kaptcha 验证码在spring mvc 中的使用

转自：http://ttaale.iteye.com/blog/808719

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>
  
      </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);