本文为大家分享了kaptcha验证码的使用方法，供大家参考，具体内容如下

1.首先在pom.xml文件中导入Maven依赖

<dependency> <groupId>com.github.penggle</groupId> <artifactId>kaptcha</artifactId> <version>2.3.2</version></dependency>

2.在web.xml文件中配置一个servlet

<servlet> <!-- 生成图片的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> <!-- 图片宽度 --> <init-param> <param-name>kaptcha.image.width</param-name> <param-value>135</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> <!-- 图片高度 --> <init-param> <param-name>kaptcha.image.height</param-name> <param-value>50</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> <!-- 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> <!-- 使用哪些字体 --> <init-param> <param-name>kaptcha.textproducer.font.names</param-name> <param-value>Arial</param-value> </init-param> </servlet> <!-- 映射的url --> <servlet-mapping> <servlet-name>Kaptcha</servlet-name> <url-pattern>/Kaptcha</url-pattern> </servlet-mapping>

3.页面代码如下

<div class="item-inner"> <label for="j_captcha" class="item-title label">验证码</label> <input id="j_captcha" name="j_captcha" type="text" class="form-control in" placeholder="验证码" /> <div class="item-input"> <img id="captcha_img" alt="点击更换" title="点击更换" onclick="changeVerifyCode(this)" src="../Kaptcha" /> </div></div>

向后端提交数据

var verifyCodeActual = $('#j_captcha').val(); if (!verifyCodeActual) { $.toast('请输入验证码！'); return; } formData.append("verifyCodeActual", verifyCodeActual);

4.js交互

function changeVerifyCode(img) { img.src = "../Kaptcha?" + Math.floor(Math.random() * 100);}

5.后端验证

import javax.servlet.http.HttpServletRequest;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.equalsIgnoreCase(verifyCodeExpected)) { return false; } return true; }}import javax.servlet.http.HttpServletRequest;public class HttpServletRequestUtil { public static int getInt(HttpServletRequest request, String name) { try { return Integer.decode(request.getParameter(name)); } catch (Exception e) { return -1; } } public static long getLong(HttpServletRequest request, String name) { try { return Long.valueOf(request.getParameter(name)); } catch (Exception e) { return -1; } } public static Double getDouble(HttpServletRequest request, String name) { try { return Double.valueOf(request.getParameter(name)); } catch (Exception e) { return -1d; } } public static Boolean getBoolean(HttpServletRequest request, String name) { try { return Boolean.valueOf(request.getParameter(name)); } catch (Exception e) { return false; } } public static String getString(HttpServletRequest request, String name) { try { String result = request.getParameter(name); if (result != null) { result = result.trim(); } if ("".equals(result)) result = null; return result; } catch (Exception e) { return null; } }}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。