http://docs.spring.io/spring/docs/4.3.4.BUILD-SNAPSHOT/spring-framework-reference/htmlsingle/#beans-annotation-config 写道
As with Spring-managed components in general, the default and most common scope for autodetected components is singleton. However, sometimes you need a different scope which can be specified via the @Scope annotation. Simply provide the name of the scope within the annotation:
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When using certain non-singleton scopes, it may be necessary to generate proxies for the scoped objects. The reasoning is described in the section called “Scoped beans as dependencies”. For this purpose, a scoped-proxy attribute is available on the component-scan element. The three possible values are: no, interfaces, and targetClass. For example, the following configuration will result in standard JDK dynamic proxies:
---spring 默认是singleton的，如果你不用singleton，需要用代理？
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The use of <context:component-scan> implicitly enables the functionality of <context:annotation-config>. There is usually no need to include the <context:annotation-config> element when using <context:component-scan>.
----当使用了<context:component-scan> ，<context:annotation-config>就不需要了