swing 中怎么改变按钮的形状

public class MyButton extends JButton {     public MyButton() {     }    public void paintComponent(Graphics g) {        super.paintComponent(g);        g.drawArc(0,0,20,20);//可以自己绘制    }}
------解决方案--------------------
下面是swing里面自带的改表变外观的:

UIManager.setLookAndFeel(new LookAndFeel());  
JFrame.setDefaultLookAndFeelDecorated(true);  
JDialog.setDefaultLookAndFeelDecorated(true);  


还有就是一个项目做了一个提供流行的外观(look&feel)

一些好看的look and feel


.Substance  
这个项目的目的是提供一个流行的外观（look & feel）。这个外观（look & feel）联合了Windows XP和MacOS 10.4最好的特性并且需要JDK 5.0以上  

将下列jar文件拷贝到你的程序的classpath中，然后将下列代码段加入到你main函数中  
http://l1.edn.cn/cache/http/index.php?q=http%3A%2F%2F210.42.106.102%2Fbbs%2Fviewthread.php%3Ftid%3D111%26amp%3Bextra%3Dpage%253D1  
（注，其实我在别的文章中给出了一个例子，参见用java打造任意形状窗口一文中的的代码）  
1.substance look and feel:  
try {  
UIManager.setLookAndFeel(new SubstanceLookAndFeel());  
UIManager.put("swing.boldMetal", false);  
if (System.getProperty("substancelaf.useDecorations") == null) {  
JFrame.setDefaultLookAndFeelDecorated(true);  
JDialog.setDefaultLookAndFeelDecorated(true);  
}  
System.setProperty("sun.awt.noerasebackground", "true");  
SubstanceLookAndFeel.setCurrentTheme(new SubstanceLightAquaTheme());//设置当前的主题风格，同样我 们还可以设置当前的按钮形状，水印风格等等  
} catch (Exception e) {  
System.err.println("Oops! Something went wrong!");  
}  


2.smooth look and feel  
try {  
UIManager.setLookAndFeel(new SmoothLookAndFeel());  
UIManager.put("swing.boldMetal", false);  
} catch (Exception e) {  
System.err.println("Oops! Something went wrong!");  
}  


3. office/winxp/VisualStudio 2005 look and feel  
try {  
UIManager.setLookAndFeel("org.fife.plaf.Office2003.Office2003LookAndFeel");  
//UIManager.setLookAndFeel("org.fife.plaf.OfficeXP.OfficeXPLookAndFeel");  
//UIManager.setLookAndFeel("org.fife.plaf.VisualStudio2005.VisualStudio2005LookAndFeel");  
UIManager.put("swing.boldMetal", false);  
} catch (Exception e) {  
System.err.println("Oops! Something went wrong!");  
}


参考资料：http://www.blogjava.net/dyerac/archive/2006/04/03/38986.html

------解决方案--------------------
C/C++ code
Java绘制自定义按钮, 写了三种情况的， 当然还有其他的， 可以参考一下， 其实主要就是paintComponent和一些细节：import javax.swing.*;import java.awt.*;import java.awt.event.*;public class Test01 {    public static void main(String args[]) {        JFrame frame = new JFrame();        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        frame.setSize(300,                300);        JPanel panel = new JPanel();        JButton button = new MyButton2("Button");        button.setFocusable(false);        button.setBorderPainted(false);        button.addActionListener(new ActionListener() {            public void actionPerformed(ActionEvent e) {                System.out.println("Button is clicked");            }        });        panel.add(button);        frame.getContentPane().add(panel);        frame.setVisible(true);    }}class MyButton2 extends JButton {    private static final long serialVersionUID = 1965063150601339314L;    public MyButton2(String text) {        super(text);        setOpaque(false);        setContentAreaFilled(false); // 这一句非常重要, 否则父类还会绘制按钮的区域.    }    @Override    protected void paintComponent(Graphics g) {        int width = this.getWidth();        int height = this.getHeight();        Graphics2D g2d = (Graphics2D) g;        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,                RenderingHints.VALUE_ANTIALIAS_ON);        g2d.setColor(Color.GRAY);        g2d.fillRoundRect(0,                0,                width,                height,                20,                20);        super.paintComponent(g); // 最后调用这个方法, 让父类绘制在按钮上绘制文字.    }}Blur一个按钮:class MyButton2 extends JButton {    private static final long serialVersionUID = 1965063150601339314L;    public MyButton2(String text) {        super(text);        // setOpaque(false);        // setContentAreaFilled(false); // 这一句非常重要, 否则父类还会绘制按钮的区域.    }    @Override    protected void paintComponent(Graphics g) {        BufferedImage buf = new BufferedImage(getWidth(), getHeight(),                BufferedImage.TYPE_INT_RGB);        super.paintComponent(buf.getGraphics());        float[] my_kernel = { 0.10f, 0.10f, 0.10f, 0.10f, 0.20f, 0.10f, 0.10f,                0.10f, 0.10f };                ConvolveOp op = new ConvolveOp(new Kernel(3, 3, my_kernel));        Image img = op.filter(buf,                null);        g.drawImage(img,                0,                0,                null);    }}class ImageButton extends JButton {    private static final long serialVersionUID = 1965063150601339314L;    Image image = new ImageIcon("v4.png").getImage();    public ImageButton(String text) {        super(text);        setOpaque(false);        setFocusable(false);        setBorderPainted(false);        this.setPreferredSize(new Dimension(image.getWidth(this), image                .getHeight(this)));    }    @Override    protected void paintComponent(Graphics g) {        g.drawImage(image,                0,                0,                null);    }}