Spring的hibernateTemplate.preparQuery的问题

[RunningShadow_007]

prepareQuery作用是什么呢?百度了半天也没查到
查官方帮助文档Prepare the given Query object, applying cache settings and/or a transaction timeout. 解释的很潦草啊
executeWithNativeSession()这个方法和execute()相比具体的区别是什么呢?
官方文档Execute the action specified by the given action object within a native Session.只是说不需要打开新的session吗?

/**
	 * 分页查询
	 */
	@Override
	public List findPage(final String hql, final int maxResult,
			final int firstResult, final Object... paras) {
		List list = hibernateTemplate
				.executeFind(new HibernateCallback<List>() {

					@Override
					public List doInHibernate(Session session)
							throws HibernateException, SQLException {
						Query q = session.createQuery(hql);
						hibernateTemplate.prepareQuery(q);
						if (paras != null) {
							for (int i = 0; i < paras.length; i++) {
								q.setParameter(i, paras[i]);
							}
						}
						q.setFirstResult(firstResult);
						q.setMaxResults(maxResult);
						return q.list();
					}
				});
		return list;
	}

@Override
	public List findByHqlInCache(final String hql, final Object... paras) {
		return hibernateTemplate
				.executeWithNativeSession(new HibernateCallback<List>() {

					@Override
					public List doInHibernate(Session session)
							throws HibernateException, SQLException {
						Query q = session.createQuery(hql);
						hibernateTemplate.prepareQuery(q);
						if (paras != null) {
							for (int i = 0; i < paras.length; i++) {
								q.setParameter(i, paras[i]);
							}
						}
						return q.list();
					}
				});
	}