Spring Bean Alias in JavaConfig

Question

I have a @Service annotated class which provides core functionality which I can use in all my projects:

@Service
public class MyService {}
         


        

Answer 1

With small amount of configuration and one ImportBeanDefinitionRegistrar you can configure bean aliases via Java configuration. You can check bean-alias library project for reference - developed for the needs of my projects. Feel free to modify and/or copy the source into your own project in case the spring version used in it does not work with your setup.

Once you have the library on your path, you declare an alias through the annotation:

@Configuration
@BeanAlias(name = "fromName", alias = "toName")
public class ExampleConfiguration {
}

That's it.

How it works is that with the annotation we import a ImportBeanDefinitionRegistrar implementation

@Import(BeanAliasBeanRegistrar.class)
public @interface BeanAlias {
}

which registers the alias in the BeanDefinitionRegistry

class BeanAliasBeanRegistrar implements ImportBeanDefinitionRegistrar, PriorityOrdered {

    @Override
    public void registerBeanDefinitions(AnnotationMetadata metadata, BeanDefinitionRegistry registry) {
      ...
      registerAlias(registry, metadata.getAnnotationAttributes(BeanAlias.class.getName()));
    }

    private void registerAlias(BeanDefinitionRegistry registry, Map attributes) {
      ...
      registry.registerAlias(name, alias);
    }
}