问KeyBindings在JApplet中无法正常工作

EN

package Game;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class GameTest extends JApplet{
    private PAPITest papi;
    private TestPane panel;
    private boolean inMenu = true;
    private ImageIcon ii;
    private Image image;

    public void init(){
        setFocusable(true);
        requestFocusInWindow();
        requestFocus();
        ii = new ImageIcon("Ball Jump.png");
        image = ii.getImage();
        papi = new PAPITest();
        panel = new TestPane();
        add(panel);
        setSize(600,600);
        setVisible(true);
    }

    public void paint(Graphics g){
        if(inMenu == true){
            Graphics2D g2D = (Graphics2D) g;
            g2D.drawImage(image, 0, 0, this);
            repaint();
        }
    }

    public class TestPane extends JPanel {

        public TestPane() {
            InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
            ActionMap am = getActionMap();

            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0, false), "pressed");
            im.put(KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0, true), "released");

            am.put("pressed", new AbstractAction() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    if(inMenu == true){
                        inMenu = false;
                        remove(panel);
                        papi.setSize(600,600);
                        papi.setAlive(true);
                        add(papi);            
                        setVisible(true); 
                    }

                    if (papi.isAlive() != true){ 
                        remove(papi);
                        papi = new PAPITest();
                        papi.setSize(600,600);
                        add(papi);
                        setVisible(true);
                        repaint();    
                    } 
                }
            });

            am.put("released", new AbstractAction() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    if(inMenu == true){
                        inMenu = false;
                        remove(panel);
                        papi.setSize(600,600);
                        papi.setAlive(true);
                        add(papi);            
                        setVisible(true); 
                    }

                    if (papi.isAlive() != true){ 
                        remove(papi);
                        papi = new PAPITest();
                        papi.setSize(600,600);
                        add(papi);
                        setVisible(true);
                        repaint();    
                    }
                }
            });

            setFocusable(true);
            requestFocusInWindow();        
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(600, 600);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2D = (Graphics2D) g;
            g2D.drawImage(image, 0, 0, this);
            repaint();
        }
    }
}