該樓層疑似違規已被系統折疊?隱藏此樓查看此樓

利用java畫出橢圓。也就是鼠標一邊移動一邊顯示出橢圓，如何做到請大神指教

這是我寫的(沒有達到我自己的要求)：

import java.awt.*;

import java.awt.Graphics;

import java.awt.event.*;

import javax.swing.*;

import java.awt.Component;

public class Draw2 implements MouseMotionListener,MouseListener{

JFrame f;

int x1,x2,y1,y2;

mypane pane;

public static void main(String args[]){

Draw2 d=new Draw2();

d.go();

}

public void go(){

f=new JFrame("繪圖");

pane=new mypane();

pane.addMouseListener(this);

pane.addMouseMotionListener(this);

f.getContentPane().add(pane,"Center");

f.setSize(300,300);

f.setVisible(true);

}

public void mousePressed(MouseEvent e){

pane.repaint();

x1=e.getX();

y1=e.getY();

}

public void mouseDragged(MouseEvent e){

x2=e.getX()-x1;

y2=e.getY()-y1;

}

public void mouseMoved(MouseEvent e){

}

public void mouseReleased(MouseEvent e){

x2=e.getX()-x1;

y2=e.getY()-y1;

}

public void mouseEntered(MouseEvent e){}

public void mouseExited(MouseEvent e){}

public void mouseClicked(MouseEvent e){}

class mypane extends JPanel{

protected void paintComponent(Graphics g){

super.paintComponent(g);

g.drawOval(x1, y1, x2, y2);

}

}

}

該如何改？？？