内部类中的构造方法（实现接口）

只需在扩展类的名称后面插入参数即可：

JButton b = new JButton(new AbstractAction("This is a button") {    public void actionPerformed(ActionEvent e) {        System.out.println("button clicked");    }});

另外，您可以使用初始化块：

JButton b = new JButton(new AbstractAction() {    {       // Write initialization pre here (as if it is inside a no-arg constructor)       setLabel("This is a button")    }    public void actionPerformed(ActionEvent e) {        System.out.println("button clicked");    }});