java - 如何在 Hibernate 中持久化 Map>

Question

我有一个包含 MyObject 实例的 Map。 MyObject 类使用 JPA 来保存其字段:

@OneToMany(cascade = CascadeType.ALL)
@LazyCollection(LazyCollectionOption.FALSE)
private Map<String, MyObject> results = new HashMap<String, MyObject>();

我们将Map 存储的值 更改为List:

private Map<String, List<MyObject>> results = new HashMap<String, List<MyObject>>();

但是在启动时我们收到堆栈跟踪:

Caused by: org.hibernate.AnnotationException: Use of @OneToMany or @ManyToMany targeting an unmapped class: com.me.myapp.MyObject.results[java.util.List]
    at org.hibernate.cfg.annotations.CollectionBinder.bindManyToManySecondPass(CollectionBinder.java:1150)
    at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:680)
    at org.hibernate.cfg.annotations.MapBinder$1.secondPass(MapBinder.java:107)
    at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:66)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1221)
    at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:383)
    at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1206)
    at org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:673)
    at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:211)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1368)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1334)
    ... 30 more

Hibernate 不支持保留包含(作为值)List 类型的 Map 吗？或者我的注释不正确？我没有在任何文档或示例中找到此特定配置。

Answer 1

映射中存储的对象必须是oneToMany关联的目标对象(总是映射的)。您不能在那里存储任意对象或集合。