@component and its specializations(@Controller, @service, @repository) allow for auto-detection using classpath scanning. If we see component class like @Controller, @service, @repository will be scan automatically by the spring framework using the component scan. @Bean on the other hand can only be used to explicitly declare a single bean in a configuration class. @Bean used to explicitly declare a single bean, rather than letting spring do it automatically. Its make septate declaration of bean from the class definition. In short @Controller, @service, @repository are for auto-detection and @Bean to create seprate bean from class

    - @Controller
    public class LoginController 
    { --code-- }

    - @Configuration
    public class AppConfig {
    @Bean
    public SessionFactory sessionFactory() 
    {--code-- }

@Component和@Bean做两件完全不同的事情，不应该混淆。

@Component(以及@Service和@Repository)用于使用类路径扫描自动检测和自动配置bean。在带注释的类和bean之间存在隐式的一对一映射(即每个类一个bean)。这种方法对连接的控制非常有限，因为它是纯声明性的。

@Bean用于显式地声明单个bean，而不是像上面那样让Spring自动执行。它将bean的声明与类定义解耦，并允许您按照自己的选择创建和配置bean。

回答你的问题…

是否有可能重用@Component注释而不是引入@Bean注释?

当然,可能;但他们选择不这样做，因为这两者是完全不同的。春天已经够让人迷惑了，不要再把水弄脏了。

@Bean可以有作用域，而@component不能 如 @Scope(value = WebApplicationContext.)SCOPE_REQUEST, proxyMode = ScopedProxyMode.TARGET_CLASS)

这两种方法都旨在在Spring容器中注册目标类型。

区别在于@Bean适用于方法，而@Component适用于类型。

因此，当您使用@Bean注释时，您可以在方法主体中控制实例创建逻辑(参见上面的示例)。而@Component注释则不行。

You have two ways to generate beans. One is to create a class with an annotation @Component. The other is to create a method and annotate it with @Bean. For those classes containing method with @Bean should be annotated with @Configuration Once you run your spring project, the class with a @ComponentScan annotation would scan every class with @Component on it, and restore the instance of this class to the Ioc Container. Another thing the @ComponentScan would do is running the methods with @Bean on it and restore the return object to the Ioc Container as a bean. So when you need to decide which kind of beans you want to create depending upon current states, you need to use @Bean. You can write the logic and return the object you want. Another thing worth to mention is the name of the method with @Bean is the default name of bean.

假设我想要特定的实现依赖于某种动态状态。 @Bean非常适合这种情况。

@Bean
@Scope("prototype")
public SomeService someService() {
    switch (state) {
    case 1:
        return new Impl1();
    case 2:
        return new Impl2();
    case 3:
        return new Impl3();
    default:
        return new Impl();
    }
}

然而，@Component没有办法做到这一点。