java知识考点 2020-03-03 本文已影响0人 迷糊银儿 https://note.youdao.com/ynoteshare1/index.html?id=bee15cfa51a0292137fc83e3c315a0f4&type=note 单例的7种模式：https://note.youdao.com/ynoteshare1/index.html?id=5d0ad321a1990c7f608ad5794c8203ec&type=note
