引入依赖:
<!--验证码-->
<dependency>
<groupId>com.github.penggle</groupId>
<artifactId>kaptcha</artifactId>
<version>2.3.2</version>
</dependency>
web.xml文件配置
当前端页面调用图片验证码的url时,就会路由到/Kaptcha
<!--验证码-->
<servlet>
<servlet-name>Kaptcha</servlet-name>
<servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class>
<!--是否有边框-->
<init-param>
<param-name>kaptcha.border</param-name>
<param-value>no</param-value>
</init-param>
<!--字体颜色-->
<init-param>
<param-name>kaptcha.textproducer.font.color</param-name>
<param-value>red</param-value>
</init-param>
<!--字体大小-->
<init-param>
<param-name>kaptcha.textproducer.font.size</param-name>
<param-value>43</param-value>
</init-param>
<!--图片宽度-->
<init-param>
<param-name>kaptcha.image.width</param-name>
<param-value>135</param-value>
</init-param>
<!--高度-->
<init-param>
<param-name>kaptcha.image.height</param-name>
<param-value>50</param-value>
</init-param>
<!--使用哪些字符生成验证码-->
<init-param>
<param-name>kaptcha.textproducer.char.string</param-name>
<param-value>ACDEFHKPRSTWX345679</param-value>
</init-param>
<!--干扰线颜色-->
<init-param>
<param-name>kaptcha.noise.color</param-name>
<param-value>black</param-value>
</init-param>
<!--验证码字符个数-->
<init-param>
<param-name>kaptcha.textproducer.char.length</param-name>
<param-value>4</param-value>
</init-param>
<!--字体-》宋体-->
<init-param>
<param-name>kaptcha.textproducer.font.names</param-name>
<param-value>Arial</param-value>
</init-param>
</servlet>
<!--指定路由规则-->
<servlet-mapping>
<servlet-name>Kaptcha</servlet-name>
<url-pattern>/Kaptcha</url-pattern>
</servlet-mapping>
前端代码:
html:
可以看到,实际上前端代码并没有什么变化。
<div class="item-content">
<div class="item-inner">
<div class="item-title label">验证码</div>
<input type="text" id="j_kaptcha" placeholder="验证码">
<div class="item-input">
<img id="kaptcha_img" alt="点击更换" placeholder="验证码" onclick="changeVerifyCode(this)" src="../Kaptcha"/>
</div>
</div>
</div>
js:
需要注意的是,在我们点击 onclick事件时,如果url不发生变化,那么请求是不是传送到后端的,因此我们可以采用加随机数和日期的方式。
function changeVerifyCode(img) {
//url需要发生变换
img.src="../Kaptcha?"+Math.floor(Math.random()*100);
}
后端校验代码逻辑:
package com.util;
import com.google.code.kaptcha.Constants;
import javax.servlet.http.HttpServletRequest;
/**
* @Created with IntelliJ IDEA
* @Description: 判断前端输入的验证码是否正确
* @Package: com.util
* @author: FLy-Fly-Zhang
* @Date: 2020/2/8
* @Time: 14:34
*/
public class CodeUtil {
public static boolean checkVerifyCode(HttpServletRequest request){
//会话信息中存在的验证码
String verifyCodeExpected=(String)request.getSession()
.getAttribute(Constants.KAPTCHA_SESSION_KEY);
//前端输入的验证码
String verifyCodeActual=HttpServletRequestUtil
.getString(request,"verifyCodeActual");
if(verifyCodeActual==null||!verifyCodeActual.equals(verifyCodeExpected))
return false;
return true;
}
}