Spring的生命周期大致分为：创建 -> 属性填充 -> 初始化bean -> 使用 -> 销毁 几个核心阶段。我们先来简单了解一下这些阶段所做的事情：
What makes students from elite schools special?
Every accomplished person I know had a mentor. Usually their parents, sometimes teachers or friends. Kids don't just start thinking "I want to go to MIT in 4 years, so I'd better start doing math contests, and getting research internships, and self-studying AP classes so I can take tests my school doesn't offer." Someone had to tell them those things existed, and that they could actually do them. Similarly, most kids don't think "I want to go work at a trading firm" or "I'm going to intern at Google my freshman year" until they go to a top school and see what their classmates are doing, and realize they can do the same things. This alone gives kids from top schools a huge advantage in the job market.
