Spring Bean有5个作用域，但是最近有需求在多个地方获取同一个Bean，只修改其中一个参数。那么Bean只在一个地方注入，修改属性就好，名字能一样吗？一系列问题
这个StepScope是什么鬼，5个默认的Scope能满足需求吗？
Bean scopes
| Scope | Description |
|---|---|
| singleton | Scopes a single bean definition to a single object instance per Spring IoC container. |
| prototype | Scopes a single bean definition to any number of object instances. |
| request | Scopes a single bean definition to the lifecycle of a single HTTP request; that is each and every HTTP request will have its own instance of a bean created off the back of a single bean definition. Only valid in the context of a web-aware Spring ApplicationContext. |
| session | Scopes a single bean definition to the lifecycle of a HTTP Session. Only valid in the context of a web-aware Spring ApplicationContext. |
| global session | Scopes a single bean definition to the lifecycle of a global HTTP Session. Typically only valid when used in a portlet context. Only valid in the context of a web-aware Spring ApplicationContext. |
通常我们使用的是singleton，默认也是。在测试中发现提供相同类型的Bean，需要指定不同的name标识（@Bean(“three”)），使用时对应@Qualifier(“three”)。
疑问：经测试发现提供相同类型Bean，不指定Qualifier会出错，但是在SpringBatch中指定了@StepScope却没报错，那是如何来区分应该在哪个Step中有效的呢？
通过查看StepScope文档可以发现应该还有自定义Scope的存在来实现个性化需求，见Bean scopes之4.4.5 Custom scopes。