list排序

最新推荐文章于 2024-03-04 21:48:59 发布

oliver341

最新推荐文章于 2024-03-04 21:48:59 发布

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本文介绍了一种利用commons-collections库中的BeanComparator、ComparableComparator及ComparatorChain等工具类来实现Java List集合排序的方法。具体展示了如何针对LogDTO对象的特定属性（如userDTO.userLoginUpdate）进行升序或降序排列。

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/**
	 * 
	 * 
	 * @Author: wang-junjie
	 * @Description: list排序
	 * @throws Exception
	 */
	@SuppressWarnings("unchecked")
	public static List<LogDTO> sortList(List<LogDTO> list, String propertyName, boolean isAsc) { 
        //借助commons-collections包的ComparatorUtils    
        //BeanComparator，ComparableComparator和ComparatorChain都是实现了Comparator这个接口    
        Comparator<?> mycmp = ComparableComparator.getInstance();       
        mycmp = ComparatorUtils.nullLowComparator(mycmp);  //允许null 
        if(isAsc){ 
        mycmp = ComparatorUtils.reversedComparator(mycmp); //逆序       
        } 
        Comparator<LogDTO> cmp = new BeanComparator(propertyName, mycmp);    
        Collections.sort(list, cmp);   
        return list; 
	} 


	@Transactional
	public JSONObject getIntimeLogInfo(Integer draw, Integer start, Integer length, String search,String startTime,String endTime) throws Exception {
		Map<String, Object> jsonMap = new HashMap<String, Object>();
		try {
			int count = 0;
			List<TbLog> listLogBean = this.logDAO.getIntimeLogInfo(start, length,startTime,endTime);
			// 数据传输对象处理
			List<LogDTO> listLogDTO = new ArrayList<LogDTO>();
			Iterator<TbLog> itrLogBean = listLogBean.iterator();
			while (itrLogBean.hasNext()) {
				TbLog objLogBean = (TbLog) itrLogBean.next();
				Integer logcount = this.logDAO.getLogCount(objLogBean.getUserLoginName(), startTime, endTime);
				System.out.println("--"+objLogBean.getUserLoginName()+"--"+objLogBean.getTbUser().getUserLoginName());
				objLogBean.setLogcount(logcount);
				listLogDTO.add(objLogBean.toDTO());
				
				count++;
			}
			//listLogDTO.;
			listLogDTO=sortList(listLogDTO,"userDTO.userLoginUpdate",true);//true按照userDTO.userLoginUpdate降序


			jsonMap.put("draw", draw);
			jsonMap.put("recordsTotal", count);
			jsonMap.put("recordsFiltered", count);
			jsonMap.put("data", listLogDTO);
		} catch (Exception e) {
			e.printStackTrace();
		}
		System.out.println(JSONObject.fromObject(jsonMap).toString(1));
		return JSONObject.fromObject(jsonMap);
	}