kaptcha 验证码在spring mvc 中的使用

kaptcha的配置是通过web.xml完成的，所有的参数都有默认值。

     所需要的jar包：kaptcha-2.0.jar

一、Kaptcha输出验证码的Demo：

二、配置参数（web.xml）

Xml代码  


<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>yes</param-value>  

    </init-param>  

</servlet>  

<servlet-mapping>  

    <servlet-name>Kaptcha</servlet-name>  

    <url-pattern>*.code</url-pattern>  

</servlet-mapping>  

 

三、在页面上的调用

Html代码  


<form action="submit.action">  

    <img src="validate.code" /> <input type="text" name="validateCode" value="" />  

</form>  

四、验证码的验证

Java代码  


HttpSession session = request.getSession();  

String makeValidateCode = (String) session  

        .getAttribute(Constants.KAPTCHA_SESSION_KEY);  

if (validateCode != null && makeValidateCode != null) {  

    return makeValidateCode.equalsIgnoreCase(validateCode);  

} else {  

    return false;  

}  

 五、实现刷新图片

       可以在请求URL后添加随机参数，避免浏览器的缓存。

Html代码  


<img src="validate.code" id="kaptchaImage" />  

<script type="text/javascript">  

    $(function(){  

        $('#kaptchaImage').click(function () {   

            $(this).attr('src', 'validate.code?' + Math.floor(Math.random()*100) ); })  

    });  

</script>  

<br /><small>Can't read the image? Click it to get a new one.</small>  

 

六、与spring MVC 的结合 

     在applicationContext.xml中添加

Java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 type="java.util.Properties">  

                                <value>kaptcha.border=yes</value>  

                        </constructor-arg>  

                </bean>  

        </property>  

</bean>  

 

源码：

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  

public class CaptchaImageCreateController {  

        private Producer captchaProducer = null;  

   

        @Autowired  

        public void setCaptchaProducer(Producer captchaProducer) {  

                this.captchaProducer = captchaProducer;  

        }  

   

        @RequestMapping("/captcha-image.html")  

        public ModelAndView handleRequest(  

                        HttpServletRequest request,  

                        HttpServletResponse response) throws Exception {  

                // Set to expire far in the past.  

                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;  

        }  

}   

 

Constant	Description	Default
kaptcha.border	Border around kaptcha. Legal values are yes or no.	yes
kaptcha.border.color	Color of the border. Legal values are r,g,b (and optional alpha) or white,black,blue.	black
kaptcha.border.thickness	Thickness of the border around kaptcha. Legal values are > 0.	1
kaptcha.image.width	Width in pixels of the kaptcha image.	200
kaptcha.image.height	Height in pixels of the kaptcha image.	50
kaptcha.producer.impl	The image producer.	com.google.code.kaptcha.impl.DefaultKaptcha
kaptcha.textproducer.impl	The text producer.	com.google.code.kaptcha.text.impl.DefaultTextCreator
kaptcha.textproducer.char.string	The characters that will create the kaptcha.	abcde2345678gfynmnpwx
kaptcha.textproducer.char.length	The number of characters to display.	5
kaptcha.textproducer.font.names	A list of comma separated font names.	Arial, Courier
kaptcha.textproducer.font.size	The size of the font to use.	40px.
kaptcha.textproducer.font.color	The color to use for the font. Legal values are r,g,b.	black
kaptcha.noise.impl	The noise producer.	com.google.code.kaptcha.impl.DefaultNoise
kaptcha.noise.color	The noise color. Legal values are r,g,b.	black
kaptcha.obscurificator.impl	The obscurificator implementation.	com.google.code.kaptcha.impl.WaterRipple
kaptcha.background.impl	The background implementation.	com.google.code.kaptcha.impl.DefaultBackground
kaptcha.background.clear.from	Starting background color. Legal values are r,g,b.	light grey
kaptcha.background.clear.to	Ending background color. Legal values are r,g,b.	white
kaptcha.word.impl	The word renderer implementation.	com.google.code.kaptcha.text.impl.DefaultWordRenderer
kaptcha.session.key	The value for the kaptcha is generated and is put into the HttpSession. This is the key value for that item in the session.	KAPTCHA_SESSION_KEY
kaptcha.session.date	The date the kaptcha is generated is put into the HttpSession. This is the key value for that item in the session.	KAPTCHA_SESSION_DATE