Spring Prototype bean具有不同的参数

Question

I want to inject a prototype scoped bean into a singleton. This prototype bean should only be created once for each Singleton it is injected in (which is the case by default as far as I understand). However, I do want a slightly different bean each time, so I want to be able to annotate the injection point with a custom annotation which is used when constructing the prototype bean.

The problem is, how do I find out what annotations are on the injection point?

Here's some code to see what I want to achieve:

@Component
public class X {
    @Inject
    @CustomAnnotation("Hi")
    private PrototypeBean bean;
}

Where PrototypeBean is provided by a bean method:

@Bean
public PrototypeBean prototypeBean(CustomAnnotation customAnnotation) {
    return new PrototypeBean(customAnnotation);
}

The idea is here that everywhere this PrototypeBean is injected, a new instance is created which behaves slightly differently based on the value of CustomAnnotation.

I know you can do this using the ApplicationContext (well, passing extra parameters that is, not annotations), but I'd like to keep it light-weight with simple annotations.

Answer 1

Perhaps what you need is a custom BeanPostProcessor . Section "3.2 Data Access" in this blog post, " A Spring Custom Annotation for a Better DAO " looks very similar to what you're trying to do.