hibernate连接oracle查询语句的有关问题。查询方法连接sql server没有有关问题。可是数据库换成oracle查不到结果

public User checkUser(final User user){
        return (User) getHibernateTemplate().execute(new HibernateCallback() {
            public Object doInHibernate(Session session) throws HibernateException,
                    SQLException {
                // TODO Auto-generated method stub
                Query query = session.createQuery("from User where username = ? and password = ?");
                query.setString(0, user.getUsername());
                query.setString(1, user.getPassword());
                return query.uniqueResult();
            }
        });
    }