java 获取两个时间相差的天数

    public static int getIntervalDays(Date startTime, Date endTime) {
        if (startTime != null && endTime != null) {
            long et = endTime.getTime();
            long st = startTime.getTime();
            long l = et - st;
            long dayCount = l / (24 * 60 * 60 * 1000);
            return new Integer((int) (dayCount + 1));
        }
        return -10;
    }