验证码--jsp

<%@ page
 contentType="image/jpeg"
 import="java.awt.image.*,java.awt.*,java.util.*,javax.imageio.*"
%>
<%!
    public Color getRandomColor(int firstcolor,int secondcolor)
    {
        Random random = new Random();
        if(firstcolor>255) firstcolor=255;
        if(secondcolor>255) secondcolor=255;
        int r=firstcolor+random.nextInt(secondcolor-firstcolor);
        int g=firstcolor+random.nextInt(secondcolor-firstcolor);
        int b=firstcolor+random.nextInt(secondcolor-firstcolor);
        return new Color(r,g,b);
   }
%>
<%
  int width=60,height=20;
  BufferedImage image=new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); 
  Graphics g= image.getGraphics(); 
  Random random=new Random();
  g.setColor(getRandomColor(200,250));
  g.fillRect(0, 0, width, height); 
  g.setFont(new Font("Times New Roman",Font.PLAIN,18)); 
  g.setColor(getRandomColor(160,200));
  for (int i=0;i<155;i++)
  {
    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);
  }
  String yanZhengMa="";
  for (int i=0;i<4;i++){
   int leixing=random.nextInt(62);
   String yanzhengmatemp="r";
   if(leixing<10)
   {
    yanzhengmatemp=String.valueOf(random.nextInt(10));
   }
   else if(leixing<36)
   {
    yanzhengmatemp=((char)(random.nextInt(122-97)+97))+"";
   }
   else
   {
    yanzhengmatemp=((char)(random.nextInt(90-65)+65))+"";
   }
      yanZhengMa+=yanzhengmatemp;
      g.setColor(new Color(25+random.nextInt(110),25+random.nextInt(110),25+random.nextInt(110)));
   g.drawString(yanzhengmatemp,13*i+6,16);
  }
 
  session.setAttribute("yanzhengma",yanZhengMa.toLowerCase());
  g.dispose();
  ImageIO.write(image, "JPEG", response.getOutputStream());
%>