Hibernate openSession vs getCurrentSession

Question

I have some questions about using Hibernate in JSP web application    What should be the value for hibernate current session context class  Then  which of the following statements should be used  And why    Session s   HibernateUtil getSessionFactory   openSession     Session s   HibernateUtil getSessionFactory   getCurrentSession    Lastly  which one is better  one session per web app  or  one session per request

User · Answer

If we talk about SessionFactory openSession     It always creates a new Session object  You need to explicitly flush and close session objects  In single threaded environment it is slower than getCurrentSession    You do not need to configure any property to call this method    And If we talk about SessionFactory getCurrentSession     It creates a new Session if not exists  else uses same session which is in current hibernate context  You do not need to flush and close session objects  it will be automatically taken care by Hibernate internally  In single threaded environment it is faster than openSession    You need to configure additional property   hibernate current session context class  to call getCurrentSession   method  otherwise it will throw an exception

User · Answer

SessionFactory    One SessionFactory per application per DataBase     e g    if you use 3 DataBase s in our application   you need to create sessionFactory object per each DB   totally you need to create 3 sessionFactorys   or else if you have only one DataBase One sessionfactory is enough     Session   One session for one request-response cycle   you can open session when request came and you can close session after completion of request process   Note -Don t use one session for web application

User · Answer

As explained in this forum post  1 and 2 are related  If you set hibernate current session context class to thread and then implement something like a servlet filter that opens the session - then you can access that session anywhere else by using the SessionFactory getCurrentSession     SessionFactory openSession   always opens a new session that you have to close once you are done with the operations  SessionFactory getCurrentSession   returns a session bound to a context - you don t need to close this   If you are using Spring or EJBs to manage transactions you can configure them to open   close sessions along with the transactions   You should never use one session per web app - session is not a thread safe object - cannot be shared by multiple threads  You should always use  one session per request  or  one session per transaction

User · Answer

openSession  When you call SessionFactory openSession  it always creates a new Session object and give it to you   You need to explicitly flush and close these session objects    As session objects are not thread safe  you need to create one session object per request in multi-threaded environment and one session per request in web applications too   getCurrentSession  When you call SessionFactory getCurrentSession  it will provide you session object which is in hibernate context and managed by hibernate internally  It is bound to transaction scope   When you call SessionFactory getCurrentSession  it creates a new Session if it does not exist  otherwise use same session which is in current hibernate context  It automatically flushes and closes session when transaction ends  so you do not need to do it externally   If you are using hibernate in single-threaded environment   you can use getCurrentSession  as it is faster in performance as compared to creating a new session each time   You need to add following property to hibernate cfg xml to use getCurrentSession method    lt session-factory gt       lt  --  Put other elements here -- gt       lt property name  hibernate current session context class  gt            thread      lt  property gt   lt  session-factory gt

User · Answer

---------------------- ---------------------------------------------------------------------------- -----------------------------------------------------------------------------------------------------    Parameter                                             openSession                                                                            getCurrentSession                                             ---------------------- ---------------------------------------------------------------------------- -----------------------------------------------------------------------------------------------------    Session  creation      Always open new session                                                      It opens a new Session if not exists   else use same session which is in current hibernate context     ---------------------- ---------------------------------------------------------------------------- -----------------------------------------------------------------------------------------------------    Session close          Need to close the session object once all the database operations are done   No need to close the session  Once the session factory is closed  this session object is closed        ---------------------- ---------------------------------------------------------------------------- -----------------------------------------------------------------------------------------------------    Flush and close        Need to explicity flush and close session objects                            No need to flush and close sessions   since it is automatically taken by hibernate internally          ---------------------- ---------------------------------------------------------------------------- -----------------------------------------------------------------------------------------------------    Performance            In single threaded environment   it is slower than getCurrentSession         In single threaded environment   it is faster than openSession                                         ---------------------- ---------------------------------------------------------------------------- -----------------------------------------------------------------------------------------------------    Configuration          No need to configure any property to call this method                        Need to configure additional property                                                                                                                                                                         lt property name   hibernate current session context class   gt thread lt  property gt                           ---------------------- ---------------------------------------------------------------------------- -----------------------------------------------------------------------------------------------------

[java] Hibernate openSession() vs getCurrentSession()

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