问如何在java中把图片放到jslilder的swing旋钮上？

EN

package java_sandbox;

import javax.imageio.ImageIO;
import javax.swing.JSlider;
import javax.swing.SwingUtilities;
import javax.swing.JFrame;
import javax.swing.plaf.basic.BasicSliderUI;

import java.awt.*;

import java.io.File;
import java.io.IOException;


public class CustomSliderKnob {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new CustomSliderKnob(); 
            }
        });
    }

    public CustomSliderKnob() {

        JFrame f = new JFrame( "Swing Slider Knob" );
        f.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE ); 


        Container p = f.getContentPane();
        JSlider s = new JSlider();

        s.setUI( new mySliderUI( s ) );

        p.add( s );

        f.pack();
        f.setVisible(true);
    } 

    private class mySliderUI extends BasicSliderUI {

        Image knobImage;

        public mySliderUI( JSlider aSlider ) {

            super( aSlider );

            try {
                this.knobImage = ImageIO.read( new File( "d:\\d.jpg") );

            } catch ( IOException e ) {

                e.printStackTrace();
            }
        }
        public void paintThumb(Graphics g)  {        

            g.drawImage( this.knobImage, thumbRect.x, thumbRect.y, 8, 8, null );

        }

    }

}

Icon icon = new ImageIcon("slider.png");
        UIDefaults defaults = UIManager.getDefaults();
        defaults.put("Slider.horizontalThumbIcon", icon);