java ÖеÄÑéÖ¤Âë

<%@ page language="java" import="java.util.*" pageEncoding="GBK"
 import="java.awt.*,java.awt.image.*,javax.imageio.*"%><%
/*
ʹÓ÷½·¨£ºÔÚÐèÒªÏÔʾÑéÖ¤ÂëµÄhtml´úÂëÖÐʹÓÃ<img p">
  ÔÚÐèÅжÏsessionµÄʱºòÅжÏsession.getAttribute("vcode")
*/try{
  int codeLength=4;//ÑéÖ¤Â볤¶È
  int mixTimes=0;//Ä£ºý³Ì¶È²ÎÊý
  Color bgColor=getRandColor(200, 250);//±³¾°ÑÕÉ«
  Color bfColor=new Color(0,0,0);//×ÖÌåÑÕÉ«
  boolean ifRandomColor=true;//µ¥¸ö×Ö·ûÊÇ·ñÑÕÉ«Ëæ»ú
  boolean ifMixColor=true;//Ä£ºýÏßÊÇ·ñÑÕÉ«Ëæ»ú
  //ÉèÖÃÒ³Ãæ²»»º´æ
  // ÔÚÄÚ´æÖд´½¨Í¼Ïó
  int width = 13*codeLength+6, height = 20;
  BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);
  // »ñȡͼÐÎÉÏÏÂÎÄ
  Graphics g = image.getGraphics();
  // É趨±³¾°É«
  g.setColor(bgColor);
  g.fillRect(0, 0, width, height);
  //É趨×ÖÌå
  g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
  //»­±ß¿ò
  g.setColor(new Color(33,66,99));
  g.drawRect(0,0,width-1,height-1);
  // Ëæ»ú²úÉú¸ÉÈÅÏߣ¬Ê¹Í¼ÏóÖеÄÈÏÖ¤Âë²»Ò×±»ÆäËü³ÌÐò̽²âµ½
  g.setColor(getRandColor(160, 200));
  for (int i = 0; i < mixTimes*codeLength/10; i++) {
 if(ifMixColor)
 {
  g.setColor(getRandColor(160, 200));
 }
 int x = random.nextInt(width);
    int y = random.nextInt(height);
    int xl = random.nextInt(12);
    int yl = random.nextInt(12);
    g.drawLine(x, y, x + xl, y + yl);
  }
  // È¡Ëæ»ú²úÉúµÄÈÏÖ¤Âë(4λÊý×Ö)
  String sRand = "";
  for (int i = 0; i < codeLength; i++) {
    String rand = String.valueOf(random.nextInt(10));
    sRand += rand;
    // ½«ÈÏÖ¤ÂëÏÔʾµ½Í¼ÏóÖÐ
 if(ifRandomColor)
  g.setColor(getRandColor(20,110,0));
 else
  g.setColor(bfColor);
 //µ÷Óú¯Êý