问JLabel通过mosemotionliistner控制，当另一个jlabel(不受鼠标控制)进入并离开JFrame时，它返回到原来的位置。

EN

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import sun.audio.*;
import java.io.*;
import java.util.Timer;
import java.util.TimerTask;
import java.awt.event.MouseEvent;

public class playFishGame extends JPanel implements MouseMotionListener {
   private JFrame board;// the main board
   private JLabel fish;
   private JLabel enemyFishS;
   private JLabel enemyFishS2;
   private JLabel enemyFishS3;
   private ImageIcon fishPic;
   private ImageIcon enemyFishSPic;
   private ImageIcon winBackground;
   private ImageIcon background;
   private ImageIcon loseBackground;
   ImageIcon fishSmall1r = new ImageIcon("data/fishSmall1r.png");
   ImageIcon fishSmall1l = new ImageIcon("data/fishSmall1l.png");
   ImageIcon fishSmall2r = new ImageIcon("data/fishSmall2r.png");
   ImageIcon fishSmall2l = new ImageIcon("data/fishSmall2l.png");
   ImageIcon fishSmall4r = new ImageIcon("data/fishSmall4r.png");
   ImageIcon fishSmall4l = new ImageIcon("data/fishSmall4l.png");
   private fish fishFish;
   private fish enemyFishSFish;
   private fish enemyFishSFish2;
   private fish enemyFishSFish3;
   private int origin;
   private boolean contact, win;
   Cursor blankCursor = null;

   public static void main(String args[]) {
      playFishGame play = new playFishGame();
   }

   public playFishGame() {
      blankCursor = Toolkit.getDefaultToolkit().createCustomCursor(
            Toolkit.getDefaultToolkit().createImage("data/blank.png"),
            new Point(0, 0), "blankCursor"); // blank.png is any tranparent
                                             // image.
      board = new JFrame("Play Fish Game");
      board.setSize(1300, 700);
      board.getContentPane().setCursor(blankCursor);
      board.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      board.add(this);// adds JLabel to JFrame
      this.addMouseMotionListener(this);
      board.setVisible(true);
      ImageIcon fishPic = new ImageIcon("data/sfr.gif");
      fish = new JLabel(fishPic);
      enemyFishS = new JLabel(" ");
      enemyFishS2 = new JLabel(" ");
      fishFish = new fish(617, 0);
      enemyFishSFish = new fish(1300, 350);
      enemyFishSFish2 = new fish(0, 500);
      // enemyFishSFish3= new fish(1300,200);
      this.add(fish);
      this.add(enemyFishS);
      this.add(enemyFishS2);
      contact = false;
      win = false;
      repaint();
      Timer timer = new Timer();
      timer.schedule(new TimerTask() {

         @Override
         public void run() {
            if (enemyFishSFish.initiate == true) {
               randomFishSmall(enemyFishSFish, enemyFishS);// picks image and
                                                           // starting
                                                           // point/side
               enemyFishSFish.initiate = false;
            }
            if (enemyFishSFish.chooseSide == 0) {
               enemyFishSFish.moveLeft();
               if (enemyFishSFish.getX() < 5) {
                  enemyFishSFish.initiate = true;
               }
            } else if (enemyFishSFish.chooseSide == 1) {
               enemyFishSFish.moveRight();
               if (enemyFishSFish.getX() > 1295) {
                  enemyFishSFish.initiate = true;
               }
            }
            if (enemyFishSFish2.initiate == true) {
               randomFishSmall(enemyFishSFish2, enemyFishS2);// picks image and
                                                             // starting
                                                             // point/side
               enemyFishSFish2.initiate = false;
            }
            if (enemyFishSFish2.chooseSide == 0) {
               enemyFishSFish2.moveLeft();
               if (enemyFishSFish2.getX() < 5) {
                  enemyFishSFish2.initiate = true;
               }
            } else if (enemyFishSFish2.chooseSide == 1) {
               enemyFishSFish2.moveRight();
               if (enemyFishSFish2.getX() > 1295) {
                  enemyFishSFish2.initiate = true;
               }
            }
            enemyFishS.setLocation(enemyFishSFish.getX(), enemyFishSFish.getY());
            contact(enemyFishSFish);
            enemyFishS2.setLocation(enemyFishSFish2.getX(),
                  enemyFishSFish2.getY());
            contact(enemyFishSFish2);

            // contact(enemyFishSFish);
            // enemyFishS2.setLocation(enemyFishSFish2.getX(),enemyFishSFish2.getY());
            // enemyFishS3.setLocation(enemyFishSFish3.getX(),enemyFishSFish3.getY());
         }
      }, 0, 100);
      board.setState(Frame.ICONIFIED);
      board.setState(Frame.NORMAL);
   }

   public void mouseMoved(MouseEvent evt) {
      System.out.println(evt.getPoint().x + ", " + evt.getPoint().y);

      if ((evt.getPoint().x < 1231) && (evt.getPoint().y < 623)) {
         fish.setLocation(evt.getPoint().x, evt.getPoint().y);
         fishFish.override(evt.getPoint().x, evt.getPoint().y);
      }
      Timer timer = new Timer();
      timer.schedule(new TimerTask() {

         @Override
         public void run() {
            origin = fishFish.getX();
         }
      }, 0, 100);
      int posneg = origin - evt.getPoint().x;
      ImageIcon sfr = new ImageIcon("data/sfr.gif");
      ImageIcon sfl = new ImageIcon("data/sfl.gif");
      ImageIcon mfr = new ImageIcon("data/mfr.gif");
      ImageIcon mfl = new ImageIcon("data/mfl.gif");
      if (posneg < 0) {
         if (fishFish.sFish < 10)
            fish.setIcon(sfr);
         if (fishFish.sFish > 9)
            fish.setIcon(mfr);
      }
      if (posneg > 0) {
         if (fishFish.sFish < 10)
            fish.setIcon(sfl);
         if (fishFish.sFish > 9)
            fish.setIcon(mfl);
      }

   }

   public void mouseDragged(MouseEvent evt) {
   }

   // 95/34
   public void contact(fish enemyFish) {
      if ((Math.abs(fishFish.getX() - enemyFish.getX())) < 48
            && (Math.abs(fishFish.getY() - enemyFish.getY()) < 36)
            && (fishFish.sFish < 10)) {
         fishFish.sFish++;
         enemyFish.initiate = true;
      }
   }

   public void paintComponent(Graphics g) {
      super.paintComponent(g);
      background = new ImageIcon("data/background3.png");
      winBackground = new ImageIcon("data/");
      loseBackground = new ImageIcon("data/");
      if ((contact == false) && (win == false))
         g.drawImage(background.getImage(), 0, 0, null);
      if (contact == true)
         g.drawImage(loseBackground.getImage(), 0, 0, null);
      if (win == true)
         g.drawImage(winBackground.getImage(), 0, 0, null);
   }

   public void randomFishSmall(fish changeFishFish, JLabel changeFish) {
      int chooseType = (int) (Math.random() * 3);
      // int chooseType=2;
      int chooseSide = (int) (Math.random() * 2);// left=0right=1
      int chooseSpeed = (int) (Math.random() * 12) + 6;
      int choosePlacement = (int) (Math.random() * 1288) + 15;
      changeFishFish.chooseType = chooseType;
      changeFishFish.chooseSide = chooseSide;
      changeFishFish.chooseSpeed = chooseSpeed;
      changeFishFish.choosePlacement = choosePlacement;
      if (chooseType == 0) {
         if (chooseSide == 0) {
            changeFish.setIcon(fishSmall1l);
            changeFishFish.override(1300, choosePlacement);
            // changeFishFish.
         } else {
            changeFish.setIcon(fishSmall1r);
            changeFishFish.override(0, choosePlacement);
         }
         changeFish.setLocation(changeFishFish.getX(), changeFishFish.getY());
      } else if (chooseType == 1) {
         if (chooseSide == 0) {
            changeFish.setIcon(fishSmall2l);
            changeFishFish.override(1300, choosePlacement);
         } else {
            changeFish.setIcon(fishSmall2r);
            changeFishFish.override(0, choosePlacement);
         }
         changeFish.setLocation(changeFishFish.getX(), changeFishFish.getY());
      } else if (chooseType == 2) {
         if (chooseSide == 0) {
            changeFish.setIcon(fishSmall4l);
            changeFishFish.override(1300, choosePlacement);
            // changeFishFish.
         } else {
            changeFish.setIcon(fishSmall4r);
            changeFishFish.override(0, choosePlacement);
         }
         changeFish.setLocation(changeFishFish.getX(), changeFishFish.getY());
      }
   }
}