kaptcha 验证码

kaptcha 验证码组件使用简介

 

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>

 

     <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

 <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

 <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

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

 如果需要全部数字

 <init-param>
     <param-name>kaptcha.textproducer.char.string</param-name>
     <param-value>0123456789</param-value>
 </init-param>

 去掉干扰线

 <init-param>
     <param-name>kaptcha.noise.impl</param-name>
     <param-value>com.google.code.kaptcha.impl.NoNoise </param-value>
 </init-param>