JSP中实现数字验证码源码（2）

数字验证码是一种最常用的验证字符码形式，以下为数字实现的JSP源码：   Num.jsp

<%@ 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(fc>255) cc=255;

if(bc>255) bb=255;

int r=cc+random.nextInt(bb-cc);

int g=cc+random.nextInt(bb-cc);

int b=cc+random.nextInt(bb-cc);

returnnew 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<4;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