一、配置Maven坐标
<!-- https://mvnrepository.com/artifact/com.github.penggle/kaptcha -->
<dependency>
<groupId>com.github.penggle</groupId>
<artifactId>kaptcha</artifactId>
<version>2.3.2</version>
</dependency>
二、配置Web.xml
<!-- 配置验证码插件servlet类 -->
<servlet>
<servlet-name>kaptcha</servlet-name>
<servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class>
<!-- 给验证码插件servlet类配置参数 -->
<!-- 边框设置 yes no -->
<init-param>
<param-name>kaptcha.border</param-name>
<param-value>no</param-value>
</init-param>
<!-- 边框颜色 颜色名称 例如：red blue black等 也可以是 RGB：105,179,90 -->
<init-param>
<param-name>kaptcha.border.color</param-name>
<param-value>red</param-value>
</init-param>
<!-- 边框宽度 -->
<init-param>
<param-name>kaptcha.border.thickness</param-name>
<param-value>5</param-value>
</init-param>
<!-- 产生验证码的字符源头 兼容中文的 -->
<init-param>
<param-name>kaptcha.textproducer.char.string</param-name>
<param-value>1234567890产生验证码的字符源头</param-value>
</init-param>
<!-- 生成结果的字符个数 -->
<init-param>
<param-name>kaptcha.textproducer.char.length</param-name>
<param-value>5</param-value>
</init-param>
<!-- 生成结果的字符字体 -->
<init-param>
<param-name>kaptcha.textproducer.font.names</param-name>
<param-value>微软雅黑,宋体,楷体</param-value>
</init-param>
<!-- 生成结果的字符大小 -->
<init-param>
<param-name>kaptcha.textproducer.font.size</param-name>
<param-value>40</param-value>
</init-param>
<!-- 生成结果的字符 颜色 -->
<init-param>
<param-name>kaptcha.textproducer.font.color</param-name>
<param-value>blue</param-value>
</init-param>
<!-- 生成结果的字符 字间距 -->
<init-param>
<param-name>kaptcha.textproducer.char.space</param-name>
<param-value>2</param-value>
</init-param>
<!-- 干扰线 生成器 -->
<init-param>
<param-name>kaptcha.noise.impl</param-name>
<param-value>com.google.code.kaptcha.impl.DefaultNoise</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>
<!-- 干扰线 背景渐变颜色 从左侧向右渐变 -->
<init-param>
<param-name>kaptcha.background.clear.from</param-name>
<param-value>green</param-value>
</init-param>
<!-- 干扰线 背景渐变颜色 从右侧向左渐变 -->
<init-param>
<param-name>kaptcha.background.clear.to</param-name>
<param-value>yellow</param-value>
</init-param>
<!-- 验证码图片宽度 -->
<init-param>
<param-name>kaptcha.image.width</param-name>
<param-value>200</param-value>
</init-param>
<!-- 验证码图片高度 -->
<init-param>
<param-name>kaptcha.image.height</param-name>
<param-value>50</param-value>
</init-param>
</servlet>
<!-- 验证码请求名 映射
//从session中取服务器中的验证码
String kaptchaServer = (String)request.getSession().getAttribute
(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
-->
<servlet-mapping>
<servlet-name>kaptcha</servlet-name>
<url-pattern>/mykaptcha</url-pattern>
</servlet-mapping>
三、编写jsp页面
四、验证
五、错误解决方案
严重: Servlet.service() for servlet jsp threw exception
java.lang.LinkageError: loader constraint violation: loader (instance of org/apache/jasper/servlet/JasperLoader) previously initiated loading for a different type with name "javax/servlet/http/HttpServletRequest"
<!-- 添加Servlet -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
替换为
<!-- 添加Servlet -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
