11.监听器：动作事件

    public static void main(String[] args) {
        Frame f = new Frame("MouseListener");
        f.setSize(400, 600);
        f.setLocation(500, 50);
        f.setVisible(true);
        f.setLayout(new FlowLayout());
        f.addWindowListener(new WindowAdapter(){
            @Override
            public void windowClosing(WindowEvent e) {
                System.out.println("windowClosing()");
                System.exit(0);
            }
        });
        Button b1 = new Button("button1");
        Button b2 = new Button("button2");
        f.add(b1);
        f.add(b2);
        /**
         * 使用动作监听器监听鼠标单击按钮事件
         * 创建动作监听器
         */
        ActionListener  myActionListener = new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("actionPerformed:" + e.getActionCommand());
            }
        };
        /**
         * 向按钮添加动作监听器
         */
        b1.addActionListener(myActionListener);
        b2.addActionListener(myActionListener);
    }