pw1txt.addFocusListener(new FocusListener()
         {
          public void focusGained(FocusEvent e)
          {
          pwlad.setText("密码在16个个字符之内!");
          }
          public void focusLost(FocusEvent e)
          {
                       pwlab.setText("");
          }
         }
          );应该是这样调用....除了这个之外还需要什么?  焦点管理器?