话不多少，直接上干货！

开发环境：

IDEA : IntelliJ IDEA 2020.3.3 x64

springboot:2.0.3

配置步骤

导入jar包

      pom中导入kaptcha相关依赖

<dependency>
   <groupId>com.github.axet</groupId>
   <artifactId>kaptcha</artifactId>
   <version>0.0.9</version>
</dependency>

编写kaptcha配置类

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
    public DefaultKaptcha producer() {
        Properties properties = new Properties();
        properties.put("kaptcha.border", "no");
        properties.put("kaptcha.textproducer.font.color", "black");
        properties.put("kaptcha.textproducer.char.space", "5");
        Config config = new Config(properties);
        DefaultKaptcha defaultKaptcha = new DefaultKaptcha();
        defaultKaptcha.setConfig(config);
        return defaultKaptcha;
    }
}

在controller中使用：

/**
 * 验证码
 */

  @Autowired
  private Producer producer;

@GetMapping("captcha.jpg")
public void getKaptcha(HttpServletRequest request, HttpServletResponse response) throws IOException {
    //设置响应头
    response.setHeader("Cache-Control", "no-store, no-cache");
    response.setContentType("image/jpeg");

    //生成文字验证码
    String text = producer.createText();
    //创建验证码图片
    BufferedImage image = producer.createImage(text);
    ServletOutputStream out = response.getOutputStream();
    ImageIO.write(image, "jpg", out);
    IOUtils.closeQuietly(out);
  }
}

配合前端使用，可以完美呈现出验证码信息