一、

List<DataStatistic> statAllList = new ArrayList<DataStatistic>();
Collections.sort(statAllList, new Comparator<DataStatistic>() {
	@Override
	public int compare(DataStatistic o1, DataStatistic o2) {
		// 按照时间进行降序排列
		DateFormat timformat = new SimpleDateFormat("yyyy-MM-dd");//日期格式
		try {
		Date date0 = timformat.parse(o1.getStatisticTime());
		Date date1 = timformat.parse(o2.getStatisticTime());
		if (date0.getTime() > date1.getTime()) {
			return -1;
		}
		if (o1.getStatisticTime() == o2.getStatisticTime()) {
			return 0;
		}
	 } catch (ParseException e) {
			logger.error("日期转换异常", e);
			e.printStackTrace();
		   }
		return 1;
	}
});

Collections.sort(statAllList,new Comparator<DataStatistic>(){
   @Override
     public int compare(DataStatistic o1, DataStatistic o2) {
          return o2.getStatisticTime().compareTo(o1.getStatisticTime());
     }
});

二、

List<Object> itemlist = new ArrayList<Object>();

Collections.sort(itemlist,new Comparator<Object>(){
	Map<String, Object> map01 = new HashMap<String, Object>();
    Map<String, Object> map02 = new HashMap<String, Object>();
    @Override
     public int compare(Object o1, Object o2) {
    	 map01 = (Map<String, Object>) o1;
    	 map02 = (Map<String, Object>) o2;
    	 String value1 = (String) map01.get("endTime");
    	 String value2 = (String) map02.get("endTime");
         return value2.compareTo(value1);
     } 
 });