爲什麼Spring JPA不初始化LAZY屬性MyChildEntity.myParentEntity
(所有字段爲空)?即使在事務中,Spring JPA也不初始化懶惰屬性
我試圖使用Hibernate.initialize
和@Transactional
,但這沒有幫助。
我的服務:
@Service
@Transactional
public class MyService {
@Resource
private MyChildEntityRepository myChildEntityRepository;
@Resource
private MyParentEntityRepository myParentEntityRepository;
@PostConstruct
public void init() {
MyParentEntity p = myParentEntityRepository.save(new MyParentEntity("my name"));
myChildEntityRepository.save(new MyChildEntity(p, "first value"));
myChildEntityRepository.save(new MyChildEntity(new MyParentEntity(1L, "another name"), "another value"));
// At this point both MyChildEntity's are in database and have correct foreign key value
List<MyChildEntity> result = myChildEntityRepository.findAll();
//even this doesn't help, myParentEntity property still has all fields equals to null
Hibernate.initialize(result.get(0).getMyParentEntity());
MyParentEntity p2 = result.get(0).getMyParentEntity();
//trigger proxy's method to initialize lazy field
System.out.print(p2.getName()); // null
System.out.println(p2.getId()); // null
// PROBLEM: p2 has all fields equals null
// the same for result.get(1)
// BUT, this works correct - returns (1L, "my name") entity
myParentEntityRepository.findAll();
}
}
子實體:
@Entity
public class MyChildEntity {
@Id
@SequenceGenerator(sequenceName = "CHILD_SEQ", name = "ChildSeq", allocationSize = 1)
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "ChildSeq")
private Long id;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "my_parent_entity_id", referencedColumnName = "id")
private MyParentEntity myParentEntity;
@Column
private String value;
// constructors, getters, setters...
父實體:
@Entity
public class MyParentEntity {
@Id
@SequenceGenerator(sequenceName = "WORKFLOW_SEQ", name = "WorkflowSeq", allocationSize = 1)
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "WorkflowSeq")
private Long id;
@Column
private String name;
//constructors, getters, setters...
您是否缺少@JoinColumn? – BhathiyaW
@BhathiyaW我和\ @JoinColumn有同樣的問題(我更新了我的問題)。最後我意識到這是一個Intellij調試器的問題,我的不好 –