如何正确关闭和打开休眠会话？

    Transaction tx = session.beginTransaction();    try {        for (int i = 0; i < mesages.size(); i++) { Message message = messages.get(i); session.save(message); if (i % 75 == 0) {      // flush a batch of inserts and release memory:     session.flush();     session.clear(); }        }        tx.commit();    }catch (Exception e) {        // TODO Auto-generated catch block        e.printStackTrace();        tx.rollBack();    }finally{        session.close();    }}