Java重新绘制JButton

正常状态：

获得焦点状态：

被按下状态：

被释放状态：

实现代码：

[java]
package com.han;

import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RadialGradientPaint;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.font.LineMetrics;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferedImage;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.UIManager;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.UnsupportedLookAndFeelException;

@SuppressWarnings("serial")
public class JButton_Bg extends JFrame {

    public JButton_Bg() {
        for (LookAndFeelInfo laf : UIManager.getInstalledLookAndFeels()) {
            if (laf.getName().equals("Nimbus")) {
                try {
                    UIManager.setLookAndFeel(laf.getClassName());
                } catch (ClassNotFoundException | InstantiationException
                        | IllegalAccessException
                        | UnsupportedLookAndFeelException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
        // TODO Auto-generated constructor stub
        Container c = getContentPane();
        c.setLayout(new FlowLayout());

        final JButton button = new MyButton("button 2");

        c.add(button);
        JButton button2 = new JButton("button 2");
        c.add(button2);
        button2.setBackground(Color.blue);

        JButton button3 = new MyButton2("Cancel");
        c.add(button3);

        // 完全重绘的Button，其Text的HTML设置特性消失
        // JButton button4 = new
        // MyButton3("<html><font size=12>Sub</font></html>");
        JButton button4 = new MyButton3("Sub");
        // button4.setFont(new Font("Serif", Font.PLAIN, 14));
        c.add(button4);
    }

    private class MyButton extends JButton {
        private String text;
        private String state = "normal";
//      private String state = "focused";
//      private String state = "pressed";
//      private String state = "released";

        // 无参构造继承时自动调用，而有参构造继承时则需手动重写
        MyButton(String text) {
            // super("<html><font size=5>" + text + "</font></html>");
            super(text);
            this.text = text;

            // 下面的代码块若是放到下面的paintComponent()方法里则Swing界面初始化时，
            // 布局管理器还是采用的是系统默认的PreferredSize。因为构造函数要优先于
            // paintComponent()方法执行。
            Dimension preferredSize = getPreferredSize();
            Dimension preferredSizeNew = new Dimension(preferredSize.width,
                    preferredSize.width);
            setPreferredSize(preferredSizeNew);
        }

        @Override
        protected void paintComponent(Graphics g) {
            Graphics2D g2 = (Graphics2D) g;
            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                    RenderingHints.VALUE_ANTIALIAS_ON);

            int width = this.getPreferredS

补充：软件开发 , Java ,