Session對象用於獲取與數據庫的物理連接。 Session對象是重量輕，設計了一個互動是需要與數據庫每次被實例化。持久化對象被保存，並通過一個Session對象中檢索。

會話中的對象不應該保持開放很長一段時間，因為他們通常不被線程安全的，他們應該被創建並根據需要摧毀他們。這次會議的主要功能是提供創建，讀取和刪除操作映射的實體類的實例。實例中可能存在以下三種狀態之一在給定時間點：

• 短暫性: 持久化類的未與會話相關聯，並在數據庫中冇有代表性，冇有標識值的新實例被Hibernate認為是暫時的。

• 持久性: 可以做一個瞬態的實例持久化通過將它與一個會話相關聯。持久性實例都有一個表示在數據庫中，一個標識符值，與會話相關聯。

• 獨立性: 一旦我們關閉Hibernate的Session，持久化實例將成為一個分離的實例。

一個Session實例是可序列化的，如果它的持久化類是可序列化的。一個典型的事務應該使用下麵的語句：

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

如果Session拋出異常，事務必須回滾，會話必須被丟棄。

Session 接口方法:

Session接口提供多個方法，但這裡列出的隻有少數重要的方法，這些方法我們在本教學中會使用。您可以查看Hibernate文檔Session和SessionFactory相關方法的完整列表。

S.N.	會話的方法和說明
1	Transaction beginTransaction()  Begin a unit of work and return the associated Transaction object.
2	void cancelQuery()  Cancel the execution of the current query.
3	void clear()  Completely clear the session.
4	Connection close()  End the session by releasing the JDBC connection and cleaning up.
5	Criteria createCriteria(Class persistentClass)  Create a new Criteria instance, for the given entity class, or a superclass of an entity class.
6	Criteria createCriteria(String entityName)  Create a new Criteria instance, for the given entity name.
7	Serializable getIdentifier(Object object)  Return the identifier value of the given entity as associated with this session.
8	Query createFilter(Object collection, String queryString)  Create a new instance of Query for the given collection and filter string.
9	Query createQuery(String queryString)  Create a new instance of Query for the given HQL query string.
10	SQLQuery createSQLQuery(String queryString)  Create a new instance of SQLQuery for the given SQL query string.
11	void delete(Object object)  Remove a persistent instance from the datastore.
12	void delete(String entityName, Object object)  Remove a persistent instance from the datastore.
13	Session get(String entityName, Serializable id)  Return the persistent instance of the given named entity with the given identifier, or null if there is no such persistent instance.
14	SessionFactory getSessionFactory()  Get the session factory which created this session.
15	void refresh(Object object)  Re-read the state of the given instance from the underlying database.
16	Transaction getTransaction()  Get the Transaction instance associated with this session.
17	boolean isConnected()  Check if the session is currently connected.
18	boolean isDirty()  Does this session contain any changes which must be synchronized with the database?
19	boolean isOpen()  Check if the session is still open.
20	Serializable save(Object object)  Persist the given transient instance, first assigning a generated identifier.
21	void saveOrUpdate(Object object)  Either save(Object) or update(Object) the given instance.
22	void update(Object object)  Update the persistent instance with the identifier of the given detached instance.
23	void update(String entityName, Object object)  Update the persistent instance with the identifier of the given detached instance.