java - 在 JPA Hibernate 中映射队列集合

Question

是否可以在 JPA/hibernate 中进行以下集合映射

@OneToMany(cascade={CascadeType.PERSIST, CascadeType.REFRESH, CascadeType.MERGE},
fetch=FetchType.LAZY,mappedBy="parent")

private Deque<Child> childrens;

它抛出错误

Illegal attempt to map a non collection as a @OneToMany, @ManyToMany or @CollectionOfElements

我正在使用 JPA 2.0 和 Hibernate 3

Answer 1

不，JPA 不支持双端队列。在 JPA 2.0 规范中，这是按以下方式解释的:

Collection-valued persistent fields and properties must be defined in terms of one of the following collection-valued interfaces regardless of whether the entity class otherwise adheres to the JavaBeans method conventions noted above and whether field or property access is used: java.util.Collection, java.util.Set, java.util.List[3], java.util.Map. The collection implementa- tion type may be used by the application to initialize fields or properties before the entity is made persistent. Once the entity becomes managed (or detached), subsequent access must be through the interface type.

我建议添加到提供所需 Deque 功能的实体方法(或将 View 作为 Deque 公开到持久列表)。其他可能性是评论中建议的自定义集合 (Thor84no)。