如何在JPanel中套入一个JPanel？或有更适合的容器？

1）绘图一般子类化 JComponent ，不采用 jpanel 的原因是：Jpanel 带有更多的成员，所以导致类体积增加，我们的目的仅为绘图，无需他用。
2）绘图的时候，可以采用如下思路：
采用 BufferedImage 保存绘图板上的内容，对绘图内容的操作本质上就变成了对BufferedImage的操作。需要刷新到屏幕的时候就直接把 BufferedImage 刷出去就可行

附上代码，学习简洁的代码风格与结构

import javax.swing.*;
import java.awt.*;
import java.awt.geom.*;
import java.awt.event.*;
import java.awt.image.*;
/**
* @author Hardneedl
*/
class ImageGraphicsDemo extends JFrame {
private static final Dimension minSize = new Dimension(300, 200);
private static final Dimension maxSize = new Dimension(1024, 768);
private static final Dimension preferredSize = new Dimension(600, 400);
public Dimension getMaximumSize() {return maxSize;}
public Dimension getMinimumSize() {return minSize;}
public Dimension getPreferredSize() {return preferredSize;}
public boolean isResizable() {return false;}
public String getTitle() {return "Frame Title";}
private JComponent canvas = new JComponent(){
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D gg = (Graphics2D)g.create();
gg.drawImage(bufImage,0,0,this);
gg.dispose();
}
};
private BufferedImage bufImage;
ImageGraphicsDemo() throws HeadlessException {
init();
doLay();
attachListeners();
}

private void init() {
bufImage = new BufferedImage(preferredSize.width,preferredSize.height,BufferedImage.TYPE_INT_RGB);
}

private void doLay() {
getContentPane().add(new JButton(new DrawRectangleAction()),BorderLayout.NORTH);
getContentPane().add(canvas,BorderLayout.CENTER);
pack();
}

private void attachListeners() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

private class DrawRectangleAction extends AbstractAction {
private static final int STEP = 25;
private Rectangle rct = new Rectangle(10,10,20,30);
private AffineTransform affine = new AffineTransform();
private DrawRectangleAction() {
super("Draw Rectangle");
putValue(Action.MNEMONIC_KEY, Integer.valueOf('D'));
}
public void actionPerformed(ActionEvent e) {
Graphics2D g = (Graphics2D)bufImage.getGraphics();
g.setColor(Color.PINK);
affine.translate(STEP,STEP);
g.setTransform(affine);
g.draw(rct);
g.dispose();
if(canvas.isVisible()) canvas.paintImmediately(canvas.getBounds());
}
}
public static void main(String[] args) {new ImageGraphicsDemo().setVisible(true);}
}

方法一：去继承jpanel，重写这个方法
方法二：创建jpanel的时候，用匿名类重写：
jpanel
pane
=
new
jpanel(layoutmanager
layout)
{
protected
void
paintcomponent(graphics
g)
{
//code.....
}
};
希望对你有帮助