问题描述

在 Spring 应用程序中充当 bean 的类是否同时需要 @Component 和 @Named?

Does a class which will act as a bean in a Spring application require both @Component and @Named at the same time?

如果两者都这样使用有什么意义?

What is the significance if both are used so?

我尝试在网上搜索并查看了这些注释的标准文档，发现它们有点混乱.

I tried searching the net as well as saw the standard documentation of these annotations and found them a bit confusing.

如果 @Named 注释没有为 bean 指定任何名称，那么最终应用程序会采用哪个名称?

Finally which name is taken by the application if the @Named annotation does not specify any name for the bean?

推荐答案

@Component 和 @Named 是基本上做同样事情的注解，但来自不同的 API.

@Component and @Named are annotations that basically do the same thing, but come from different APIs.

@Component 属于 Spring API.它将要自动检测为 bean 的类标记为可以选择允许您为该 bean 指定一个名称 (@Component("foo")).如果没有明确的名称规范，检测到的 bean 将获得一个从其类的名称派生的默认名称.

@Component belongs to Spring API. It marks class to be autodetected as a bean and optionally allows you to specify a name for that bean (@Component("foo")). Without explicit name specification detected bean will get a default name derived from the name of its class.

@Named 属于 javax.inject API.它将类标记为自动检测为 bean，并要求您指定名称.

@Named belongs to javax.inject API. It marks class to be autodetected as a bean and requires you to specify a name.

Spring 支持这两种 API.在同一个类中使用这两个注解是没有意义的，因为它们提供相同的功能.

Spring supports both these APIs. It doesn't make sense to use both annotations at the same class since they provide the same functionality.

另请参阅:

• 3.10 类路径扫描和托管组件

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