java springboot实现验证码参考网址

https://www.cnblogs.com/softidea/p/6914279.html

https://blog.csdn.net/u013435893/article/details/79617872

https://liuyanzhao.com/8104.html

https://liuyanzhao.com/8115.html

https://www.jianshu.com/p/6522258a1d43

http://www.imooc.com/article/252934

https://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&rsv_idx=1&tn=baidu&wd=spring%20security%20%E9%AA%8C%E8%AF%81%E7%A0%81&oq=WebSecurity%2526lt%253Bonfig&rsv_pq=e26c066b0000c97f&rsv_t=7a43FFU24kgZHOwFKATwkzVT8pFgMzssBuyQuNZUkZ1xRBnCUUA5h596buI&rqlang=cn&rsv_enter=1&rsv_sug3=5&rsv_sug1=4&rsv_sug7=100&rsv_n=2&bs=WebSecurityConfig

https://ask.csdn.net/questions/337776?ref=myrecommend

https://www.cnblogs.com/deviltofree/p/10044046.html