kaptcha验证码的使用

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验证码配置 -->
  <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.obscurificator.impl</param-name>  
            <param-value>com.google.code.kaptcha.impl.FishEyeGimpy</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>  
          <!-- String kaptchaExpected = (String) session.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);  
                     必须改成
                    String kaptchaExpected = (String) session.getAttribute("code"); -->
            <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>/kaptcha</url-pattern>
</servlet-mapping>

4. jsp 页面使用

<form class="m-t" role="form"  id="loginform" method="post" action="">
                <div class="form-group"><input class="form-control"  name="userAccount" placeholder="用户名" required=""></div>
                <div class="form-group"><input type="password" class="form-control"   name="userPwd"  placeholder="密码" required=""></div>
                <input type="text" class="form-control login-yan-w" id="kaptcha" name="kaptcha" placeholder="验证码">
                 <span class="login-w"><img id="kaptchaImage" src="kaptcha"></span>
                <input type="button"  class="btn btn-primary block full-width m-b" onclick="login()"  value="登 录">
            </form>

function login(){
        $.ajax({
            cache: true,
            type: "POST",
            url:'${pageContext.request.contextPath}/login',
            data:$('#loginform').serialize(),
            dataType:'json',
            success: function(data) {
                if(data.status==200){
                    url="<%=request.getContextPath()%>/index.jsp";
                    window.location.href=url;               
                }else{
                    alert(data.msg)
                }
            },
            error: function(){                 
                alert("请检查用户账户或密码");
            }
        });
        }

5. 如果想设置点击图片更换验证码，可以加上如下js

<script type="text/javascript">
    //点击图片验证码进行更新
    $(function(){
        $('#kaptchaImage').click(function () { $(this).attr('src', 'kaptcha?' + Math.floor(Math.random()*100) ); })
    });
</script>

5. KaptchaServlet会把验证码设置到session中，在Controller可以如下方式获取

@RequestMapping("/login")
@ResponseBody
public CRMResult  login(HttpServletRequest request ,HttpSession session) {
    String kaptcha = request.getParameter("kaptcha");
    String kaptchaExpected = (String) session.getAttribute("code");
    System.out.println(kaptcha +"......"+kaptchaExpected);
    if (!kaptcha.equalsIgnoreCase(kaptchaExpected)) {
        return CRMResult.build(201, "验证码填写错误");
    }
    return CRMResult.ok();
}

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springmvc.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>  

Java代码  

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>