hql语句拼接的替换方式

　　　　　　　　　 String hql = "FROM Topic t WHERE t.forum=?  ";
		List<Object> parameters = new ArrayList<Object>();
		parameters.add(forum);
		if (viewType == 1) {
			hql += "AND t.type = ?";
			parameters.add(Topic.TYPE_BEST);
		}
		if(orderBy == 1){ //1表示只按最后更新时间排序 
			hql += "ORDER BY t.lastUpdateTime " + (asc?"ASC":"DESC");
		}else if(orderBy == 2){//2表示只按主题发表时间排序 
			hql += "ORDER BY t.postTime " + (asc?"ASC":"DESC");
		}else if(orderBy == 3){//3表示只按回复数量排序
			hql += "ORDER BY t.replyCount " + (asc?"ASC":"DESC");
		}else{ //0表示默认排序(置顶帖在前面, 并按最后更新时间降序排序) 
			hql += "ORDER BY (CASE t.type WHEN 2 THEN 2 ELSE 0 END) DESC, t.lastUpdateTime DESC";		
		}