Spring data repository not found at compile time - spring

Question

I am trying to use Spring data and repositories in a Spring Boot application, but I have an error when compiling the project.
Here is my Entity :
package fr.investstore.model;
import javax.persistence.Id;
...
#Entity
public class CrowdOperation {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
public Long id;
#Enumerated(EnumType.STRING)
public RepaymentType repaymentType;
...
}
And the corresponding Repository:
package fr.investstore.repositories;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.stereotype.Repository;
import fr.investstore.model.CrowdOperation;
public interface CrowdOperationRepository extends CrudRepository<CrowdOperation, Long> {
}
I use it in a WS controller, generating a repository through the Autowired annotation:
package fr.investstore.ws;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RequestMapping;
...
#Controller
#EnableAutoConfiguration
public class SampleController {
#Autowired
private CrowdOperationRepository crowdOperationRepository;
#RequestMapping(path = "/", method = RequestMethod.GET)
#ResponseBody
public String getOperations(#RequestParam(required=true, defaultValue="Stranger") String name) {
crowdOperationRepository.save(new CrowdOperation());
return "Hello " + name;
}
}
And the code of the application:
package fr.investstore;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import fr.investstore.ws.SampleController;
#SpringBootApplication
public class InvestStoreApplication {
public static void main(String[] args) {
SpringApplication.run(SampleController.class, args);
}
}
But when compiling the project I get:
APPLICATION FAILED TO START
Description: Field crowdOperationRepository in
fr.investstore.ws.SampleController required a bean of type
'fr.investstore.repositories.CrowdOperationRepository' that could not
be found.
Action: Consider defining a bean of type
'fr.investstore.repositories.CrowdOperationRepository' in your
configuration.
Woudn't Spring automatically generate a bean for the repository through the interface?
How can I resolve this?
EDIT: I also tried to put the Repository annotation (from org.springframework.stereotype.Repository) onto CrowdOperationRepository, but I got the same error

Answer 1

While creating a spring-boot application, we need to keep some point in our mind like
Always keep main class (class with `#SpringBootApplication annotation) on the top level package and other classes should lie under sub-packages.
Always mark your bean classes with proper annotation e.g. all repositories should be marked by #Repository annotation, all service implementation classes should be marked with #Service, other component classes should be marked by #Component, class which defines our beans should be marked as #Configuration
Enable the feature which you are using e.g. #EnableJpaRepositories, #EnableTransactionManagement, #EnableJpaAuditing, these annotations also provides functionality which let us define which package spring needs to scan.
So in your case, you need to mark InvestStoreApplication class with #EnableJpaRepositories annotation and CrowdOperationRepository with #Repository.

Answer 2

you have to tell your spring boot application to load JPA repositories.
copy this one to your application class
it will auto-scan your JPA repository and load it in your spring container even if you do not define your interface with #Repository it will wire that bean in your dependent class.
#EnableJpaRepositories(basePackages = { "fr.investstore.repositories" })

Answer 3

Thank to #JBNizet for his comment, that made it working.
I create this answer since he did not:
Replace SpringApplication.run(SampleController.class, args); with SpringApplication.run(InvestStoreApplication.class, args);. And remove the useless #EnableAutoConfiguration on your controller.

Answer 4

Annotating your entity class as shown as spring hint below to allow spring get a valid repository bean
Spring Data JPA - Could not safely identify store assignment for repository candidate interface com.xxxxx.xxxxRepository.
If you want this repository to be a JPA repository, consider annotating your entities with one of these annotations: javax.persistence.Entity, javax.persistence.MappedSuperclass (preferred),
or consider extending one of the following types with your repository: org.springframework.data.jpa.repository.JpaRepository.
2022-05-06 12:32:12.623 [ restartedMain] INFO [.RepositoryConfigurationDelegate:201 ] - Finished Spring Data repository scanning in 3 ms. Found 0 JPA repository interfaces.