验证码之Kaptcha

说明：以下内容是在ssm框架基础上实现的，请自行搭建好框架

1、下载jar包

<!-- 验证码相关 -->
<!-- https://mvnrepository.com/artifact/com.github.penggle/kaptcha -->
<dependency>
	<groupId>com.github.penggle</groupId>
	<artifactId>kaptcha</artifactId>
	<version>2.3.2</version>
</dependency>

2、在web.xml配置

<!-- 验证码相关 -->
<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>
	<!-- 图片的宽度 -->
	<init-param>
		<param-name>kaptcha.image.width</param-name>
		<param-value>135</param-value>
	</init-param>
	<!-- 图片的高度 -->
	<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>
	<!-- 干扰线的颜色-->
	<init-param>
		<param-name>kaptcha.noise.color</param-name>
		<param-value>black</param-value>
	</init-param>
	<!-- 字符个数-->
	<init-param>
		<param-name>kaptcha.textproducer.char.length</param-name>
		<param-value>4</param-value>
	</init-param>
	<!-- 字体-->
	<init-param>
		<param-name>kaptcha.textproducer.font.names</param-name>
		<param-value>Arial</param-value>
	</init-param>
</servlet>
<servlet-mapping>
	<servlet-name>Kaptcha</servlet-name>
	<url-pattern>/Kaptcha</url-pattern>
</servlet-mapping>

3、在页面中使用验证码

<li>
   <div class="item-content">
      <div class="item-media"><i class="icon icon-form-name"></i></div>
      <div class="item-inner">
	     <div class="item-title label">验证码</div>
	     <input type="text" placeholder="验证码">
	     <div class="item-input">
	       <img id="yzm_img" title="验证码" alt="验证码" src="../Kaptcha" onclick="change_yzm(this)">
	     </div>
	 </div>
    </div>
 </li>

4、效果图

5、更换验证码

定义改变验证码的方法

<script type="text/javascript">
   function change_yzm(img){
		img.src="../Kaptcha?"+Math.floor(Math.random()*100);
	}
   </script>

6、校验验证码的方法

/**
 * 校验验证码是否正确
 * @author Mr.Feng
 *
 */
public class CodeUtil {
	public static boolean checkVerifyCode(HttpServletRequest request) {
		String verifyCodeExpected = (String)request.getSession().getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
		String verifyCOdeActual = HttpServletRequestUtil.getString(request,"verifyCodeActual");
		
		if(verifyCOdeActual==null|| !verifyCOdeActual.equals(verifyCodeExpected)) {
			return false;
		}
		return true;
	}

}