ApplicationContext、BeanFactory之间的区别：
https://blog.csdn.net/weixin_44550490/article/details/100692763
BeanFactory、FactoryBean之间的区别：
https://www.cnblogs.com/aspirant/p/9082858.html
Spring是如何实现懒加载的
https://blog.csdn.net/yerenyuan_pku/article/details/110291379
Spring Bean是线程安全的吗？
https://www.cnblogs.com/myseries/p/11729800.html
Spring bean配置的三种方式（XML、注解、Java类）
https://blog.csdn.net/echizao1839/article/details/88063013
