kaptcha 验证码在spring mvc 中的使用

来源：互联网发布：js特效代码大全编辑：程序博客网时间：2024/05/16 13:00

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;  
        }  
}   

ConstantDescriptionDefaultkaptcha.borderBorder around kaptcha. Legal values are yes or no.yeskaptcha.border.colorColor of the border. Legal values are r,g,b (and optional alpha) or white,black,blue.blackkaptcha.border.thicknessThickness of the border around kaptcha. Legal values are > 0.1kaptcha.image.widthWidth in pixels of the kaptcha image.200kaptcha.image.heightHeight in pixels of the kaptcha image.50kaptcha.producer.implThe image producer.com.google.code.kaptcha.impl.DefaultKaptchakaptcha.textproducer.implThe text producer.com.google.code.kaptcha.text.impl.DefaultTextCreatorkaptcha.textproducer.char.stringThe characters that will create the kaptcha.abcde2345678gfynmnpwxkaptcha.textproducer.char.lengthThe number of characters to display.5kaptcha.textproducer.font.namesA list of comma separated font names.Arial, Courierkaptcha.textproducer.font.sizeThe size of the font to use.40px.kaptcha.textproducer.font.colorThe color to use for the font. Legal values are r,g,b.blackkaptcha.noise.implThe noise producer.com.google.code.kaptcha.impl.DefaultNoisekaptcha.noise.colorThe noise color. Legal values are r,g,b.blackkaptcha.obscurificator.implThe obscurificator implementation.com.google.code.kaptcha.impl.WaterRipplekaptcha.background.implThe background implementation.com.google.code.kaptcha.impl.DefaultBackgroundkaptcha.background.clear.fromStarting background color. Legal values are r,g,b.light greykaptcha.background.clear.toEnding background color. Legal values are r,g,b.whitekaptcha.word.implThe word renderer implementation.com.google.code.kaptcha.text.impl.DefaultWordRendererkaptcha.session.keyThe 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_KEYkaptcha.session.dateThe date the kaptcha is generated is put into the HttpSession. This is the key value for that item in the session.KAPTCHA_SESSION_DATE