CODEWITHSUNDEEP
javaspringdependency-injectionconstructor-injection
shikharraje
shikharraje

Reputation: 143

@Autowire Spring Bean with Injected Constructor args?

I have a project structure similar to the one linked here: https://stackoverflow.com/a/29583882/1243462 . I have a util library containing a Service class in one JAR, meant to be consumed from another Java library/Maven project. However, my Service class itself uses Constructor Injection. So, where the original question had:

@Service
public class PermissionsService { ... }

I have

@Service
public class PermissionsService {

  public PermissionsService(@Autowired PermissionsDao dao) { 
   //assign private dao field to autowired dao
  }

}

And, like the original post, I want to create an instance of PermissionsService and inject it into my client/consumer application. I'm not sure of how to create a Configuration class.

 @Configuration
 public class PersistenceConfig {

   public PermissionsService getPermissionsServiceBean() {
     //What goes here?
   }
}

For now, I have a workaround where I replaced the @Autowired PermissionsDao constructor argument with a field injection, and having a no-args constructor. This allows me to:

 @Configuration
 public class PersistenceConfig {

   public PermissionsService getPermissionsServiceBean() {
     return new PermissionsService();
   }
}

But, since Field injection is discouraged, what is the right way to structure this code?

Upvotes: 0

Views: 177

Answers (1)

user10367961
user10367961

Reputation:

In your main module

@Configuration
@Import(PersistenceConfig.class)
public class ServiceConfig() {

}

In your utils module

@Configuration
@ComponentScan(basePackages = {"path-to-persistence-service-and-any-dependencies"})
public class PersistenceConfig {

}

The fact that you use constructor injection for PermissionsDao should not matter if you get the configuration right.

Upvotes: 2

Related Questions