/******************************************
*　程序文件名稱：ReadComm.java
*  功能：從串行口COM1中接收數(shù)據(jù)
******************************************/
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.comm.*;

 class R_Frame extends Frame implements Runnable,ActionListener,SerialPortEventListener
{ 
	 /*  檢測系統(tǒng)中可用的通訊端口類 */
   static CommPortIdentifier     portId; 
     /*  Enumeration 為枚舉型類,在java.util中  */
   static Enumeration            portList; 
   InputStream                   inputStream;
     /*  聲明RS-232串行端口的成員變量  */
   SerialPort     serialPort;    
   Thread         readThread;
   String         str="";
   TextField      out_message=new TextField("上面文本框顯示接收到的數(shù)據(jù)");
   TextArea       in_message=new TextArea(); 
   Button         btnOpen=new Button("打開串口");

 /*建立窗體*/
 R_Frame()
 {
 super("串口接收數(shù)據(jù)");
   setSize(200,200);
   setVisible(true);
   btnOpen.addActionListener(this);
   add(out_message,"South");
   add(in_message,"Center");
   add(btnOpen,"North");
 } //R_Frame() end

 /*點(diǎn)擊按扭所觸發(fā)的事件：打開串口,并監(jiān)聽串口. */
 public void actionPerformed(ActionEvent event)
 {
  /*獲取系統(tǒng)中所有的通訊端口  */
  portList=CommPortIdentifier.getPortIdentifiers();
  /* 用循環(huán)結(jié)構(gòu)找出串口 */
  while (portList.hasMoreElements()){  
   /*強(qiáng)制轉(zhuǎn)換為通訊端口類型*/
    portId=(CommPortIdentifier)portList.nextElement();
    if(portId.getPortType() == CommPortIdentifier.PORT_SERIAL){
      if (portId.getName().equals("COM1")) {
        try {
serialPort = (SerialPort) portId.open("ReadComm", 2000);
	      out_message.setText("已打開端口COM1 ,正在接收數(shù)據(jù)..... ");
	     }
  catch (PortInUseException e) { }

	    /*設(shè)置串口監(jiān)聽器*/
	    try {
serialPort.addEventListener(this);
} 
        catch (TooManyListenersException e) { }
        /* 偵聽到串口有數(shù)據(jù),觸發(fā)串口事件*/
	    serialPort.notifyOnDataAvailable(true);
      } //if end
     } //if end
   } //while end
   readThread = new Thread(this);
   readThread.start();//線程負(fù)責(zé)每接收一次數(shù)據(jù)休眠20秒鐘
 } //actionPerformed() end
 
  /*接收數(shù)據(jù)后休眠20秒鐘*/
   public void run() {
        try {
Thread.sleep(20000); 
} 
        catch (InterruptedException e) {  }
   }  //run() end

      /*串口監(jiān)聽器觸發(fā)的事件，設(shè)置串口通訊參數(shù)，讀取數(shù)據(jù)并寫到文本區(qū)中*/
   public void serialEvent(SerialPortEvent event) {
	  /*設(shè)置串口通訊參數(shù)：波特率、數(shù)據(jù)位、停止位、奇偶校驗(yàn)*/
      try {
           serialPort.setSerialPortParams(9600,
                　　SerialPort.DATABITS_8,
                　　SerialPort.STOPBITS_1,
                　　SerialPort.PARITY_NONE);
}
 catch (UnsupportedCommOperationException e) {　　　}
	 byte[] readBuffer = new byte[20];
     try {
inputStream = serialPort.getInputStream();
}
        catch (IOException e) {}
try {
　　　/* 從線路上讀取數(shù)據(jù)流 */
         while (inputStream.available() > 0) { 
               int numBytes = inputStream.read(readBuffer);
             }    //while end
		 str=new String(readBuffer);
         /*接收到的數(shù)據(jù)存放到文本區(qū)中*/
		 in_message.append(str+"\n");
	 }
 catch (IOException e) {    }
   } //serialEvent() end
}  //類R_Frame end

public class ReadComm
{
public static void main(String args[])
  {
    /*  實(shí)例化接收串口數(shù)據(jù)的窗體類  */
 R_Frame R_win=new R_Frame();
/*  定義窗體適配器的關(guān)閉按鈕功能 */
     R_win.addWindowListener(new WindowAdapter()
             {public void windowClosing(WindowEvent e)
                {System.exit(0); }
      });
   R_win.pack();
 }
}