@ComponentScan具有多个配置类:基于注释的配置 [英] @ComponentScan with multiple configuration class : Annotation Based Configuration

问题描述

根据Spring Doc-

配置与@Configuration类一起使用的组件扫描指令.提供与Spring XML的<context:component-scan>元素并行的支持.

在我的spring Web应用程序中，有多个标记为@Configuration的文件，以便在Spring容器中注册@component bean-

问题1-我们可以在@Configuration类的任何或所有 @Configuration类中使用@ComponentScan 吗? >

问题2

我也在春季看到了文档

@Configuration
@ComponentScan(basePackageClasses = { MyConfiguration.class })
public class MyConfiguration extends WebMvcConfigurerAdapter {
...
}

为什么在这里扫描配置类本身.

基本上，我对@ComponentScan的理解是扫描和注册立体声类型bean(例如-@componant，@Controller，@Services等.)，为什么我们要注册@Configuration Bean.

解决方案

问题1-

是的，您可以使用@ComponentScan在任何配置在弹簧容器中的配置豆中注册.您可以通过任何方式将Bean注册到容器中以下方式之一-

1. 使用@Configuration在rootcontext中注册Bean或 dispatchersevletcontext.
2. 将类导入任何@Configuration bean(已在容器中注册).

让我们说-您有要扫描组件的MvcConfig类-

@ComponentScan(basePackages = {"xxxx","yyyy","zzzz"})
@Configuration
public class MvcConfig  {
....
}

要在容器中注册MvcConfig，您必须做

任何一个

new AnnotationConfigWebApplicationContext().register(MvcConfig.class);

或

new AnnotationConfigWebApplicationContext().register(AnotherConfig.class);

@Configuration
@Import({MvcConfig.class})
public class AnotherConfig  {
....
}

您的问题2-

spring不仅在注册MyConfiguration.class，而且还在注册MyConfiguration的程序包中存在的所有组件类.

As per Spring Doc-

Configures component scanning directives for use with @Configuration classes. Provides support parallel with Spring XML's <context:component-scan> element.

In my spring web application there are multiple files those are marked @Configuration,in order to register @component bean in spring container-

Question1- Can we use @ComponentScan in any of the @Configuration class or in all @Configuration classes?

Question2-

Also I seen in spring doc

@Configuration
@ComponentScan(basePackageClasses = { MyConfiguration.class })
public class MyConfiguration extends WebMvcConfigurerAdapter {
...
}

Why here scanning for configuration class itself.

edit: Basically my understanding with @ComponentScan is to scan and register stereo type bean(ex- @componant,@Controller,@Services etc..),why we are registering @Configuration Bean.

解决方案

For your Question 1 -

yes, you can register a bean using @ComponentScan in any of the configuration bean which is registered in spring container.you can register a bean into container by any of the following way-

1. Use @Configuration to register bean in rootcontext or dispatchersevletcontext.
2. Import a class in any @Configuration bean (which is already registered in container).

Let say- you have MvcConfig class in which you are scanning component-

@ComponentScan(basePackages = {"xxxx","yyyy","zzzz"})
@Configuration
public class MvcConfig  {
....
}

To register MvcConfig in container you must do-

Either

new AnnotationConfigWebApplicationContext().register(MvcConfig.class);

Or

new AnnotationConfigWebApplicationContext().register(AnotherConfig.class);

@Configuration
@Import({MvcConfig.class})
public class AnotherConfig  {
....
}

For your Question 2 -

Here spring is not only registering MyConfiguration.class but also all the component classes those are present in the package in which MyConfiguration defined.

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