缓存策略通用接口及其实现，包括常用的:
- Cache Aside 旁路缓存模式
- Read/Write Through 读穿/写穿模式
- Write Back 写回策略
read from cache hit return date miss read from DB, write to cache
write to DB delete cache
read from cache hit return date else read from DB and write cache return value
check isExist from cache
if exist Update cache and update DB else write cache and write DB or write DB
read cache hit write cache and mark cache isDirty
miss
if isDirty write DB
read DB
write cache
mark cache isDirty
read cache hit return if isDirty write DB read cache mark no dirty