对Save方法和Persist方法仍然有疑问，垦盼指点

引用

persist() is well defined. It makes a transient instance persistent. However, it doesn't guarantee that the identifier value will be assigned to the persistent instance immediately, the assignment might happen at flush time. The spec doesn't say that, which is the problem I have with persist().

persist() also guarantees that it will not execute an INSERT statement if it is called outside of transaction boundaries. This is useful in long-running conversations with an extended Session/persistence context.

A method like persist() is required.

save() does not guarantee the same, it returns an identifier, and if an INSERT has to be executed to get the identifier (e.g. "identity" generator, not "sequence"), this INSERT happens immediately, no matter if you are inside or outside of a transaction. This is not good in a long-running conversation with an extended Session/persistence context.

[ Show » ] Christian Bauer - 12/Oct/06 08:04 AM In case anybody finds this thread... persist() is well defined. It makes a transient instance persistent. However, it doesn't guarantee that the identifier value will be assigned to the persistent instance immediately, the assignment might happen at flush time. The spec doesn't say that, which is the problem I have with persist(). persist() also guarantees that it will not execute an INSERT statement if it is called outside of transaction boundaries. This is useful in long-running conversations with an extended Session/persistence context. A method like persist() is required. save() does not guarantee the same, it returns an identifier, and if an INSERT has to be executed to get the identifier (e.g. "identity" generator, not "sequence"), this INSERT happens immediately, no matter if you are inside or outside of a transaction. This is not good in a long-running conversation with an extended Session/persistence context.

引用

persist"保证"，当它在一个transaction外部被调用的时候并不触发一个Sql Insert，这个功能是很有用的，
save"不保证"第2条，它要返回标识符，所以它会立即执行Sql insert，不管是不是在transaction内部还是外部

    Session session1 = HibernateUtil.getSessionFactory().openSession();

            Transaction tx1 = session1.beginTransaction();

            tx1.commit();

            Item item = new Item();

            item.setItemId("101");

            item.setItemName("football");

            session1.save(item); //在事务外执行save方法

            session1.close();

            HibernateUtil.shutdown();