有一个List＜Date＞ ，现在有一个Date 时间，找到这个list 里面和时间最近的一个，进行返回

public static Date findNearestDate(List<Date> dateList, Date targetDate) {
        Date nearestDate = null;
        DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        for (Date date : dateList) {
            long diff = Math.abs(targetDate.getTime() - date.getTime());
            if (nearestDate == null || diff < Math.abs(nearestDate.getTime() - targetDate.getTime())) {
                nearestDate = date;
            }
        }

        return nearestDate;
    }