mongodb - EclipseLink MongoDB @ManyToOne classCastException 非常简单的示例

Question

我试图让 EclipseLink (2.4.1) 通过 MongoDB 在建立关系时按预期工作。但是...

我必须到实体:

@Entity
@NoSql(dataType="account", dataFormat=DataFormatType.MAPPED) // dataType -> collectionName, MAPPED -> because object are transformed into a MAP in MongoDB
@Table(uniqueConstraints = @UniqueConstraint(columnNames = "email"))
public class Account extends JPAMongoBaseEntity {
    @Id
    @Field(name="_id")
    @GeneratedValue
    private String id;

    @Override
    public String getId() { return id;};
    public void setId(String id) { this.id = id;};

    // Must be unique (id fonc)
    @NotNull
    @Size(min = 1, max = 256)
    @Email
    private String email;
...

和:

@Entity
@NoSql(dataType="invoice", dataFormat=DataFormatType.MAPPED) // dataType -> collectionName, MAPPED -> because object are transformed into a MAP in MongoDB
@Table(uniqueConstraints = @UniqueConstraint(columnNames = "label"))
public class Invoice extends JPAMongoBaseEntity {
    @Id
    @Field(name="_id")
    @GeneratedValue
    private String id;

... // Relations
    @ManyToOne
    private Account account;

我尝试获取所有具有 account.id = 参数的发票。 我执行此请求:

TypedQuery<Invoice> q = em.createQuery("Select i from Invoice i join i.account a where a.id=:accountId", Invoice.class);
q.setParameter("accountId", accountId);
List<Invoice> res = q.getResultList();

结果总是相同的:

Internal Exception: java.lang.ClassCastException: org.eclipse.persistence.eis.mappings.EISOneToOneMapping cannot be cast to org.eclipse.persistence.mappings.OneToOneMapping
Query: ReadAllQuery(referenceClass=Invoice jpql="Select i from Invoice i join i.account a where a.id=:accountId")

我尝试了很多东西(@JoinField、@OneToOne，...)，但我总是遇到这个异常。

任何帮助将不胜感激。

Answer 1

根据 http://wiki.eclipse.org/EclipseLink/Examples/JPA/NoSQL#Step_6_:_Querying 不支持连接。

您可以尝试使用只读基本映射来映射外键并直接在查询中访问它。或者按照此处所述为 fk 字段添加查询键 http://wiki.eclipse.org/EclipseLink/UserGuide/JPA/Basic_JPA_Development/Querying/Query_Keys

最诚挚的问候， 克里斯