我在 Spring Boot 项目中使用 jpa 投影来获取一些值。我有下表:
create table `rental_contract`
(
`rental_contract_id` bigint(20) not null,
`object_id` bigint(20) default null,
`property_id` bigint(20) default null,
primary key (rental_contract_id),
foreign key (property_id, object_id) references property_object (property_id, object_id)
);
以下实体:
@Entity
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@NamedEntityGraph(
name = "RentalContract.WithPropertyObjects",
attributeNodes = {
@NamedAttributeNode(value = "propertyObject", subgraph =
"RentalContract.WithPropertyObjects.Properties")
},
subgraphs = {
@NamedSubgraph(name = "RentalContract.WithPropertyObjects.Properties",
attributeNodes = {
@NamedAttributeNode(value = "property")
})
}
)
public class RentalContract {
@Id
private Long rentalContractId;
@JoinColumns({
@JoinColumn(name = "object_id"),
@JoinColumn(name = "property_id"),
})
@ManyToOne(fetch = FetchType.LAZY)
private PropertyObject propertyObject;
}
存储库:
public interface RentalContractRepository extends JpaRepository<RentalContract, Long> {
Optional<RentalContract>
findByPropertyObject_ObjectIdAndPropertyObject_Property_PropertyId(Long objectId, Long
propertyId);
@Override
@EntityGraph(value = "RentalContract.WithPropertyObjects")
List<RentalContract> findAll();
@Query(value = "SELECT * from rental_contract", nativeQuery = true)
List<RentalContractView> getAllWithObjectsAndProperties();
}
View 是:
public interface RentalContractView {
Long getRentalContractId();
Long getObjectId();
Long getPropertyId();
}
当我调用存储库方法时,我可以看到我正在获取结果和确切的数字,但是当调用方法 getRentalContractId()
时,即使应该有一个值,我也得到 null (在数据库中检查)并且其他两个字段没有被映射。
我也尝试过创建类并映射它们,但仍然不起作用。
最佳答案
您必须为列提供别名以匹配界面中的名称:
@Query(value = "SELECT " +
"rental_contract_id as rentalContractId " +
"object_id as objectId " +
"property_id as propertyId" +
"from rental_contract", nativeQuery = true)
没有命名策略,因为您没有使用实体。
关于java - JPA 投影获取结果但未将列与界面 View 中的方法匹配,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/69622830/