Springboot使用kaptcha生成验证码

        <dependency>
            <groupId>com.youkol.support.kaptcha</groupId>
            <artifactId>kaptcha</artifactId>
            <version>2.3.2</version>
        </dependency>

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 defaultKaptcha=new DefaultKaptcha();
        Properties properties=new Properties();
        properties.setProperty("kaptcha.border", "no");
        properties.setProperty("kaptcha.border.color", "34,114,200");
        properties.setProperty("kaptcha.image.width", "200");
        properties.setProperty("kaptcha.image.height", "50");
        //properties.setProperty("kaptcha.textproducer.char.string", "0123456789");
        properties.setProperty("kaptcha.textproducer.char.length", "4");
        properties.setProperty("kaptcha.textproducer.font.names", "Arial,Arial Narrow,Serif,Helvetica,Tahoma,Times New Roman,Verdana");
        properties.setProperty("kaptcha.textproducer.font.size", "38");

        properties.setProperty("kaptcha.background.clear.from", "white");
        properties.setProperty("kaptcha.background.clear.to", "white");

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

}

import com.google.code.kaptcha.impl.DefaultKaptcha;
import jakarta.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.codec.binary.Base64;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.TimeUnit;

@Slf4j
@Service
public class CaptchaServiceImpl implements CaptchaService {

    @Resource
    RedisTemplate<String, String> redis0Template;

    @Resource
    DefaultKaptcha defaultKaptcha;

    private static final String captchaPrefix = "captcha:";

    @Override
    public Map<String, String> captcha() {
        String kaptchaText = defaultKaptcha.createText();
        BufferedImage image = defaultKaptcha.createImage(kaptchaText);

        String base64Code = "";
        try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {
            ImageIO.write(image, "jpg", outputStream);
            base64Code = Base64.encodeBase64String(outputStream.toByteArray());
        } catch (Exception e) {
            log.error("error when generate captcha", e);
        }

        //uuid; 唯一标识code
        //code; 验证码图片的Base64串
        Map<String, String> kaptchaVoMap = new HashMap<>();
        String uuid = UUID.randomUUID().toString();
        kaptchaVoMap.put("uuid", uuid);
        kaptchaVoMap.put("code", "data:image/png;base64," + base64Code);
        redis0Template.opsForValue().set(captchaPrefix + uuid, kaptchaText, 5, TimeUnit.MINUTES);
        return kaptchaVoMap;
    }

    @Override
    public boolean valid(String uuid, String code) {
        String kaptchaText = redis0Template.opsForValue().get(captchaPrefix + uuid);
        if (kaptchaText != null && kaptchaText.equalsIgnoreCase(code)) {
            redis0Template.delete(captchaPrefix + uuid);
            return true;
        }
        return false;
    }
}