<!-- 验证码 -->

        <dependency>

            <groupId>com.github.penggle</groupId>

            <artifactId>kaptcha</artifactId>

            <version>2.3.2</version>

        </dependency>

package com.demo.common;

import java.util.Properties;

import org.springframework.context.annotation.Bean;

import org.springframework.stereotype.Component;

import com.google.code.kaptcha.impl.DefaultKaptcha;

import com.google.code.kaptcha.util.Config;

@Component

public class KaptchaConfig {

    @Bean

    public DefaultKaptcha getDefaultKaptcha() {

        com.google.code.kaptcha.impl.DefaultKaptcha defaultKaptcha = new com.google.code.kaptcha.impl.DefaultKaptcha();

        Properties properties = new Properties();

        // 图片边框

        properties.setProperty("kaptcha.border", "yes");

        // 边框颜色

        properties.setProperty("kaptcha.border.color", "105,179,90");

        // 字体颜色

        properties.setProperty("kaptcha.textproducer.font.color", "red");

        // 图片宽

        properties.setProperty("kaptcha.image.width", "110");

        // 图片高

        properties.setProperty("kaptcha.image.height", "40");

        // 字体大小

        properties.setProperty("kaptcha.textproducer.font.size", "30");

        // session key

        properties.setProperty("kaptcha.session.key", "code");

        // 验证码长度

        properties.setProperty("kaptcha.textproducer.char.length", "4");

        // 字体

        properties.setProperty("kaptcha.textproducer.font.names", "宋体,楷体,微软雅黑");

        Config config = new Config(properties);

        defaultKaptcha.setConfig(config);

        return defaultKaptcha;

    }

}

package com.demo.controller;

import java.awt.image.BufferedImage;

import java.io.IOException;

import javax.imageio.ImageIO;

import javax.servlet.ServletOutputStream;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.servlet.ModelAndView;

import com.google.code.kaptcha.Constants;

import com.google.code.kaptcha.Producer;

@Controller

@RequestMapping(value = "/captcha")

public class CaptchaController {

    private Producer captchaProducer = null;

    @Autowired

    public void setCaptchaProducer(Producer captchaProducer) {

        this.captchaProducer = captchaProducer;

    }

    /**

     *

     * 获取验证码图片

     *

     * @param request

     * @param response

     * @return

     * @throws IOException

     */

    @RequestMapping("getCaptchaCode")

    public ModelAndView getCaptchaCode(HttpServletRequest request, HttpServletResponse response) throws IOException {

        HttpSession session = request.getSession();

        response.setDateHeader("Expires", 0);

        response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");

        response.addHeader("Cache-Control", "post-check=0, pre-check=0");

        response.setHeader("Pragma", "no-cache");

        response.setContentType("image/jpeg");

        // 生成验证码文本

        String capText = captchaProducer.createText();

        session.setAttribute(Constants.KAPTCHA_SESSION_KEY, capText);

        // 利用生成的字符串构建图片

        BufferedImage bi = captchaProducer.createImage(capText);

        ServletOutputStream out = response.getOutputStream();

        ImageIO.write(bi, "jpg", out);

        try {

            out.flush();

        } finally {

            out.close();

        }

        return null;

    }

}

　　　　　　　　　　<form class="registerform" id="form1">

                    <div class="fm-item">

                        <label for="logonId" class="form-label">登陆账号：</label>

                        <input type="text" maxlength="100" id="username" name="username" class="i-text"/>

                        <div class="ui-form-explain"></div>

                    </div>

                    <div class="fm-item">

                        <label for="logonId" class="form-label">登陆密码：</label>

                        <input type="password" maxlength="100" id="password" name="password" class="i-text"/>

                        <div class="ui-form-explain"></div>

                    </div>

                    <div class="fm-item pos-r">

                        <label for="logonId" class="form-label">验证码</label>

                        <input type="text" maxlength="100" id="yzm" name="yzm" class="i-text yzm"/>

                        <div class="ui-form-explain">

                            <img id="captchaImg" alt="" th:src="@{/captcha/getCaptchaCode}" class="yzm-img" style="width: 100px;height: 40px;line-height:40px;"/>

                        </div>

                    </div>

                    <div class="fm-item">

                        <label for="logonId" class="form-label"></label>

                        <input type="button" value="" tabindex="4" id="submit" class="btn-login"/>

                        <div class="ui-form-explain"></div>

                    </div>

                </form>

//获取新验证码

$('#captchaImg').click(function() {

     $(this).attr('src', '/captcha/getCaptchaCode.jpg');

});