休眠:flush() 和 commit() [英] Hibernate: flush() and commit()

问题描述

单独调用 org.hibernate.Session.flush() 是个好习惯吗?

Is it good practice to call org.hibernate.Session.flush() separately?

如org.hibernate.Session 文档所述，

必须在工作单元结束时调用，在提交事务和关闭会话之前(取决于刷新模式，Transaction.commit() 调用此方法).

Must be called at the end of a unit of work, before commiting the transaction and closing the session (depending on flush-mode, Transaction.commit() calls this method).

如果 org.hibernate.Transaction.commit() 已经会调用 flush()，你能不能明确地解释一下调用它的目的?

Could you explain the purpose of calling flush() explicitely if org.hibernate.Transaction.commit() will do it already?

推荐答案

在 Hibernate Manual 中可以看到这个例子

In the Hibernate Manual you can see this example

Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();

for (int i = 0; i < 100000; i++) {
    Customer customer = new Customer(...);
    session.save(customer);
    if (i % 20 == 0) { // 20, same as the JDBC batch size
        // flush a batch of inserts and release memory:
        session.flush();
        session.clear();
    }
}

tx.commit();
session.close();

如果没有调用flush方法，你的一级缓存会抛出一个OutOfMemoryException

Without the call to the flush method, your first-level cache would throw an OutOfMemoryException

你也可以看看这个关于脸红的帖子

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