import java.awt.Color;import java.awt.event.*;import javax.swing.*;public class My implements ActionListener{    JFrame f;    JButton b;    JPanel p;   public  My(){    f=new JFrame();     p=new JPanel();    b=new JButton("点击");    b.addActionListener(this);    f.add(p);    p.add(b);    f.setSize(400,300);    f.setVisible(true);}  public static void main(String[]args){    new My();    }@Overridepublic void actionPerformed(ActionEvent e) {    p.setBackground(Color.pink);                   }          }