web项目 验证码 *** 最爱那水货

1. jsp代码 ：

 <Script>
     function changeImg(){
                 document.getElementById("certImg").src ="makeCertPic.jsp?it="+Math.random();  /* +Math.random() */
             }
 </Script>

                         <table width="100%" border="0" cellspacing="1" cellpadding="1">
                             <tr>
                                 <td width="5%">&nbsp;</td>
                                 <td nowrap width="11%" align="left" class="loginname">验证码：

                                 </td>
                                 <td nowrap width="68%" class="loginname">
                                     <div align="left">
                                         <input type="text" istyle="input01" name="certCode"
                                             class="input01" />
                                         <!-- <iframe width="200" height="60" id="certImg" src="makeCertPic.jsp"></iframe> -->
                                         <img id="certImg" src="makeCertPic.jsp" onclick="changeImg()" alt="看不清换一张">
                                         <!-- onclick="changeImg()" alt="看不清换一张" -->

                                     </div>

                                 </td>

                             </tr>

                             <tr>
                                 <td width="14%">&nbsp;</td>

                                 <td nowrap width="18%" align="right" class="loginname">
                                     <div align="left">用户名：</div>
                                 </td>
                                 <td nowrap width="68%" class="loginname">
                                     <div align="left">
                                         <html:text styleClass="input01" property="user_code"
                                             onkeypress="return handleEnter(this, event,1)" />
                                         <!-- <a href="#" onclick="changeImg()">看不清换一张 </a> -->
                                     </div>
                                 </td>
                             </tr>
                             <tr>
                                 <td width="14%">&nbsp;</td>
                                 <td nowrap width="18%" align="right" class="loginname">
                                     <div align="left">密&nbsp;&nbsp;码：</div>
                                 </td>
                                 <td nowrap width="68%" class="loginname">
                                     <div align="left">
                                         <html:password styleClass="input01" property="password"
                                             value="" />
                                     </div>
                                 </td>

                             </tr>

                             <tr>

                                 <td align="left">
                                 <td nowrap align="right"><html:submit value='登　录'
                                         styleClass="button" onclick="return ck_login();" /></td>
                                 <td nowrap align="left"><html:reset value='重　写'
                                         styleClass="button" /></td>
                                 </td>
                             </tr>
                         </table>

2.链接的加jsp文件，用于加载验证码数据

 <%@page import="com.test.makeCertPic"%>
 <%@ page language="java" import="java.util.*" pageEncoding="GBK"%>
 <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
 <%@page contentType="image/jpeg" %>

  <%
      makeCertPic pic = new makeCertPic();
      String str = pic.getCertPic(0, 0, response.getOutputStream());
      session.setAttribute("certCode", str);
      //关闭response ，不加会运行两次，且会报错
      out.clear();
      out = pageContext.pushBody();
  %>

3.对应的验证码类 java代码

 package com.test;

 import java.awt.Color;
 import java.awt.Font;
 import java.awt.Graphics;
 import java.awt.image.BufferedImage;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Random;
 import javax.imageio.ImageIO;

 /**
  * @author dzy 生成验证码图片
  */
 public class makeCertPic {
     // 验证码图片中可以出现的字符集，可根据需要修改
     private char mapTable[] = { '0','1', '2', '3', '4', '5', '6', '7', '8','9' };

     /**
      * 功能:生成彩色验证码图片 参数width为生成图片的宽度,参数height为生成图片的高度,参数os为页面的输出流
      */
     public String getCertPic(int width, int height, OutputStream os) {
         if (width <= 0)
             width = 60;
         if (height <= 0)
             height = 20;
         BufferedImage image = new BufferedImage(width, height,
                 BufferedImage.TYPE_INT_RGB);
         // 获取图形上下文
         Graphics g = image.getGraphics();
         // 设定背景色
         g.setColor(new Color(0xDCDCDC));
         g.fillRect(0, 0, width, height);
         // 画边框
         g.setColor(Color.black);
         g.drawRect(0, 0, width - 1, height - 1);
         // 取随机产生的认证码
         String strEnsure = "";
         // 4代表4位验证码,如果要生成更多位的认证码,则加大数值
         for (int i = 0; i < 4; ++i) {
             strEnsure += mapTable[(int) (mapTable.length * Math.random())];
         }
         // 将认证码显示到图像中,如果要生成更多位的认证码,增加drawString语句
         g.setColor(Color.black);
         g.setFont(new Font("Atlantic Inline", Font.PLAIN, 18));
         String str = strEnsure.substring(0, 1);
         g.drawString(str, 8, 17);
         str = strEnsure.substring(1, 2);
         g.drawString(str, 20, 15);
         str = strEnsure.substring(2, 3);
         g.drawString(str, 35, 18);
         str = strEnsure.substring(3, 4);
         g.drawString(str, 45, 15);
         // 随机产生10个干扰点
         Random rand = new Random();
         for (int i = 0; i < 10; i++) {
             int x = rand.nextInt(width);
             int y = rand.nextInt(height);
             g.drawOval(x, y, 1, 1);
         }
         // 释放图形上下文
         g.dispose();
         try {
             // 输出图像到页面
             ImageIO.write(image, "JPEG", os);
         } catch (IOException e) {
             return "";
         }
         return strEnsure;
     }
 }

项目中的 验证码 尤其注意登陆时会被项目的filter类过滤排除，导致验证码加载不出来 ，需要在web.xml中 进行jsp的自定义过滤

本项目中设置filter的xml文件 和 过滤的java代码如下：

     <filter>
         <filter-name>BtSystemFilter</filter-name>
         <filter-class>com.bettersoft.filters.BtSystemFilter</filter-class>
     </filter>
     <filter-mapping>
         <filter-name>BtSystemFilter</filter-name>
         <url-pattern>/*</url-pattern>
     </filter-mapping>

 public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {
         HttpServletRequest request = (HttpServletRequest) req;
         HttpServletResponse response = (HttpServletResponse) resp;
          HttpSession session = request.getSession();
         String uri = request.getRequestURI();
          String projectName = request.getContextPath();
          String url=uri.substring(projectName.length());
         try
         {
             if( uri.startsWith(projectName + "/services")
                     || uri.startsWith(projectName + "/axis2-web"))                //webservice
             {
                 chain.doFilter(req, resp);
                 }
               //过滤.jsp和.do
             else if (uri.endsWith(".jsp")|| uri.endsWith(".do"))
             {
              //如果为系统登录类型资源不进行session检查
              if((uri.equals(projectName+"/index.jsp"))
                  ||uri.equals(projectName+"/login.jsp")
                  ||uri.equals(projectName+"/main.jsp")
                  ||uri.equals(projectName+"/login.do")
                  ||uri.equals(projectName+"/showTRCA.jsp")//用证书登录时选择证书
                  ||uri.equals(projectName+"/bindCA.jsp")//用证书登录时绑定证书
                  ||uri.equals(projectName+"/error.jsp")
                  ||uri.equals(projectName+"/makeCertPic.jsp")//验证码
                  )
              {
                  chain.doFilter(req, resp);
              }
              else
              {   //session失效或未登录
                  if (session.getAttribute("com.bettersoft.admin.userbean") == null)
                  { response.sendRedirect(projectName + "/login.jsp?nologin=nologin");
                   }
                  else
                  {   //如果当前资源是系统菜单
                      if(CheckUserUtil.isSyeRes(url))
                      {
                         if(CheckUserUtil.hasPermission(request, url))
                         {
                             chain.doFilter(req, resp);
                         }
                         else
                         {
                             response.sendRedirect(projectName + "/login.jsp?nologin=invalidurl");
                         }
                      }
                      else
                      {
                          chain.doFilter(req, resp);
                      }     

                  }
              }
             }else
             {
             chain.doFilter(req, resp);
             }
          }
         catch(Exception e)
         {    e.printStackTrace();
              String  errormsg="未知的系统异常";
              if(e.getMessage()!=null)
                  {
                  //if(e.getMessage().length()<50)
                  errormsg=e.getMessage();
                  }
              request.setAttribute("errormsg",errormsg);
              request.getRequestDispatcher("/error.jsp").forward(request, response);
         }
     }

最后的效果图