第2个回答 2020-08-11
没有优先级说法
@Component
This is a generic annotation and can be applied to any class of the application to make it a spring managed component(simply, generic stereotype for any spring managed component). when the classpath is scanned by the spring’s component-scan (@ComponentScan) feature, it will identify the classes annotated with @Component annotation (within the given package) and create the beans of such classes and register them in the ApplicationContext. @Component is a class level annotation and its purpose it to make the class as spring managed component and auto detectable bean for classpath scanning feature.
if you want to know more about @Component and other stereo type annotations, it is recommended to look at this article.
@Bean
@Bean is used to explicitly declare and register a bean (as a configuration bean) in Spring IOC container that is returned from a method. @Bean is a method level annotation and it is used within a class that is annotated with @Configuration. Simply, @Bean annotation is used to register the bean returned by a method as a spring configuration bean in IOC Container. @Bean is only a method level annotation and it cannot be used with classes and object declaration.
@Bean annotation indicates that a method produces a bean that should be managed by the Spring container.
To declare a bean, simply annotate a method with the @Bean annotation. When JavaConfig encounters such a method, it will execute that method and register the return value as a bean within a ApplicationContext. By default, the bean name will be the same as the method name.The following is a simple example of a @Bean method declaration.
@Configurationpublic class ApplicationConfig { @Bean
public User adminUserProfile()
{
return new User("Chathuranga","Tennakoon");
}
}
In the ApplicationConfig class, you can see that we first use the @Configuration annotation to inform Spring that this is a Java-based configuration file. Afterward, the @Bean annotation is used to declare a Spring bean and the DI requirements.
The @Bean annotation is equivalent to the <bean> tag, the method name is equivalent to the id attribute within the <bean> tag.
I hope that after reading this article, you have got a clear idea about the real purpose and use of @Bean and @Component annotations.