JAVA整合kaptcha生成验证码

引入maven

<!--图片验证码-->
        <dependency>
            <groupId>com.github.penggle</groupId>
            <artifactId>kaptcha</artifactId>
            <version>2.3.2</version>
            <exclusions>
                <exclusion>
                    <artifactId>javax.servlet-api</artifactId>
                    <groupId>javax.servlet</groupId>
                </exclusion>
            </exclusions>
        </dependency>

验证码配置类

KaptchaConfig.java

package com.test.cms.kaptcha;

import com.google.code.kaptcha.impl.DefaultKaptcha;
import com.google.code.kaptcha.util.Config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.Properties;

/**
 * 验证码配置
 */
@Configuration
public class KaptchaConfig {


    
    @Bean(name = "captchaProducer")
    public DefaultKaptcha getKaptchaBean() {
        Properties properties = new Properties();
        //图片边框
        properties.setProperty("kaptcha.border", "no");
        //文本集合，验证码值从此集合中获取
        properties.setProperty("kaptcha.textproducer.char.string", "ABCDEGHJKLMNRSTUWXY23456789");
        //字体颜色
        properties.setProperty("kaptcha.textproducer.font.color", "0,84,144");
        //干扰颜色
        properties.setProperty("kaptcha.noise.color", "0,84,144");
        //字体大小
        properties.setProperty("kaptcha.textproducer.font.size", "30");
        //背景颜色渐变，开始颜色
        properties.setProperty("kaptcha.background.clear.from", "247,255,234");
        //背景颜色渐变，结束颜色
        properties.setProperty("kaptcha.background.clear.to", "247,255,234");
        //图片宽
        properties.setProperty("kaptcha.image.width", "125");
        //图片高
        properties.setProperty("kaptcha.image.height", "35");
        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", "Arial, Courier");
        Config config = new Config(properties);
        DefaultKaptcha defaultKaptcha = new DefaultKaptcha();
        defaultKaptcha.setConfig(config);
        return defaultKaptcha;
    }
}

控制器类

KaptchaController.java    

package com.test.cms.kaptcha;

import com.google.code.kaptcha.Producer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import sun.misc.BASE64Encoder;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.util.HashMap;
import java.util.Map;

@RestController
public class KaptchaController {

    /**
     * 加载图形验证码
     */
    @GetMapping("/kaptcha")
    public String getKaptchaImage(HttpServletRequest request, HttpServletResponse response) throws Exception {
        response.setDateHeader("Expires", 0);
        // 设置浏览器渲染不做本地缓存
        response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
        // Set IE extended HTTP/1.1 no-cache headers (use addHeader).
        response.addHeader("Cache-Control", "post-check=0, pre-check=0");
        response.setHeader("Content-Security-Policy", "none");
        // 设置浏览器渲染不读取浏览器缓存
        response.setHeader("Pragma", "no-cache");

        String originHeader = request.getHeader("Origin");
        // 这个限定来自自身服务端域名
        /*if (originHeader != null && (originHeader.contains(request.getServerName()))) {
            response.setHeader("Access-Control-Allow-Origin", originHeader);
        } else {
            response.setHeader("Access-Control-Allow-Origin", request.getServerName());
        }*/
        // 设置浏览器渲染图片类型
        response.setContentType("image/jpeg");
        // 生成验证码内容
        String capText = captchaProducer.createText();

        String sessionId = request.getSession().getId();

        System.out.println(sessionId + "," + capText);

        /**
         *这里将sessionId作为key存入redis中，用于后面的验证码验证,可以设置失效时间
         * springboot整合redis可以参考 https://www.cnblogs.com/pxblog/p/12980634.html
         */
        //redisService.set(Constants.KAPTCHA_SESSION_KEY+sessionId, capText);

        //生成图片
        BufferedImage bi = captchaProducer.createImage(capText);
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        ImageIO.write(bi, "jpg", outputStream);

        Map<String, Object> map = new HashMap<String, Object>(2);

        //转为base64
        String img=imageToBase64ByByte(outputStream.toByteArray());

        map.put("img", img);
        //sessionId 主要用于验证验证码使用
        map.put("sessionId", sessionId);

        try {
            outputStream.flush();
        }finally {
            outputStream.close();
        }
        //这里将map返回到前台,此处简单demo
        return img+","+sessionId;
    }


    public static String imageToBase64ByByte(byte[] data) {
        BASE64Encoder encoder = new BASE64Encoder();
        return encoder.encode(data);
    }


    /**
     * 验证验证码是否正确
     * @param code  前台填写的验证码
     * @param sessionId  生成验证码时返回的sessionId
     * @return
     */
    @GetMapping("/valid")
    public Boolean valid(String code,String sessionId) {

        String verifyCode ="这里从redis中取出原本的验证码进行判断：redisService.get(Constants.KAPTCHA_SESSION_KEY+sessionId)";
        System.out.println(verifyCode);
        return verifyCode.equalsIgnoreCase(code);
    }


    @Autowired
    private Producer captchaProducer;


}

页面调用

<div class="letter pointer" id="getCapatchImg"><img id="capatchImg"  onclick="genCapatch()" /></div>

// 图形验证码

            var sessionId="";
            $(function () {
                $("#getCapatchImg").on("click", function (event) {
                            genCapatch();
                    });
            });
            function genCapatch() {
                    $.ajax({
                            url: "/kaptcha",
                            data: {},
                            success: function (result) {
                                    document.getElementById('capatchImg').src = "data:image/png;base64," + result.data.img;
                        sessionId=result.data.sessionId
                            }
                    });
            }