首先springboot跨域设置:
https://www.baeldung.com/spring-cors
http://www.ruanyifeng.com/blog/2016/04/cors.html
https://blog.csdn.net/yin138/article/details/79274604
https://developer.mozilla.org/zh-CN/docs/Web/HTTP/Access_control_CORS
跨域出现问题:
1. 跨域出现问题