java--jsp图片验证码

来源：互联网发布：郭德纲人品知乎编辑：程序博客网时间：2024/06/03 17:41
原文转自：http://blog.csdn.net/chinasoftosg/article/details/8027215
verifycode.jsp
<span style="font-size:18px;"><%@page contentType="image/JPEG" language="java" import= "crm.util.RandomNumUtil" pageEncoding="utf-8"%><%@page import="javax.imageio.ImageIO,java.awt.*,java.util.*,java.awt.image.BufferedImage"%><%!//图像BufferedImage image;//验证码String randCode;%><%!Color getRandColor(int fc,int bc){    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;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.fillRect(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)for (int i=0;i<4;i++){    String rand=String.valueOf(random.nextInt(10));    randCode+=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);    }session.setAttribute("code",randCode);//图象生效g.dispose();ImageIO.write(image,"JPEG",response.getOutputStream());%><%    out.clear();                  /* This Sentence Is Necessary */    out = pageContext.pushBody(); /* This Sentence Is Necessary */%>login.jsp<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <title>登陆界面</title>     </head>   <body>     <img src="<%=basePath%>pages/verifycode2.jsp"/>  </body></html></span>
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