在pom文件中添加依赖：
<dependency>
<groupId>com.github.penggle</groupId>
<artifactId>kaptcha</artifactId>
<version>2.3.2</version>
<exclusions>
<exclusion>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
</exclusion>
</exclusions>
</dependency>
在web.xml中配置一个servlet：
<!--利用servlet生成验证码-->
<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>
<!-- 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>
<!-- 字体 -->
<init-param>
<param-name>kaptcha.textproducer.font.names</param-name>
<param-value>Arial</param-value>
</init-param>
<!-- Session的key -->
<init-param>
<param-name>kaptcha.session.key</param-name>
<param-value>captcha</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>Kaptcha</servlet-name>
<url-pattern>/captcha</url-pattern>
</servlet-mapping>
建立Controller：
1 package com.yas.controller;
2
3 import org.springframework.stereotype.Controller;
4 import org.springframework.web.bind.annotation.RequestMapping;
5
6 import javax.servlet.http.HttpSession;
7
8 @Controller
9 @RequestMapping("/captcha")
10 public class CaptchaController {
11
12 @RequestMapping("/test1")
13 public String test1(String captcha, HttpSession session) {
14 String realCaptcha = (String) session.getAttribute("captcha");
15 if (realCaptcha.equals(captcha)) {
16 return "hello";
17 }
18 return "error1";
19 }
20 }
建立测试页面captcha.jsp：
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
<script>
function refresh(){
var img = document.getElementById("cap");
img.src = "${pageContext.request.contextPath}/captcha?"+new Date().getTime();
}
</script>
</head>
<body>
<form action="${pageContext.request.contextPath}/captcha/test1">
<img id="cap" src="${pageContext.request.contextPath}/captcha" onclick="refresh()">
<input type="text" name="captcha">
<br>
<input type="submit" value="提交">
</form>
</body>
</html>