hibernate Closed Instance Analysis of Session

The main research in this article is the closure of hibernate on session, as follows.

 Student student = new Student(); student.setName("Jan"); student.setAge("22"); student.setAddress("Zhaoqing City, Guangdong Province"); Session session =HibernateUtil.getSessionFactory().getCurrentSession(); session.beginTransaction(); session.save(student); session.flush(); session.getTransaction().commit();

1. What is the difference between getCurrentSession() and openSession()?

• The session created with getCurrentSession() will be bound to the current thread, while the session created with openSession() will not be
• The session created with getCurrentSession() will be automatically closed when commit or rollback, while the session created with openSession() must be closed manually.
  

2. To use getCurrentSession() you need to add the following configuration to the hibernate.cfg.xml file:

• If you are using a local transaction (jdbc transaction)
  

<property name="hibernate.current_session_context_class">thread</property>

• If you are using a global transaction (jta transaction)
  

<property name="hibernate.current_session_context_class">jta</property>

What is the difference and correlation between openSession() and getCurrentSession() ?

When SessionFactory is started, Hibernate will create the corresponding CurrentSessionContext according to the configuration. When getCurrentSession() is called, the actual method to be executed is CurrentSessionContext.currentSession() . When currentSession() is executed, if the current Session is empty, currentSession will call openSession of SessionFactory. So getCurrentSession() is a better way to get Session for Java EE.

Many times session is close(); the reason is that you set it in hibernate.cfg.xml

 <property name="hibernate.current_session_context_class">thread</property>

The system closes the session after commit(); after executing it. At this time, if you manually close the session, it will of course indicate an error.

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