Swing 添加Esc快捷键退出程序

JFrame demo = new JFrame();
demo.addKeyListener(
    new KeyListener(){
            public void keyReleased(KeyEvent e) {
                 if (e.getKeyCode() == KeyEvent.VK_ESCAPE ) {  
                                UIHelper.closeWindow(demo);
 8                   }                    
            }
            public void keyTyped(KeyEvent e) {
            }
            public void keyPressed(KeyEvent e) {
            }
});