下面是一个Applet程序,程序的功能是用鼠标点击画图。本题是通过点击鼠标后画出一个“Java”字。请改正程序中的错误(有下划线的语句),使程序能输出正确的结果。 注意:不改动程序的结构,不得增行或减行。 import java.awt.*; import java.awt.event.*; import java.applet.*; /* <applet code=SimpleHitMouse.java width=800 height=400> </applet> */ public class SimpleHitMouse implements Applet{ private java.util.Vector points=new java.util.Vector(); public void init(){ adclMouseListener(new MouseAdapter(){ public void mousePressed(MouseEvent e){ points.add(new Point (e.getX() ,e.getY())); paint ( ); } }); } public void update(Graphics g){ repaint(g); } public void paint(Graphics g){ for(int i=0;i<points.size();i++){ Point dot=(Point)points.elementAt(i); g.drawString('x',dot.x,dot.y); } } public static void main(String args[ ]){ Frame. fram=new Frame('CelayTree'); SimpleHitMouse dot=new SimpleHitMouse(); dot.init(); dot.start(); fram.add('Center',dot); fram.setSize(400,300); fram.addWindowListener(new WindowAdapter(){ public void windowClosing(WindowEvent e) {System.exit(0);} }); fram.show(); } } ex32_3.html: <html> <head> <title>A Simple Program</title> </head> <body> <applet code='SimpleHitMouse.class' width=800 height=400> </applet> </body> </html>