public focustest() {//构造方法  
    ...............  
    Toolkit tk = Toolkit.getDefaultToolkit();  
     tk.addAWTEventListener(new GlobalEventListener(),AWTEvent.KEY_EVENT_MASK);  
}  
   
 class GlobalEventListener implements AWTEventListener {//子类  
     public void eventDispatched(AWTEvent evt) {  
         if (evt instanceof KeyEvent) {  
             KeyEvent kevt = (KeyEvent) evt;  
             if (kevt.getID() == KeyEvent.KEY_PRESSED) {  
                 String modifier = KeyEvent.getKeyModifiersText(kevt.getModifiers());  
                 String key = KeyEvent.getKeyText(kevt.getKeyCode());  
                 System.out.println("Modifier:"+modifier+"|Key:"+key);  
             }  
         }  
     }  
}