两个日期相差的天数

// 两个日期相差的天数
    public int differDays(String startDateString, String endDateString)
            throws ParseException {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Date start = sdf.parse(startDateString);
        Date end = sdf.parse(endDateString);
        int differ = (int) ((end.getTime() - start.getTime()) / (3600 * 24 * 1000));
        return differ;
    }