Spring boot如何集成kaptcha并生成验证码

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

package com.dream.road.config;

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 producer() {
    Properties properties = new Properties();
    // 设置边框
    properties.put("kaptcha.border", "yes");
    // 设置边框颜色
    properties.put("kaptcha.border.color", "105,179,90");
    // 设置字体颜色
    properties.put("kaptcha.textproducer.font.color", "black");
    // 设置图片宽度
    properties.put("kaptcha.image.width", "160");
    // 设置图片高度
    properties.put("kaptcha.image.height", "50");
    //设置字体尺寸
    properties.put("kaptcha.textproducer.font.size", "30");
    // 设置验证码长度
    properties.put("kaptcha.textproducer.char.length", "5");
    // 设置字体
    properties.put("kaptcha.textproducer.font.names", "宋体,楷体,黑体");

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

package com.dream.road.controller;

import com.google.code.kaptcha.Constants;
import com.google.code.kaptcha.Producer;
import org.apache.tomcat.util.http.fileupload.IOUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.image.BufferedImage;
import java.io.IOException;

@RestController
public class LoginController {

  @Autowired
  private Producer producer;

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

    // 生成文字验证码
    String text = producer.createText();
    // 生成图片验证码
    BufferedImage image = producer.createImage(text);
    // 保存到验证码到 session
    request.getSession().setAttribute(Constants.KAPTCHA_SESSION_KEY, text);

    ServletOutputStream out = response.getOutputStream();
    ImageIO.write(image, "jpg", out);
    IOUtils.closeQuietly(out);
  }

}