最基础的applet运用--在applet上画线

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class DrawLine extends JApplet implements 

MouseListener,MouseMotionListener{
    int x1,y1,x2,y2;
//    int screenx,screeny;
//    Dimension screen;
    Stroke sk=new BasicStroke(2.0f);
    public void init(){
//        screen=Toolkit.getDefaultToolkit().getScreenSize

();
//        screenx=(int)screen.getWidth();
//        screeny=(int)screen.getHeight();
//        setBounds((screenx-400)/2, (screeny-700)/2, 400, 

700);
        addMouseListener(this);
        addMouseMotionListener(this);
    }
    public void paint(Graphics g){
        Graphics2D gg=(Graphics2D)g;
        gg.setStroke(sk);
        gg.drawLine(x1, y1, x2, y2);
    }
    @Override
    public    void mouseClicked(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseEntered(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseExited(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }

    public void mousePressed(MouseEvent arg0) {
        //x1=arg0.getX();
        //y1=arg0.getY();
    }

    @Override
    public void mouseReleased(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseDragged(MouseEvent arg0) {
        x2=arg0.getX();
        y2=arg0.getY();
        x1=x2;
        y1=y2;
        repaint();
    }

    @Override
    public void mouseMoved(MouseEvent arg0) {

        Point p=new Point(x2,y2);
        System.out.println(p);
        //System.out.println("Y"+this.y2);
    }
}