What is the Spring DI equivalent of CDI's InjectionPoint?

问题

I would like to create a Spring's bean producer method which is aware who invoked it, so I've started with the following code:

@Configuration
public class LoggerProvider {

    @Bean
    @Scope("prototype")
    public Logger produceLogger() {
        // get known WHAT bean/component invoked this producer 
        Class<?> clazz = ...

        return LoggerFactory.getLogger(clazz);
    }
}

How can I get the information who wants to get the bean injected?

I'm looking for some equivalent of CDI's InjectionPoint in Spring world.

回答1:

As far as I know, Spring does not have such a concept.

Then only thing that is aware of the point that is processed is a BeanPostProcessor.

Example:

@Target(PARAMETER)
@Retention(RUNTIME)
@Documented
public @interface Logger {}

public class LoggerInjectBeanPostProcessor implements BeanPostProcessor {   
    public Logger produceLogger() {
        // get known WHAT bean/component invoked this producer
        Class<?> clazz = ...    
        return LoggerFactory.getLogger(clazz);
    }


    @Override
    public Object postProcessBeforeInitialization(final Object bean,
            final String beanName) throws BeansException {
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(final Object bean,
            final String beanName) throws BeansException {

        ReflectionUtils.doWithFields(bean.getClass(),
                new FieldCallback() {
                     @Override
                     public void doWith(final Field field) throws IllegalArgumentException, IllegalAccessException {
                         field.set(bean, produceLogger());
                     }
                },
                new ReflectionUtils.FieldFilter() {
                     @Override
                     public boolean matches(final Field field) {
                          return field.getAnnotation(Logger.class) != null;
                     }
                });

        return bean;
    }
}

回答2:

Spring 4.3.0 enables InjectionPoint and DependencyDescriptor parameters for bean producing methods:

@Configuration
public class LoggerProvider {

    @Bean
    @Scope("prototype")
    public Logger produceLogger(InjectionPoint injectionPoint) {
        Class<?> clazz = injectionPoint.getMember().getDeclaringClass();

        return LoggerFactory.getLogger(clazz);
    }
}

By the way, the issue for this feature SPR-14033 links to a comment on a blog post which links to this question.

来源：https://stackoverflow.com/questions/9685316/what-is-the-spring-di-equivalent-of-cdis-injectionpoint

标签

Spring

dependency-injection

java-ee-6

cdi

producer