验证码的jsp页面

来源：互联网发布：离线观看老是检查网络编辑：程序博客网时间：2024/05/22 16:51

共两个页面

－－－－－－－ image.jsp -------------- <%@ page contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %>

<%!

Color getRandColor(int fc,int bc){//给定范围获得随机颜色

Random random = new Random();

if(fc>255) fc=255;

if(bc>255) bc=255;

int r=fc+random.nextInt(bc-fc);

int g=fc+random.nextInt(bc-fc);

int b=fc+random.nextInt(bc-fc);

return new Color(r,g,b);

}

//设置页面不缓存

//response.setHeader("Pragma","No-cache");

//response.setHeader("Cache-Control","no-cache");

//response.setDateHeader("Expires", 0);

// 在内存中创建图象

int width=60, height=20;

BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

// 获取图形上下文

Graphics g = image.getGraphics();

//生成随机类

Random random = new Random();

// 设定背景色

g.setColor(getRandColor(200,250));

g.fillRect(0, 0, width, height);

//设定字体

g.setFont(new Font("Times New Roman",Font.PLAIN,18));

//画边框

//g.setColor(new Color());

//g.drawRect(0,0,width-1,height-1);

// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到

g.setColor(getRandColor(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);

}

// 取随机产生的认证码(4位数字)

String sRand="";

for (int i=0;i<4;i++){

String rand=String.valueOf(random.nextInt(10));

sRand+=rand;

// 将认证码显示到图象中

g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成

g.drawString(rand,13*i+6,16);

}

// 将认证码存入SESSION

session.setAttribute("rand",sRand);

// 图象生效

g.dispose();

// 输出图象到页面

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

%>

－－－－－－ showimage.jsp----------------

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<title>My JSP 'showimage.jsp' starting page</title>

<!--

-->

</head>

<body>

This is my JSP page. <br>

</body>

</html>