java - Hibernate 4 复合 id NonUniqueObjectException

Question

将我的项目从 Hibernate 3 升级到 Hibernate 4 时抛出 NonUniqueObjectException。我出于测试目的创建了最小的 Hibernate 4 项目，并设法通过以下方式重现此异常:

• 具有实体 House，以及另一个具有包含 House 实体的复合 id 的实体 Door

  <class dynamic-insert="true" dynamic-update="true" name="entity.Door" select-before-update="true" table="DOOR">
  <composite-id name="id" class="DoorHousePK">
      <key-many-to-one class="entity.House" column="HOUSEID" name="house"/>
      <key-property column="DOORID" name="doorId" type="string"/>
  </composite-id>
  

• 然后在同一个事务中获取房屋，然后通过复合 ID 获取门:

(Door)session.get(Door.class, doorHousePK)

这是 House 的 hbm 文件:

<class dynamic-insert="true" dynamic-update="true" name="entity.House" select-before-update="true" table="HOUSE">
        <id column="ID" name="id" type="int"/>
        <property column="squarefeet" name="squareFeet" not-null="false" type="int"/>
        <property column="address" length="255" name="address" not-null="false" type="string"/>
        <property column="color" length="32" name="color" not-null="false" type="string"/>
        <property column="description" name="description" not-null="false" type="materialized_clob"/>
    </class>

，以及错误的堆栈跟踪:

INFO: HHH000327: Error performing load command : org.hibernate.NonUniqueObjectException: A different object with the same identifier value was already associated with the session : [entity.House#1]
Exception in thread "main" org.hibernate.NonUniqueObjectException: A different object with the same identifier value was already associated with the session : [entity.House#1]
    at org.hibernate.engine.internal.StatefulPersistenceContext.checkUniqueness(StatefulPersistenceContext.java:617)
    at org.hibernate.event.internal.AbstractReassociateEventListener.reassociate(AbstractReassociateEventListener.java:74)
    at org.hibernate.event.internal.DefaultLockEventListener.onLock(DefaultLockEventListener.java:95)
    at org.hibernate.internal.SessionImpl.fireLock(SessionImpl.java:774)
    at org.hibernate.internal.SessionImpl.fireLock(SessionImpl.java:767)
    at org.hibernate.internal.SessionImpl.access$1800(SessionImpl.java:176)
    at org.hibernate.internal.SessionImpl$LockRequestImpl.lock(SessionImpl.java:2491)
    at org.hibernate.loader.plan.exec.internal.EntityLoadQueryDetails$EntityLoaderRowReader.addKeyManyToOnesToSession(EntityLoadQueryDetails.java:263)
    at org.hibernate.loader.plan.exec.internal.EntityLoadQueryDetails$EntityLoaderRowReader.readRow(EntityLoadQueryDetails.java:247)
    at org.hibernate.loader.plan.exec.process.internal.ResultSetProcessorImpl.extractResults(ResultSetProcessorImpl.java:129)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:138)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:102)
    at org.hibernate.loader.entity.plan.AbstractLoadPlanBasedEntityLoader.load(AbstractLoadPlanBasedEntityLoader.java:186)
    at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:4126)
    at org.hibernate.event.internal.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:503)
    at org.hibernate.event.internal.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:468)
    at org.hibernate.event.internal.DefaultLoadEventListener.load(DefaultLoadEventListener.java:213)
    at org.hibernate.event.internal.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:275)
    at org.hibernate.event.internal.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:151)
    at org.hibernate.internal.SessionImpl.fireLoad(SessionImpl.java:1070)
    at org.hibernate.internal.SessionImpl.access$2000(SessionImpl.java:176)
    at org.hibernate.internal.SessionImpl$IdentifierLoadAccessImpl.load(SessionImpl.java:2551)
    at org.hibernate.internal.SessionImpl.get(SessionImpl.java:955)

当将这个最小项目恢复到 Hibernate 3 时，异常消失了，一切正常。

Hibernate 3 和 Hibernate 4 在复合标识处理方面有什么区别？我怎样才能使它在 Hibernate 4 中工作？

Answer 1

我最近从 hibernate 3 迁移到 4，其中两个表具有复合 ID 并通过复合外键相互关联。完全相同的配置在两个版本中都运行良好。因此，就 composite-id 功能的基本概念而言，没有区别。

您应该为 hibernate API 启用调试，即在日志属性文件中将 org.hibernate.* 的调试级别设置为 DEBUG，以查看正在触发哪些 SQL。这将帮助您查看 hibernate 是否触发了任何其他/意外的 SQL。