N年不用java写图形界面，但想了想，在点击事件中给上边图形重绘的方法重新来一遍应该可行。代码如下：

package com.yimik.test.swing;

import java.awt.Graphics;

import java.awt.Image;

import java.awt.event.MouseAdapter;

import java.awt.event.MouseEvent;

import javax.swing.ImageIcon;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

public class BackgroundTest extends JFrame{

private static final long serialVersionUID = 1L;

private JButton b;

private JPanel p ;

public BackgroundTest() {

p = new MyPanel();

p.setBounds(0, 0, 500,200);

this.setDefaultCloseOperation(EXIT_ON_CLOSE);

this.setSize(500, 500);

this.setVisible(true);

this.setLayout(null);

this.add(p);

b = new JButton("点击换背景");

b.setBounds(0, 300, 100, 30);

this.add(b);

b.addMouseListener(new MouseAdapter() {

@Override

public void mouseClicked(MouseEvent e) {

super.mouseClicked(e);

ImageIcon image=new ImageIcon(getClass().getResource("/imgs/img2.jpg"));

image.setImage(image.getImage().getScaledInstance(p.getWidth(),p.getHeight(),Image.SCALE_FAST));

image.paintIcon(p, p.getGraphics(),0, 0);

}

});

}

public static void main(String[] args) {

new BackgroundTest();

}

}

class MyPanel extends JPanel{

private static final long serialVersionUID = 1L;

@Override

protected void paintComponent(Graphics g){//重写paintComponent方法以实现jPanel加背景

super.paintComponent(g);

ImageIcon image=new ImageIcon(getClass().getResource("/imgs/img1.jpg")); //获取图像

image.setImage(image.getImage().getScaledInstance(this.getWidth(),this.getHeight(),Image.SCALE_FAST)); //调整图像的分辨率以适应容器

image.paintIcon(this, g,0, 0);

}

}