JPQL自定义查询以使用ExampleMatcher和Pageable检索数据

Question

How to using JPQL Custom query using ExampleMatcher?

I'm trying to retrieve the child from parent size. Since I'm not allowed to add another method on the child side.

I need to filter and paging for showing the child because the child contains so-many row data.

This is my repository.

@Repository
public interface ParentRepository extends JpaRepository<Parent, String> {

    @Query(value = "SELECT c FROM Child c where c.parent.id =:id")  
    public List<Child> findChildById(String id, Example example, Pageable pageable);

}

Note: This query is working fine, if without example and pageable as parameters.

That method give me the an error :

    Error creating bean with name 'parentRepository': 
        Invocation of init method failed; nested exception is java.lang.IllegalStateException: 
        Using named parameters for method public abstract java.util.List com.example.test.ParentRepository
.findChildById(java.lang.String,org.hibernate.criterion.Example,org.springframework.data.domain.Pageable) 
        but parameter 'Optional[example]' not found in annotated query 
        'SELECT c FROM Child c where c.parent.id =:id'!

Answer 1

Parameters you pass to method annotated with @Query should be used in query, in your example this should be something like this:

@Query(value = "SELECT c FROM Child c where c.parent.id =:id")  
public List<Child> findChildById(@Param("id") String id);