Hibernate getCurrentSession()和openSession()的区别

通过getCurrentSession()创建的Session会绑定到当前线程上；openSession()不会。
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。

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