HQL 随机抽取数据，无重复

几天晚上在做那个在线教学，要随机抽取选择题和判断题，实现了，代码贴出来备用

	public HashSet querySelectQues(){
		try {
                       //set放结果，无重复
			HashSet<Examques> result = new HashSet<Examques>(); 
//查询出所有选择题（因为所有的题在一起放着）			
List<Examques> list=getHibernateTemplate().find("from Examques as examques where examques.examquesStyle = 1");

			int maxSize = list.size();
//只有当题的数目符合时在跳出循环
			while (true) {

				int randNumber = (int) (Math.random() * maxSize + 1) - 1;
				result.add(list.get(randNumber));
//将题的数目设成全局的				
if (result.size() >= ExamOnlineConstant.selectQuesNum) {
					break;
				} 
			}
			return result;
		}
		catch (RuntimeException re) {
			log.error("find by property name failed", re);
			throw re;
		}
	}