希望代码示例中的注释能够告诉您您在代码中做错了什么:-)，否则总有理由提出您的疑问…
import java.awt.*;import javax.swing.*;import java.awt.event.*;public class Game extends JPanel { private int x; private int y; private MouseAdapter mouseActions = new MouseAdapter() { @Override public void mouseMoved(MouseEvent me) { x = me.getX(); y = me.getY(); repaint(); } }; //JPanel panel; // Not needed for this case. //JButton button2; //JButton button; public void game() { Jframe frame = new Jframe("Game"); frame.setDefaultCloseOperation(Jframe.DISPOSE_ON_CLOSE); frame.setResizable(false); addMouseMotionListener(mouseActions); frame.add(this); frame.pack(); frame.setLocationByPlatform(true); frame.setVisible(true); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); g.fillRect(x, y, 100, 100); } public static void main(String[] args) { Runnable runnable = new Runnable() { @Override public void run() { new Game().game(); } }; EventQueue.invokeLater(runnable); } @Override public Dimension getPreferredSize() { return new Dimension(500, 500); }}
