Override bean definition in java config

Question

I have a configuration class

@Configuration
public class FooConfig{
  @Bean
  public FooService fooService() { ... }
  @Bean
  public AbcService abcService() { ... }
}

That class is defined in a lib that I can't change. I have a project where FooService is used in many places. In my project I have another configuration class

@Configuration
@Import({
  FooConfig.class,
   
})
public class BarConfig{
  @Autowired AbcService abc;
  ...    
}

AbcService is used here because there are services which depends on that service and those services are declared in BarConfig. However, FooService is not used here(it is used only in controllers)

I need to change the implementation of FooService. Can I define new FooService bean in BarConfig? Will it override already present definition which is imported via FooConfig?

Can you subclass `FooConfig` and then not include it in your context scan? — chrylis -cautiouslyoptimistic-, May 08 '14 at 16:34
it's a bad idea, special hook for only one case. I suggest `BarConfig` to be the root configuration class — maks, May 08 '14 at 16:42
I mean `BarConfig extends FooConfig` with an overriding method. (Or your own `MyFooConfig` and import that instead.) — chrylis -cautiouslyoptimistic-, May 08 '14 at 16:49
I meant `BarConfig extends FooConfig` is a bad idea. What if I have several such `FooConfig`'s? — maks, May 08 '14 at 16:55

score 16 · Answer 1 · edited May 23 '17 at 10:31

16

You can redefine the same bean name multiple times, the spring container will take the last bean definition processed for a given name to be the one that wins. In your case, as the core project that contains the configuration you can't change does not depend on any of the beans you define in your project, it will work fine if you redefine the FooService bean. there was lot of answers about how to override bean defintions before, you can have a look to have more informations.

edited May 23 '17 at 10:31

Community

1
1

answered May 13 '14 at 01:11

Centonni

372
1
5

I can't change `FooConfig`. What is the id of a `FooService` bean defined there? It is not specified explicitly. If I know the id, I will be able to override it as you described – maks May 13 '14 at 10:54
1

With java based config,the method name annotated with `@Bean` works as bean ID. In your case `fooService` will assume the role of id. – Centonni May 13 '14 at 12:20

Override bean definition in java config

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