readcomm.java

用JAVA语言编写的串口通信程序

import java.awt.*; 
import java.awt.event.*; 
import java.io.*; 
import java.util.*; 
import gnu.io.*;  

class R_Frame extends Frame implements Runnable,ActionListener,SerialPortEventListener
{ 
/* 检测系统中可用的通讯端口类 */
static CommPortIdentifier portId; 
/* Enumeration 为枚举型类,在java.util中 */
static Enumeration portList; 
InputStream inputStream; 
/* 声明RS-232串行端口的成员变量 */
SerialPort serialPort; 
Thread readThread; 
String str=""; 
TextField out_message=new TextField("上面文本框显示接收到的数据"); 
TextArea in_message=new TextArea(); 
Button btnOpen=new Button("打开串口"); 

/*建立窗体*/
R_Frame()
{
super("串口接收数据"); 
setSize(200,200); 
setVisible(true); 
btnOpen.addActionListener(this); 
add(out_message,"South"); 
add(in_message,"Center"); 
add(btnOpen,"North"); 
} //R_Frame() end

/*点击按扭所触发的事件：打开串口,并监听串口. */
public void actionPerformed(ActionEvent event)
{
/*获取系统中所有的通讯端口 */
portList=CommPortIdentifier.getPortIdentifiers(); 
/* 用循环结构找出串口 */
while (portList.hasMoreElements()){ 
/*强制转换为通讯端口类型*/
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("已打开端口COM1 ,正在接收数据..... "); 
}
catch (PortInUseException e) { }

/*设置串口监听器*/
try {
serialPort.addEventListener(this); 
} 
catch (TooManyListenersException e) { }
/* 侦听到串口有数据,触发串口事件*/
serialPort.notifyOnDataAvailable(true); 
} //if end
} //if end
} //while end
readThread = new Thread(this); 
readThread.start(); //线程负责每接收一次数据休眠20秒钟
} //actionPerformed() end

/*接收数据后休眠20秒钟*/
public void run() {
try {
Thread.sleep(20000); 
} 
catch (InterruptedException e) { }
} //run() end

/*串口监听器触发的事件，设置串口通讯参数，读取数据并写到文本区中*/
public void serialEvent(SerialPortEvent event) {
/*设置串口通讯参数：波特率、数据位、停止位、奇偶校验*/
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 {
/* 从线路上读取数据流 */
while (inputStream.available() > 0) { 
int numBytes = inputStream.read(readBuffer); 
} //while end
str=new String(readBuffer); 
/*接收到的数据存放到文本区中*/
in_message.append(str+"\n"); 
}
catch (IOException e) { }
} //serialEvent() end
} //类R_Frame end

public class ReadComm
{
public static void main(String args[])
{
/* 实例化接收串口数据的窗体类 */
R_Frame R_win=new R_Frame(); 
/* 定义窗体适配器的关闭按钮功能 */
R_win.addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{System.exit(0); }
}); 
R_win.pack(); 
}
}