<%@ page contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %> 
<%!
 
    Color getRandColor(int cc,int bb)
 
    {
 
        Random random = new Random();
 
        if(cc>255) cc=255;
 
        if(bb>255) bb=255;
 
        int r=cc+random.nextInt(bb-cc);
 
        int g=cc+random.nextInt(bb-cc); 
 
        int b=cc+random.nextInt(bb-cc);
 
        return new Color(r,g,b);
 
    } //获取随机颜色

 
%>
 
<%
 
    response.setHeader("Pragma","No-cache");
 
    response.setHeader("Cache-Control","no-cache");
 
    response.setDateHeader("Expires", 0);

 
 
    int width=80; //定义验证码图片的长度
 
    int height=30; //定义验证码图片的宽度
 
    BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
 
 
 
    Graphics g = image.getGraphics();
 
 
 
    Random random = new Random();
 
 
 
    g.setColor(getRandColor(200,250));
 
    g.fillRect(0, 0, width, height);
 
 
 
    g.setFont(new Font("Times New Roman",Font.PLAIN,18));

 
    //定义字体形式
 
 
    g.setColor(getRandColor(160,200));
 
    for (int i=0;i<155;i++)
 
    {
 
       int i_x = random.nextInt(width);
 
       int i_y = random.nextInt(height);
 
       int i_xl = random.nextInt(12);
 
       int i_yl = random.nextInt(12);
 
       g.drawLine(i_x,i_y,i_x+i_xl,i_y+i_yl);
 
    }

 
    //用线条画背景
 
 
    String s_Rand="";
 
    for (int i=0;i<5;i++)
 
    {
 
       String rand=String.valueOf(random.nextInt(10));
 
       s_Rand+=rand;
 
       

       g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
 
       g.drawString(rand,13*i+6,16);
 
    }

 
    //产生4位随机码 
 
 
    session.setAttribute("rand",s_Rand);

 
    //将验证码存入Session中
 
 
    g.dispose();
 
    

    ImageIO.write(image, "JPEG", response.getOutputStream());

 
    //输出验证图片
    

    out.clear();
 
    out = pageContext.pushBody();
 
    

%>