EclipseLink JPA NamedQuery 在 Set 类型的字段中找不到 .size 属性

Question

我正在使用 EclipseLink 将一些数据库方法从 Hibernate 迁移到 JPA，并且有一个 NamedQuery 有问题，它使用 Set 中的 .size 方法对结果进行排序。这是我的实体 class，其中包含导致问题的查询和字段：

@Entity
@Table(name = "PRODUCT")
@DiscriminatorValue(value = "Bundle")
@NamedQueries({@NamedQuery(name = BundleProduct.findProductBundles, query = "select distinct bundle from BundleProduct bundle inner join bundle.products as product inner join bundle.services as service where service.name = :service and product in (:products) and not exists (select product2 from BundleProduct bundle2 join bundle2.products as product2 where bundle = bundle2 and product2 not in (:products)) order by product.size desc, bundle.name")})
public class BundleProduct extends Product
{

    @ManyToMany
    @JoinTable(name = "SERVICEPRODUCT",
            joinColumns = {@JoinColumn(name = "ITSPRODUCT")},
            inverseJoinColumns = {@JoinColumn(name = "ITSSERVICE")})
    private Set<SingleProduct> products;

这会导致我的应用程序服务器 (Weblogic 12.2.1.0.0) 发生异常：

Exception Description: Deployment of PersistenceUnit [myunit] failed. Close all factories for this PersistenceUnit.
Internal Exception: Exception [EclipseLink-0] (Eclipse Persistence Services - 2.6.1.v20150916-55dc7c3): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Problem compiling [select distinct bundle from BundleProduct bundle join bundle.products as product join bundle.services as service where service.name = :service and product in (:products) and not exists (select product2 from BundleProduct bundle2 join bundle2.products as product2 where bundle = bundle2 and product2 not in (:products)) order by product.size desc, bundle.name]. [349, 361] The state field path 'product.size' cannot be resolved to a valid type.

"order by" 子句的第一部分曾经是 "bundle.products.size"，我的印象是将其更改为 "product.size" 应该可以解决问题，但我仍然遇到异常。

在我研究这个问题的过程中，我发现多篇文章都说 IDE 似乎可以自动完成这些查询，但后来就不起作用了。我正在使用 IDEA 14.1.5.

Answer 1

The state field path 'product.size' cannot be resolved to a valid type.

是的 "size" 不存在，但是 JPQL 有 SIZE(...) 来处理这个。

ORDER BY SIZE(products) DESC, bundle.name

一如既往，请参阅 JPQL 参考文档以查看可用的功能，例如 this one。

EclipseLink JPA NamedQuery 在 Set 类型的字段中找不到 .size 属性

EclipseLink JPA NamedQuery can not find .size Attribute in field of type Set

java

jpa

named-query

eclipselink

jpql