为了在单位正方形里面画一个洞 ，网上获取了此代码。

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.awt.geom.*;
import javax.swing.*;

public class getxy2
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(new Runnable()
         {
            public void run()
            {
               MouseFrame frame = new MouseFrame();
               frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
               frame.setVisible(true);
            }
         });
   }
}

class MouseFrame extends JFrame
{
   public MouseFrame()
   {
      setTitle("MouseTest");
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      // add component to frame

      MouseComponent component = new MouseComponent();
      add(component);
   }

   public static final int DEFAULT_WIDTH = 500;
   public static final int DEFAULT_HEIGHT = 500;
}

class MouseComponent extends JComponent
{
   public MouseComponent()
   {
     
      addMouseListener(new MouseHandler());
      
   }
private class MouseHandler extends MouseAdapter
   {
      

      public void mouseClicked(MouseEvent event)
      {
        
         System.out.println(event.getPoint().getX()/500+" "
         +event.getPoint().getY()/500+" "+0.0);
         
   }
}
}