16:20:48,234 ERROR [STDERR] Exception in thread "AWT-EventQueue-0"
java.lang.NullPointerException
16:20:48,234 ERROR [STDERR] at com.port.action.R_Frame.actionPerformed(R_Frame.java:77)
16:20:48,234 ERROR [STDERR] at java.awt.Button.processActionEvent(Button.java:392)
16:20:48,234 ERROR [STDERR] at java.awt.Button.processEvent(Button.java:360)
16:20:48,234 ERROR [STDERR] at java.awt.Component.dispatchEventImpl(Component.java:4630)
16:20:48,234 ERROR [STDERR] at java.awt.Component.dispatchEvent(Component.java:4460)
16:20:48,234 ERROR [STDERR] at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
我做的一个JAVA读取据串口数据,第一次打开可以,第2次打开就报这个错````只有重新启动TOMCAT才可以````高手看看``
我的action是这样
/**//* 实例化接收串口数据的窗体类 */
final R_Frame R_win=new R_Frame();
R_win.setPortName(portName);
R_win.setRate(rate);
R_win.setDATABITS(DATABITS);
R_win.setSTOPBITS(STOPBITS);
/**//* 定义窗体适配器的关闭按钮功能 */
R_win.addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{ R_win.dispose();
return;
}
});
R_win.pack();
return null;
java.lang.NullPointerException
16:20:48,234 ERROR [STDERR] at com.port.action.R_Frame.actionPerformed(R_Frame.java:77)
16:20:48,234 ERROR [STDERR] at java.awt.Button.processActionEvent(Button.java:392)
16:20:48,234 ERROR [STDERR] at java.awt.Button.processEvent(Button.java:360)
16:20:48,234 ERROR [STDERR] at java.awt.Component.dispatchEventImpl(Component.java:4630)
16:20:48,234 ERROR [STDERR] at java.awt.Component.dispatchEvent(Component.java:4460)
16:20:48,234 ERROR [STDERR] at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
16:20:48,250 ERROR [STDERR] at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
我做的一个JAVA读取据串口数据,第一次打开可以,第2次打开就报这个错````只有重新启动TOMCAT才可以````高手看看``
我的action是这样
/**//* 实例化接收串口数据的窗体类 */
final R_Frame R_win=new R_Frame();
R_win.setPortName(portName);
R_win.setRate(rate);
R_win.setDATABITS(DATABITS);
R_win.setSTOPBITS(STOPBITS);
/**//* 定义窗体适配器的关闭按钮功能 */
R_win.addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{ R_win.dispose();
return;
}
});
R_win.pack();
return null;
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GUI我没有怎么用过,但是看API觉得这里你用System.exit(-1);会达到你要的效果
try {
serialPort.addEventListener(this);
}
catch (TooManyListenersException e) { }
/**//* 侦听到串口有数据,触发串口事件*/
serialPort.notifyOnDataAvailable(true);
readThread = new Thread(this);
readThread.start();//线程负责每接收一次数据休眠20秒钟
} //actionPerformed() end
你都知道哪行 这行里有什么对象
你打印一下不就行了?
serialPort == null