我在 spring boot 專案中使用 jpa 投影來獲取一些值。我有以下表格：
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)
);
以下物體：
@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;
}
存盤庫：
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();
}
觀點是：
public interface RentalContractView {
Long getRentalContractId();
Long getObjectId();
Long getPropertyId();
}
當我呼叫存盤庫方法時，我可以看到我正在獲取結果和確切數字，但是在呼叫該方法getRentalContractId()時，即使應該有一個值（在資料庫中檢查）并且其他兩個欄位沒有被映射。
我也嘗試過創建類并映射它們，但仍然無法正常作業。
uj5u.com熱心網友回復：
您必須為列提供別名以匹配界面中的名稱：
@Query(value = "SELECT "
"rental_contract_id as rentalContractId "
"object_id as objectId "
"property_id as propertyId"
"from rental_contract", nativeQuery = true)
沒有命名策略，因為您沒有使用物體。
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