java - Hibernate 不会在 getter 处获取 @Id 注释

Question

问题

在我当前的项目中，我得到了这个AnnotationException:

org.hibernate.AnnotationException: No identifier specified for entity: my.package.EntityClass

有缺陷的代码

问题是由@Id注解引起的，我把它从field移到了getter:

@Entity
@Table(name = "MY_TABLE")
public class EntityClass extends BaseEntityClass {

  private long id;

  @Override
  public void setId(long id) {
    this.id = id;
  }

  @Override
  @Id
  @SequenceGenerator(name = "FOOBAR_GENERATOR", sequenceName = "SEQ_MY_TABLE", allocationSize = 1, initialValue = 1)
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "FOOBAR_GENERATOR")
  public long getId() {
    return this.id;
  }

}

工作代码

当我改为注释 id 属性时，它工作正常:

@Entity
@Table(name = "MY_TABLE")
public class EntityClass extends BaseEntityClass {

  @Id
  @SequenceGenerator(name = "FOOBAR_GENERATOR", sequenceName = "SEQ_MY_TABLE", allocationSize = 1, initialValue = 1)
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "FOOBAR_GENERATOR")
  private long id;

  @Override
  public void setId(long id) {
    this.id = id;
  }

  @Override
  public long getId() {
    return this.id;
  }

}

文档引用

Hibernate documentation状态:

By default the access type of a class hierarchy is defined by the position of the @Id or @EmbeddedId annotations. If these annotations are on a field, then only fields are considered for persistence and the state is accessed via the field. If there annotations are on a getter, then only the getters are considered for persistence and the state is accessed via the getter/setter. That works well in practice and is the recommended approach.

问题

我的类有额外的属性，我想在其中注释 getter。所以我还需要在 getter 处添加 @Id 注释。

这在之前的其他项目中运行良好，但这次 Hibernate 似乎没有在 getter 被注释时获取实体的标识符。

• 我是否需要更改任何其他配置属性？

• 或者这种行为是否在 Hibernate 版本之间发生了变化？

Answer 1

您需要始终对所有 getter 使用 @Id。确保没有使用 @Id 而不是 getters 注释的字段。混合和匹配会阻止它正常工作。