kaptcha 验证码在spring mvc 中的使用

kaptcha 是一个非常实用的验证码生成工具。有了它，你可以生成各种样式的验证码，因为它是可配置的。kaptcha工作的原理是调用 com.google.code.kaptcha.servlet.KaptchaServlet，生成一个图片。同时将生成的验证码字符串放到 HttpSession中。

使用kaptcha可以方便的配置：

 

• 验证码的字体
• 验证码字体的大小
• 验证码字体的字体颜色
• 验证码内容的范围(数字，字母，中文汉字！)
• 验证码图片的大小，边框，边框粗细，边框颜色
• 验证码的干扰线(可以自己继承com.google.code.kaptcha.NoiseProducer写一个自定义的干扰线)
• 验证码的样式(鱼眼样式、3D、普通模糊……当然也可以继承com.google.code.kaptcha.GimpyEngine自定义样式)

……

详细信息请看下面的web.xml文件

下面介绍一下用法:

1.首先去官网下载jar:http://code.google.com/p/kaptcha/

2.建立一个web项目，导入kaptcha-2.3.jar到环境变量中。

3.配置web.xml文件

 <!--Kaptcha 验证码  --> <!--
     < servlet >
         < servlet-name > kaptcha </ servlet-name >
         < servlet-class > com.google.code.kaptcha.servlet.KaptchaServlet </ servlet-class >
         < init-param >
             < param-name > kaptcha.border </ param-name >
             < param-value > no </ param-value >
         </ init-param >
         < init-param >
             < param-name > kaptcha.border.color </ param-name >
             < param-value > 105,179,90 </ param-value >
         </ init-param >
         < init-param >
             < param-name > kaptcha.textproducer.font.color </ param-name >
             < param-value > red </ param-value >
         </ init-param >
         < init-param >
             < param-name > kaptcha.image.width </ param-name >
             < param-value > 250 </ param-value >
         </ init-param >
         < init-param >
             < param-name > kaptcha.image.height </ param-name >
             < param-value > 90 </ param-value >
         </ init-param >
         < init-param >
             < param-name > kaptcha.textproducer.font.size </ param-name >
             < param-value > 70 </ param-value >
         </ init-param >
         < init-param >
             < param-name > kaptcha.session.key </ param-name >
             < param-value > code </ param-value >
         </ init-param >
         < init-param >
             < param-name > kaptcha.textproducer.char.length </ param-name >
             < param-value > 4 </ param-value >
         </ init-param >
         < init-param >
             < param-name > kaptcha.textproducer.font.names </ param-name >
             < param-value > 宋体,楷体,微软雅黑 </ param-value >
         </ init-param >
     </ servlet >

Xml代码

      < servlet-mapping >
 < servlet-name > kaptcha </ servlet-name >
 < url-pattern > /ClinicCountManager/kaptcha.jpg </ url-pattern >
 lt;/servlet-mapping>

 

jsp 页面使用

 <table>
         <tr>
             <td><img src="/ClinicCountManager/kaptcha.jpg" ></td>
             <td valign="top" >

                 <form method="POST" >
                     <br>sec code:<input type="text"  name= "kaptchafield" ><br />
                     <input type="submit"  name= "submit" >
                 </form>
             </td>
         </tr>
     </table>

     <br /><br /><br /><br />

     <%
         String c = (String)session.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
         String parm = (String) request.getParameter("kaptchafield" );

         out.println("Parameter: "  + parm +  " ? Session Key: "  + c +  " : " );

         if  (c !=  null  && parm !=  null ) {
             if  (c.equals(parm)) {
                 out.println("<b>true</b>" );
             } else  {
                 out.println("<b>false</b>" );
             }

     %>

 

上面的配置在普通jsp环境下面是有效的，如果在spring mvc环境下，则取不到session值，对于sping mvc环境验证码配置如下：

１.不用在web.xml进行相关配置，在applicationContext.xml中配置

 

Xml代码  

 < bean   id = "captchaProducer"   class = "com.google.code.kaptcha.impl.DefaultKaptcha" >
         < property   name = "config" >
             < bean   class = "com.google.code.kaptcha.util.Config" >
                 < constructor-arg >
                     < props >
                         < prop   key = "kaptcha.border" > no </ prop >
                         < prop   key = "kaptcha.border.color" > 105,179,90 </ prop >
                         < prop   key = "kaptcha.textproducer.font.color" > red </ prop >
                         < prop   key = "kaptcha.image.width" > 250 </ prop >
                         < prop   key = "kaptcha.textproducer.font.size" > 90 </ prop >
                         < prop   key = "kaptcha.image.height" > 90 </ prop >
                         < prop   key = "kaptcha.session.key" > code </ prop >
                         < prop   key = "kaptcha.textproducer.char.length" > 4 </ prop >
                         < prop   key = "kaptcha.textproducer.font.names" > 宋体,楷体,微软雅黑 </ prop >
                     </ props >
                 </ constructor-arg >
             </ bean >
         </ property >
     </ bean >

 

新建生成图片控制类

 import  java.awt.image.BufferedImage;
 import  javax.imageio.ImageIO;
 import  javax.servlet.ServletOutputStream;
 import  javax.servlet.http.HttpServletRequest;
 import  javax.servlet.http.HttpServletResponse;
 import  org.springframework.beans.factory.annotation.Autowired;
 import  org.springframework.stereotype.Controller;
 import  org.springframework.web.bind.annotation.RequestMapping;
 import  org.springframework.web.servlet.ModelAndView;
 import  com.google.code.kaptcha.Constants;
 import  com.google.code.kaptcha.Producer;

 @Controller
 @RequestMapping ( "/" )
 public   class  CaptchaImageCreateController {

     private  Producer captchaProducer =  null ;

     @Autowired
     public   void  setCaptchaProducer(Producer captchaProducer) {
         this .captchaProducer = captchaProducer;
     }

     @RequestMapping ( "/captcha-image" )
     public  ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response)  throws  Exception {

         response.setDateHeader("Expires" ,  0 );
         // Set standard HTTP/1.1 no-cache headers.
         response.setHeader("Cache-Control" ,  "no-store, no-cache, must-revalidate" );
         // Set IE extended HTTP/1.1 no-cache headers (use addHeader).
         response.addHeader("Cache-Control" ,  "post-check=0, pre-check=0" );
         // Set standard HTTP/1.0 no-cache header.
         response.setHeader("Pragma" ,  "no-cache" );
         // return a jpeg
         response.setContentType("image/jpeg" );
         // create the text for the image
         String capText = captchaProducer.createText();
         // store the text in the session
         request.getSession().setAttribute(Constants.KAPTCHA_SESSION_KEY, capText);
         // create the image with the text
         BufferedImage bi = captchaProducer.createImage(capText);
         ServletOutputStream out = response.getOutputStream();
         // write the data out
         ImageIO.write(bi, "jpg" , out);
         try  {
             out.flush();
         } finally  {
             out.close();
         }
         return   null ;
     }

 }

 前台调用方式

 

Java代码

 <div  class = "chknumber" >
        <label>验证码：
        <input name="kaptcha"  type= "text"  id= "kaptcha"  maxlength= "4"   class = "chknumber_input"  />
        </label>
         <img src="/ClinicCountManager/captcha-image.do"  width= "55"  height= "20"  id= "kaptchaImage"   style= "margin-bottom: -3px" />
        <script type="text/javascript" >
         $(function(){
             $('#kaptchaImage' ).click(function () { //生成验证码
              $(this ).hide().attr( 'src' ,  '/ClinicCountManager/captcha-image.do?'  + Math.floor(Math.random()* 100 ) ).fadeIn(); })
                   });

        </script>
      </div>

 取验证码的方式

 

Java代码

 String code = (String)session.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);