如何在 JPQL 查詢中獲取 @Basic 字段

Question

實體定義是：

@Entity
@DynamicInsert
@DynamicUpdate
public class ProductInformation {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Version
    private Long version;

    private String url;
    private String price;
    private String bookName;
    private String isbn;

    @Lob
    @Basic(fetch = FetchType.LAZY)
    private String sourceFile;

    @Lob
    @Basic(fetch = FetchType.LAZY)
    private String information;

    ...
}

我使用以下 JPQL 查詢加載所有條目：

from ProductInformation

然后在導出過程中訪問帶有@Basic注釋的字段。 我可以在 SQL 日志中看到以下 output （延遲加載可見）：

select productinf0_.id as id1_0_, productinf0_.book_name as book_nam2_0_, productinf0_.isbn as isbn4_0_, productinf0_.price as price5_0_, productinf0_.url as url7_0_, productinf0_.version as version8_0_ from product_information productinf0_
select productinf_.information as informat3_0_, productinf_.source_file as source_f6_0_ from product_information productinf_ where productinf_.id=?
select productinf_.information as informat3_0_, productinf_.source_file as source_f6_0_ from product_information productinf_ where productinf_.id=?
select productinf_.information as informat3_0_, productinf_.source_file as source_f6_0_ from product_information productinf_ where productinf_.id=?
select productinf_.information as informat3_0_, productinf_.source_file as source_f6_0_ from product_information productinf_ where productinf_.id=?
select productinf_.information as informat3_0_, productinf_.source_file as source_f6_0_ from product_information productinf_ where productinf_.id=?
...

有沒有辦法在 JPQL 查詢中@Basic(fetch = FetchType.LAZY)注釋字段？

Answer 1

請參閱 entityGraph 和 LoadGraphs (javax.persistence.loadgraph) 查詢提示，它允許您指定要在實體中加載的其他字段，覆蓋惰性映射規范。 有關示例，請參見https://www.baeldung.com/jpa-entity-graph