public String add() throws Exception {
        Transaction tx = null;
        Session session = null;
        try {
            session= countryRegionDAO.getSessionFactory().openSession();
            tx=session.beginTransaction();
            
            CountryRegion region=new CountryRegion();
            region.setName(this.name);
            session.save(region);
            
            tx.commit();//-----------执行到这里抛出异常-------
            return "success";
        }
        catch(Exception e)  {
            if(tx != null) tx.rollback();
            //e.printStackTrace();
        } finally {
            session.close();
        }
        return "fail";
    }