用ActionMap/InputMap添加JPanel上的键盘事件问题

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;



public class SplashScreen2 extends JWindow {

	private int duration;

	

	public SplashScreen2() {

	}

	

	public void showSplash() {

		JPanel content = (JPanel)getContentPane();

		content.setBackground(Color.white);

		

		//close the window when dragging

		content.addMouseMotionListener(new MouseAdapter(){

				public void mouseDragged(MouseEvent e){

					System.out.println(e);

					System.exit(0);

				}				

			});

		//show the clicked info	

		content.addMouseListener(new MouseAdapter(){

				public void mouseClicked(MouseEvent e){

					System.out.println(e);

				}				

			});

			

		//show the key event info	

		KeyStroke theEnter = KeyStroke.getKeyStroke(KeyEvent.VK_ENTER,java.awt.event.InputEvent.SHIFT_DOWN_MASK,false);		

		ActionMap contentActionMap = content.getActionMap();

		InputMap  contentInputMap  = content.getInputMap();		

		contentInputMap.put(theEnter,"Kind_of_Input");

		contentActionMap.put("Kind_of_Input",new AbstractAction(){

			public void actionPerformed(ActionEvent e){

				System.out.println(e);

			}

		});





		setBounds(500,500,400,200);

		setVisible(true);		

	}

	

	public static void main(String[] args) {

		SplashScreen2 splash = new SplashScreen2();

		splash.showSplash( );

	}

}