<meta content="no-referrer" name="referrer"/>

maven依赖

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

kaptcha配置

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;


@Configuration
public class KaptchaConfig {

    @Bean
    public DefaultKaptcha getDefaultKaptcha() {
        DefaultKaptcha kaptcha = new DefaultKaptcha();
        Properties properties = new Properties();
        // 图片边框
        properties.setProperty("kaptcha.border", "no");
        // 字体颜色
        properties.setProperty("kaptcha.textproducer.font.color", "black");
        // 字体间距
        properties.setProperty("kaptcha.textproducer.char.space", "5");
        // 图片宽
        properties.setProperty("kaptcha.image.width", "120");
        // 图片高
        properties.setProperty("kaptcha.image.height", "50");
        // 验证码长度
        properties.setProperty("kaptcha.textproducer.char.length", "4");
        // 噪点生成对象
        properties.setProperty("kaptcha.noise.impl", "com.google.code.kaptcha.impl.NoNoise");

        // 边框颜色
         properties.setProperty("kaptcha.border.color", "105,179,55");
        // 字体大小
        // properties.setProperty("kaptcha.textproducer.font.size", "30");
        // session key
        // properties.setProperty("kaptcha.session.key", "code");
        // 字体
        // properties.setProperty("kaptcha.textproducer.font.names", "宋体,楷体,微软雅黑");

        Config config = new Config(properties);
        kaptcha.setConfig(config);
        return kaptcha;
    }

}

生成验证码

在这里我们把正确的验证码放到redis中，便于后续的验证

import com.google.code.kaptcha.impl.DefaultKaptcha;
import com.me.flashsale.common.Constants;
import com.me.flashsale.domain.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.util.concurrent.TimeUnit;

/**
 *   验证码的生成
 */
@Controller
@Slf4j
@RequestMapping("/kaptcha")
public class KaptchaController {

    /**
     * 1、验证码工具
     */
    @Autowired
    private DefaultKaptcha kaptcha;
    @Autowired
    private StringRedisTemplate redisTemplate;

    /**
     * 生成验证码
     * @param httpServletResponse
     * @param user
     * @param goodsId
     * @throws Exception
     */
    @RequestMapping("/jpg")
    public void getKaptcha(HttpServletResponse httpServletResponse, User user, long goodsId)
            throws Exception {
        byte[] captchaChallengeAsJpeg;
        ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
        try {
            // 生产验证码字符串并保存到redis中
            String rightCode = kaptcha.createText();
            log.info("rightCode:{}", rightCode);
            redisTemplate.opsForValue().set(Constants.Cache.KAPTCHA_REDIS_PREFIX+user.getId()+"_goods"+goodsId, rightCode,
                    Constants.Cache.KAPTCHA_EXPIRE_TIME, TimeUnit.SECONDS);

            // 使用生产的验证码字符串返回一个BufferedImage对象并转为byte写入到byte数组中
            BufferedImage challenge = kaptcha.createImage(rightCode);
            ImageIO.write(challenge, "jpg", jpegOutputStream);
        } catch (IllegalArgumentException e) {
            httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }
        // 定义response输出类型为image/jpeg类型，使用response输出流输出图片的byte数组
        captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
        httpServletResponse.setHeader("Cache-Control", "no-store");
        httpServletResponse.setHeader("Pragma", "no-cache");
        httpServletResponse.setDateHeader("Expires", 0);
        httpServletResponse.setContentType("image/jpeg");
        ServletOutputStream responseOutputStream = httpServletResponse.getOutputStream();
        responseOutputStream.write(captchaChallengeAsJpeg);
        responseOutputStream.flush();
        responseOutputStream.close();
    }

}

前端使用

使用的方式很简单，直接img标签的src属性调用controller的接口即可

验证逻辑

    @Autowired
    private StringRedisTemplate redisTemplate;
    /**
     * 校对验证码
     * @param user
     * @param goodsId
     * @param tryCode
     * @return
     */
    public Boolean imgVerifyCode(User user, long goodsId, String tryCode) {
        String rightCode = redisTemplate.opsForValue().get(Constants.Cache.KAPTCHA_REDIS_PREFIX + user.getId()
                +"_goods"+ goodsId);
        log.info("rightCode={}, tryCode={}", rightCode, tryCode);
        return tryCode.equals(rightCode);
    }