https://www.cnblogs.com/hafiz/p/10330329.html
url
元数据自定义注解https://blog.csdn.net/u013045971/article/details/53433874java
IDEA使用文档
https://www.w3cschool.cn/intellij_idea_doc/intellij_idea_doc-3xqd2df6.html
idea
https://jingyan.baidu.com/article/29697b9163ac7dab20de3cbf.html
单例模式学习
https://www.cnblogs.com/zhaoyan001/p/6365064.html
枚举的使用
https://www.cnblogs.com/panxuejun/p/7246283.html
stataic
https://www.cnblogs.com/dolphin0520/p/3799052.html
https://www.cnblogs.com/chenssy/p/3386721.html
json 常见几种json处理库Gson，FastJson，Jackson，Json-lib。
https://www.cnblogs.com/xiaochongchong/p/5284441.html
https://www.cnblogs.com/tech-bird/p/3588430.html
https://www.cnblogs.com/duandians/p/9836253.html
https://blog.csdn.net/zl1zl2zl3/article/details/85536515