java - EmbeddedId 属性上的 Hibernate Criteria 抛出 org.hibernate.QueryException : could not resolve property

Question

使用 Hibernate Criteria API 时，我正在努力解决 Hibernate 的一个非常奇怪的行为。我正在使用 hibernate 4.3.6 Final。我有一个像这样的AnnouncementAttribute类:

@Entity
@Table(name = "announcement_attribute")
public class AnnouncementAttribute implements Serializable {

    @EmbeddedId
    protected AnnouncementAttributePK id;

    @Column(name = "attribute_value")
    private String attributeValue;
}

以及AnnouncementAttributePK类下面:

@Embeddable
public class AnnouncementAttributePK implements Serializable {
    @ManyToOne
    @JoinColumn(name = "attribute_id")
    private Attribute attr;

    @ManyToOne
    @JoinColumn(name = "announcement_id")
    private Announcement announcement;
}

和属性类:

@Entity
@Table(name = "attribute")
public class Attribute implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(name = "attribute_type")
    private Integer attributeType;

    @Column(name = "attribute_name")
    private String attributeName;
}

我在这里省略了 getter/setter。

问题是当我尝试通过 Criteria API 访问 @EmbeddedId 属性 attr 时:

Criteria ac = session().createCriteria(AnnouncementAttribute.class);
ac.add(Restrictions.and(
                    Restrictions.eq("id.attr.attributeName", "someKey"), 
                    Restrictions.eqOrIsNull("attributeValue", "someValue")));

我得到:

org.hibernate.QueryException: could not resolve property: id.attr.attributeName of: com.example.app.domain.AnnouncementAttribute

我已经尝试为EmbeddedId 创建别名 - 仍然没有成功。

Answer 1

好吧，虽然我不相信我找到的解决方案，但无论如何我都会发布它，也许有人会发现它有用，或者也许它将成为进一步讨论的好主题。

我从AnnouncementAttributePK中删除了@Embedded

public class AnnouncementAttributePK implements Serializable {
    @ManyToOne
    @JoinColumn(name = "attribute_id")
    private Attribute attr;

    @ManyToOne
    @JoinColumn(name = "announcement_id")
    private Announcement announcement;
}

，然后在AnnouncementAttribute中我将@EmbeddedId更改为@IdClass和@Id的组合:

@Entity
@Table(name = "announcement_attribute")
@IdClass(AnnouncementAttributePK.class)
public class AnnouncementAttribute implements Serializable {

    @Id
    private Attribute attr;
    @Id
    private Announcement announcement;

    @Column(name = "attribute_value")
    private String attributeValue;
}

最后是标准:

Criteria ac = session().createCriteria(AnnouncementAttribute.class)
            .createAlias("attr", "atrib");
ac.add(Restrictions.and(
                    Restrictions.eq("atrib.attributeName", "someKey"), 
                    Restrictions.eqOrIsNull("attributeValue", "someValue")));

经过这些更改后，一切正常。我不知道为什么......无论如何我都会进一步调查它，因为它至少很奇怪。也许这与我的应用程序在 Spring Context 中运行、使用 LocalContainerEntityManagerFactoryBean 和 spring-data-jpa 以及通过解包 EntityManager 获得 org.hibernate.Session 对象有关？ :

@PersistenceContext
private EntityManager entityManager;

和 session :

private Session session(){
    return entityManager.unwrap(Session.class);
}