Spring Data：用规范调用findAll的抽象基服务中的JPA存储库

Question

我希望了解通用存储库模式。我有一个由抽象服务实现的通用服务接口，抽象服务由所有服务实现扩展。我希望确保所有CRUD操作和根据标准/规范进行的搜索都发生在抽象服务中。

我的所有存储库都是扩展JpaRepository和JPaspecificationExecutor的接口。但是，我不能在抽象服务中使用autowired存储库执行findAll（规范，分页）。

服务接口：

public interface GenericFoo<T, S> {
     public List<T> search(S criteria, Pageable pageable) {
}

抽象服务：

public abstract class Foo<T, S> implements GenericFoo<T, S> {
    @Autowired
    private JpaRepository<T, Long> repository;

    public List<T> search(S criteria, Pageable pageable) {
         //throws compilation error
         repository.findAll(getSpecification(criteria), pageable);
    }

    protected abstract Specification<T> getSpecification(S criteria);
}

ServiceImpl：

@Component
@Transactional
public class BarServiceImpl extends Foo<Bar, BarSearchCriteria> implements GenericFoo {

    protected Specification<Bar> getSpecification(BarSearchCriteria criteria) {
        //implementation to be filled for each service
        return null;
    }  
}

public interface BarRepository extends JpaRepository<Bar, Long>, JpaSpecificationExecutor<Bar> {
}

public interface SimpleRepository<T> extends JpaRepository<T, Long>, JpaSpecificationExecutor<T> {
}

public abstract class BaseService<T, S> implements GenericService<T, S> {
    @Autowired
    private SimpleJpaRepository<T, Long> simpleJpaRepository;

    public List<T> search(S criteria, Pageable pageable) {
        repository.findAll(getSpecification(criteria), pageable);
    }

    protected abstract Specification<T> getSpecification(S criteria);
}

public interface BarRepository extends SimpleJpaRepository<Bar, Long> {
}

Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.springframework.data.jpa.repository.support.SimpleJpaRepository com.foopackage.barpackage.services.BaseService.simpleJpaRepository; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.data.jpa.repository.support.SimpleJpaRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:573) ~[spring-beans-4.2.8.RELEASE.jar:4.2.8.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.2.8.RELEASE.jar:4.2.8.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331) ~[spring-beans-4.2.8.RELEASE.jar:4.2.8.RELEASE]
... 22 common frames omitted
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.data.jpa.repository.support.SimpleJpaRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1380) ~[spring-beans-4.2.8.RELEASE.jar:4.2.8.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1126) ~[spring-beans-4.2.8.RELEASE.jar:4.2.8.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1021) ~[spring-beans-4.2.8.RELEASE.jar:4.2.8.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:545) ~[spring-beans-4.2.8.RELEASE.jar:4.2.8.RELEASE]
... 24 common frames omitted

Answer 1

我应该对结构进行哪些更改，以便能够利用JPaspecificationExecutor的方法？

创建和使用类似这样的中间接口应该可以做到这一点：

public interface RepositoryWithExecutor<T> extends JpaRepository<T, Long>, JpaSpecificationExecutor<Bar> {}

现在，您的BarRepository只需扩展repositorywithexecutor

附注：我认为您实际上并没有显示您正在使用的代码，因为baseService是抽象的，Spring不应该尝试实例化它。