休眠 session.save() 不反映在数据库中 [英] hibernate session.save() does not reflect in database

问题描述

根据我在hibernate中的理解(请确认)

According to my understanding in hibernate (please confirm)

1- 如果您通过 getSessionFactory().openSession() 获得它，您必须 session.close().
2- 如果您通过 getSessionFactory().getCurrentSession() 获得它，则无需 session.close().commit() 之后它会自动关闭.

1- You have to session.close() if you get it by getSessionFactory().openSession().
2- No need to session.close() if you get it by getSessionFactory().getCurrentSession(). It is automatically closed after commit().

3- @2 使用 getSessionFactory().getCurrentSession() 时，我们必须在活动事务中执行所有数据库活动，以便我们可以在结束.

3- @2 When using getSessionFactory().getCurrentSession(), we have to do all DB activities inside an active transaction so that we can commit() at the end.

4- Hibernate 将所有保存、更新和删除操作排入队列，并仅在 flush() 操作或 提交事务或关闭会话，其中发生这些操作.(根据 javadoc)

4- Hibernate en-queues all save, update, and delete operations and submits them to the database server only after a flush() operation or committing the transaction or closing of the session in which these operations occur.(as per javadoc)

从以上几点如果我考虑1 &4，那么下面的代码应该可以工作:

From the above points if I consider 1 & 4, then the following code should work:

Session session = HibernateUtil.getSessionFactory().openSession();  
AccountDetails ac = new AccountDetails();  
//perform set operations  
session.save(ac);  
session.close();  
System.out.println("new account stored.");

但是它不工作，即它运行平稳但没有反映(存储)在数据库中.为什么会这样?当我在事务中编写代码并提交时，它就会被存储.

BUT it is not working i.e. it runs smoothly but does not reflect(store) in database.Why this is so ? When I write the code inside a transaction and commit, then it is stored.

我想我错过了一个基本的东西.请澄清.

I think I am missing a basic thing. Please clarify.

推荐答案

当您使用 SessionFactory.openSession() 创建会话时，不会创建任何事务，因此您的操作是在事务上下文之外执行的.为了查看您的更改，您必须开始一个新事务，或者将您的操作作为正在进行的事务的一部分来执行.来自文档:

When you create session using SessionFactory.openSession(), no transaction is created, so your operations are executed outside of transaction context. In order to see your changes, you have to start a new transaction, or perform your operations as a part of ongoing transaction. From documentation:

一个典型的交易应该使用以下习惯用法:

A typical transaction should use the following idiom:

Session sess = factory.openSession();
 Transaction tx;
 try {
     tx = sess.beginTransaction();
     //do some work
     ...
     tx.commit();
 }
 catch (Exception e) {
     if (tx!=null) tx.rollback();
     throw e;
 }
 finally {
     sess.close();
 }

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