Spring Boot JPA CrudRepository

springspring-bootspring-dataspring-data-jpa

I'm working with Spring Boot + Spring Data JPA and facing this problem when trying to inject a class that extends CrudRepository:

Caused by: org.springframework.beans.factory.BeanCreationException:
Error creating bean with name 'topicRepository': Could not resolve
matching constructor (hint: specify index/type/name arguments for
simple parameters to avoid type ambiguities)

Repository Class:

public interface TopicRepository extends CrudRepository<Topic, Integer> {}

Service Class:

@Service
public class TopicService {

      @Autowired
      private TopicRepository topicRepository;
}

Any suggestions?

Best Answer

I was having the same issue, and I fixed it by switching Spring Boot versions. Changing the Spring Data JPA versions did nothing (this is where I assumed the bug would be), so I think there is a bug in Spring Boot version 1.5.1. I switched back to version 1.4.3 and the error was gone. I didn't try subsequent/different versions, so you may just have to experiment with your dependencies and their versions.

For the record, you can have your service class annotated with @Repository, it shouldn't make any difference. I've been setting these apps up the same way using the service/dao pattern, and it has never been too picky with the annotations. Hopefully this may help others whose Spring Boot development flow suddenly throws an error!

Related Solutions

Java – What’s the difference between @Component, @Repository & @Service annotations in Spring

From Spring Documentation:

The @Repository annotation is a marker for any class that fulfils the role or stereotype of a repository (also known as Data Access Object or DAO). Among the uses of this marker is the automatic translation of exceptions, as described in Exception Translation.

Spring provides further stereotype annotations: @Component, @Service, and @Controller. @Component is a generic stereotype for any Spring-managed component. @Repository, @Service, and @Controller are specializations of @Component for more specific use cases (in the persistence, service, and presentation layers, respectively). Therefore, you can annotate your component classes with @Component, but, by annotating them with @Repository, @Service, or @Controller instead, your classes are more properly suited for processing by tools or associating with aspects.

For example, these stereotype annotations make ideal targets for pointcuts. @Repository, @Service, and @Controller can also carry additional semantics in future releases of the Spring Framework. Thus, if you are choosing between using @Component or @Service for your service layer, @Service is clearly the better choice. Similarly, as stated earlier, @Repository is already supported as a marker for automatic exception translation in your persistence layer.

Annotation	Meaning
`@Component`	generic stereotype for any Spring-managed component
`@Repository`	stereotype for persistence layer
`@Service`	stereotype for service layer
`@Controller`	stereotype for presentation layer (spring-mvc)

Java – difference between CrudRepository and JpaRepository interfaces in Spring Data JPA

JpaRepository extends PagingAndSortingRepository which in turn extends CrudRepository.

Their main functions are:

CrudRepository mainly provides CRUD functions.
PagingAndSortingRepository provides methods to do pagination and sorting records.
JpaRepository provides some JPA-related methods such as flushing the persistence context and deleting records in a batch.

Because of the inheritance mentioned above, JpaRepository will have all the functions of CrudRepository and PagingAndSortingRepository. So if you don't need the repository to have the functions provided by JpaRepository and PagingAndSortingRepository , use CrudRepository.

Best Answer

Related Solutions

Java – What’s the difference between @Component, @Repository & @Service annotations in Spring

Java – difference between CrudRepository and JpaRepository interfaces in Spring Data JPA

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