如何实现鼠标拖曳

调试编译通过了，可直接运行import javax.swing.*;
import java.awt.*;import java.awt.event.*;
import java.awt.image.ImageObserver;
import java.util.Vector;
import java.net.URL;
public class ButtonMove extends JFrame
{
  JButton jButton1 = new JButton();
  int focusx=0;
  int focusy=0;    public ButtonMove()
    {
        try
        {
          jbInit();
        }
        catch(Exception e)
        {
          e.printStackTrace();
        }
    }
    private void jbInit() throws Exception
    {
        jButton1.setBounds(new Rectangle(86, 113, 73, 25));
        jButton1.setText("jButton1");
        jButton1.addMouseListener(new MouseProcess(){});
        jButton1.addMouseMotionListener(new MouseMotionProcess());        this.setLocale(java.util.Locale.getDefault());
        this.getContentPane().setLayout(null);
        this.getContentPane().add(jButton1, null);
        this.setSize(400,500);
        this.setVisible(true);
    }    private class MouseProcess extends MouseAdapter
       {
           public void mouseClicked(MouseEvent e)
           {
           }           public void mousePressed(MouseEvent e)
           {
               focusx = e.getX(); focusy = e.getY();
           }       }       private class MouseMotionProcess extends MouseMotionAdapter
       {
           public void mouseDragged(MouseEvent e)
           {
               Container container = jButton1.getParent();
               int w = container.getWidth();
               int h = container.getHeight();               int x = jButton1.getX()+e.getX()-focusx;
               int y = jButton1.getY()+e.getY()-focusy;               if( x+jButton1.getWidth() > w ) x = w-jButton1.getWidth();
               if( y+jButton1.getHeight() > h ) y = h-jButton1.getHeight();
               if( x < 0 ) x = 0;
               if( y < 0 ) y = 0;               jButton1.setLocation(x, y);
               jButton1.setLocation(x,y+jButton1.getHeight());
               container.repaint();
               container = null;
           }
       }       public static void main(String args[]){
            new ButtonMove();
        }
}