知识点--实际开发中软引用或弱引用的使用场景

https://blog.csdn.net/lixq05/article/details/77746168

https://www.jianshu.com/p/a7aaaf1bd7be

https://www.cnblogs.com/yw-ah/p/5830458.html

https://www.cnblogs.com/dolphin0520/p/3784171.html