close();方法需要3秒才能完成。因此我需要等待4秒才能再次轮询端口。有什么想法如何加速港口关闭？为什么会这样？使用RXTXcomm.jar rxtx-2.2pre1。

if (readBufferArray[numBytes-1] == ETXinHex   ){
       one =  one.substring(0,numBytes-1); one =  one + "]"; 
        logger.info("add ]");
        serialPort.close();   //takes 3 seconds !! to close!!
        logger.info("port closed ETX correctly received");
        portFound = false;
        logger.info("port Found false");

    }


  2013-12-21 11:22:20,227 [Thread-16] INFO  - add [
  2013-12-21 11:22:20,227 [Thread-16] INFO  - add ]
  2013-12-21 11:22:23,227 [Thread-16] INFO  - port closed ETX correctly received
  2013-12-21 11:22:23,227 [Thread-16] INFO  - port Found false