Hibernate getCurrentSession()和openSession()的区别

Posted 2020-08-13

1. 通过getCurrentSession()创建的Session会绑定到当前线程上；openSession()不会。
2. 通过getCurrentSession()获取Session，首先是从当前上下文中寻找旧的Session,如果没有，则创建新的Session；而openSession()是每次都创建新的Session。
3. getCurrentSession()创建的Session在事物提交时自动关闭；openSession()创建的Session需要手动关闭。

    1     @Test
    2     public void testTeacherSave() {
    3     
    4         Teacher t = new Teacher();
    5         
    6         t.setName("t1");
    7         t.setTitle("middle");
    8         t.setBirthDate(new Date());
    9         
   10         Session session = sessionFactory.openSession();
   11         //Session session = sessionFactory.getCurrentSession();
   12         
   13         session.beginTransaction();
   14         session.save(t);
   15         
   16         Session session2 = sessionFactory.getCurrentSession();
   17         
   18         System.out.println(session == session2);
   19         
   20         session.getTransaction().commit();
   21         
   22         Session session3 = sessionFactory.getCurrentSession();
   23         
   24         System.out.println(session == session3);
   25         
   26     }
   
   

   输出：Hibernate:
       insert
       into
           Teacher
           (birthDate, gender, good, name, title)
       values
           (?, ?, ?, ?, ?)
   false
   false

    1 @Test
    2     public void testTeacherSave() {
    3     
    4         Teacher t = new Teacher();
    5         
    6         t.setName("t1");
    7         t.setTitle("middle");
    8         t.setBirthDate(new Date());
    9         
   10         //Session session = sessionFactory.openSession();
   11         Session session = sessionFactory.getCurrentSession();
   12         
   13         session.beginTransaction();
   14         session.save(t);
   15         
   16         Session session2 = sessionFactory.getCurrentSession();
   17         
   18         System.out.println(session == session2);
   19         
   20         session.getTransaction().commit();
   21         
   22         Session session3 = sessionFactory.getCurrentSession();
   23         
   24         System.out.println(session == session3);
   25         
   26     }

   输出：Hibernate:
       insert
       into
           Teacher
           (birthDate, gender, good, name, title)
       values
           (?, ?, ?, ?, ?)
   true
   false