跨域扫盲

Reference：

• https://zhuanlan.zhihu.com/p/121048298

• http://www.garyqiang.com/post/qian-duan/kua-yu-wen-ti-shi-zhan

• http://wangwenming.github.io/misc/2017/02/07/Cookie%E6%89%AB%E7%9B%B2%E8%B4%B4.html

• 参考工程：jx-decorate-loan/com.huizhaofang.jx.core.common.config.JxCorsConfiguration