Java查找Map中的日期时间里当前时间最远

	/**
	 * 查找日期时间 最小的 index
	 * @param map
	 * @return
	 */
	public static Integer minSectionId(Map<Integer, String> map) {
		Integer sectionId = 1;
		Calendar minDate = Calendar.getInstance();
		minDate.setTime(stringToDate(map.get(1)));

		for (Integer i = 1; i <= map.size(); i++) {
			Calendar date = Calendar.getInstance();
			date.setTime(stringToDate(map.get(i)));
			if (date.compareTo(minDate) <= 0) {
				minDate = date;
				sectionId = i;
			}
		}
		return sectionId;
	}