休眠:使用executeUpdate()进行批量删除不会清除一级缓存

Question

我的意图是使用executeUpdate()执行单个DELETE，而不是循环通过session.delete()，这非常健谈。

我面临的问题是，通过执行executeUpdate()，它不会从一级缓存中逐出现有的已删除实体。

这里有一个非常简单的例子：-

final Session session = sessionFactory.getCurrentSession();
System.out.println("---------------------------------");
System.out.println("What's currently in 1st level cache");
System.out.println("---------------------------------");
for (Object o : session.getStatistics().getEntityKeys()) {
    EntityKey entityKey = (EntityKey) o;
    System.out.println(entityKey.getEntityName() + " -> " + entityKey.getIdentifier());
}
System.out.println("---------------------------------");
System.out.println("Ensure there are 3 project users");
System.out.println("---------------------------------");
checkArgument(session.createQuery("from ProjectUser").list().size() == 3);
System.out.println("---------------------------------");
System.out.println("Deleting all 3 project users");
System.out.println("---------------------------------");
checkArgument(session.createQuery("delete from ProjectUser").executeUpdate() == 3);
session.flush();
System.out.println("---------------------------------");
System.out.println("Latest state in 1st level cache");
System.out.println("---------------------------------");
for (Object o : session.getStatistics().getEntityKeys()) {
    EntityKey entityKey = (EntityKey) o;
    System.out.println(entityKey.getEntityName() + " -> " + entityKey.getIdentifier());
}

这是我看到的打印输出：-

---------------------------------
What's currently in 1st level cache
---------------------------------
testHibernate.domain.ProjectUser -> 2
testHibernate.domain.ProjectUser -> 1
testHibernate.domain.User -> 1
testHibernate.domain.ProjectUser -> 3
testHibernate.domain.User -> 3
testHibernate.domain.Project -> 1
testHibernate.domain.User -> 2
---------------------------------
Ensure there are 3 project users
---------------------------------
Hibernate: 
    select
        projectuse0_.projectUserId as projectU1_1_,
        projectuse0_.datetime as datetime2_1_,
        projectuse0_.projectId as projectI3_1_,
        projectuse0_.userId as userId4_1_ 
    from
        projectUser projectuse0_
[TRACE] [BasicExtractor] [extract:74] - Found [1] as column [projectU1_1_]
[TRACE] [BasicExtractor] [extract:74] - Found [2] as column [projectU1_1_]
[TRACE] [BasicExtractor] [extract:74] - Found [3] as column [projectU1_1_]
---------------------------------
Deleting all 3 project users
---------------------------------
Hibernate: 
    delete 
    from
        projectUser
---------------------------------
Latest state in 1st level cache
---------------------------------
testHibernate.domain.ProjectUser -> 2
testHibernate.domain.ProjectUser -> 1
testHibernate.domain.User -> 1
testHibernate.domain.ProjectUser -> 3
testHibernate.domain.User -> 3
testHibernate.domain.Project -> 1
testHibernate.domain.User -> 2

正如您所看到的，testHibernate.domain.ProjectUser实体仍然在一级缓存中徘徊，即使它们已经被删除。

我的问题是如何使用executeUpdate()方法从一级缓存中清除已删除的实体？有任何官方文件解释这个问题吗？

谢谢。

Answer 1

这是我的解决方案，但它确实不整洁。

BaseEntity只是我们所有实体的基类。

@PersistenceContext
transient EntityManager entityManager;
@SuppressWarnings("unchecked")
public void evict(Class<? extends BaseEntity> c)
{
    HibernateEntityManager hem = entityManager.unwrap(HibernateEntityManager.class);
    Session session = hem.getSession();
    Query query = session.createQuery("select o from " + c.getSimpleName() + " o where isObsolete = false AND isDeleted = false");
    List<? extends BaseEntity> entities = (List<? extends BaseEntity>) query.list();
    for (BaseEntity e : entities)
    {
        session.evict(e);
    }
}