【发布时间】：2014-06-13 06:54:22
【问题描述】：
我已经使用 Device Argox 条形码阅读器编写了读取条形码的程序，Java 中的型号为 As-8250。 我正在使用 javax.com jar 进行串行通信。 这是我编写的从端口号 COM13 读取的程序。
我还将 Argox Utility 的默认端口号设置为 COM13。
package scanhandler;
import java.awt.AWTException;
import java.awt.Robot;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.util.Enumeration;
import java.util.Properties;
import java.util.TooManyListenersException;
import javax.comm.CommPortIdentifier;
import javax.comm.PortInUseException;
import javax.comm.SerialPort;
import javax.comm.SerialPortEvent;
import javax.comm.SerialPortEventListener;
import javax.comm.UnsupportedCommOperationException;
public class ScanHandler implements Runnable, SerialPortEventListener {
private static CommPortIdentifier myCommPortIdentifier;
private static Enumeration portList;
private static String TimeStamp;
private static String driverClass;
private static String connectionString;
private static String comPort;
private Connection myConnection;
private InputStream myInputStream;
private Robot myRobot;
private SerialPort mySerialPort;
private Thread myThread;
public ScanHandler() {
// open serial port
try {
TimeStamp = new java.util.Date().toString();
mySerialPort = (SerialPort) myCommPortIdentifier.open("ComControl", 2000);
//System.out.println(TimeStamp + ": " + myCommPortIdentifier.getName() + " opened for scanner input");
} catch (PortInUseException e) {
e.printStackTrace();
}
// get serial input stream
try {
myInputStream = mySerialPort.getInputStream();
} catch (IOException e) {
e.printStackTrace();
}
// add an event listener on the port
try {
mySerialPort.addEventListener(this);
} catch (TooManyListenersException e) {
e.printStackTrace();
}
mySerialPort.notifyOnDataAvailable(true);
// set up the serial port properties
try {
mySerialPort.setSerialPortParams(9600,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
mySerialPort.setDTR(false);
mySerialPort.setRTS(false);
} catch (UnsupportedCommOperationException e) {
e.printStackTrace();
}
// make a robot to pass keyboard data
try {
myRobot = new Robot();
} catch (AWTException e) {
e.printStackTrace();
}
// create the thread
myThread = new Thread(this);
myThread.start();
}
public void run() {
try {
Thread.sleep(100);
} catch (InterruptedException e) {}
}
// on scan
public void serialEvent(SerialPortEvent event) {
if (event.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
StringBuilder myStringBuilder = new StringBuilder();
int c;
try {
// append the scanned data onto a string builder
while ((c = myInputStream.read()) != 10){
if (c != 13) myStringBuilder.append((char) c);
}
// send to keyboard buffer if it the barcode doesn't start with '5'
if (myStringBuilder.charAt(0) != '5') {
for (int i = 0; i < myStringBuilder.length(); i++) {
myRobot.keyPress((int) myStringBuilder.charAt(i));
myRobot.keyRelease((int) myStringBuilder.charAt(i));
}
// here's the scanned barcode as a variable!
} else {
TimeStamp = new java.util.Date().toString();
System.out.println(TimeStamp + ": scanned input received:" + myStringBuilder.toString());
}
// close the input stream
myInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
// read ScanHandler properties
Properties myProperties = new Properties();
// myProperties.load(new FileInputStream("config.properties"));
comPort = "COM13";
try {
// get our pre-defined COM port
myCommPortIdentifier = CommPortIdentifier.getPortIdentifier(comPort);
ScanHandler reader = new ScanHandler();
} catch (Exception e) {
TimeStamp = new java.util.Date().toString();
System.out.println(TimeStamp + ": " + comPort + " " + myCommPortIdentifier);
System.out.println(TimeStamp + ": msg1 - " + e);
}
};
}
->此程序正在侦听端口 COM13。并打印输入流中的字符串（由条形码阅读器扫描）。
->===========================问题在这里================ ======= 当我先插入 USB 并通过设备实用程序强制它使用端口 COM13 时。它工作得很好。 之后，当我运行我的 Java 程序以侦听同一端口时，它会抛出异常
javax.comm.PortInUseException: Port currently owned by Unknown Windows Application
at javax.comm.CommPortIdentifier.open(CommPortIdentifier.java:337)
at scanhandler.ScanHandler.<init>(ScanHandler.java:41)
at scanhandler.ScanHandler.main(ScanHandler.java:141)
Fri Jun 13 12:20:05 IST 2014: COM13 javax.comm.CommPortIdentifier@d1a2f1
Fri Jun 13 12:20:05 IST 2014: msg1 - java.lang.NullPointerException
那么，如果我的 proram 被拒绝在该端口上侦听，我怎么能读取扫描的条形码。
任何帮助将不胜感激。
【问题讨论】：
-
您需要找出哪个进程已经打开了该串口并结束它，以便您的程序可以打开该端口。
标签： serial-port barcode barcode-scanner