NSDate *nowDate = [NSDate date];
        NSString *strTenHourMeasureTime = [BDKNSUserDefaults fetchTenHourMeasureTime];
        NSDateFormatter *formatter = [[NSDateFormatter alloc]init];
        [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
        //相加（加了48*60*60秒）
        NSDate *dateTenHourMeasureTime = [formatter dateFromString:strTenHourMeasureTime];
        NSDate *date = [NSDate dateWithTimeInterval:48*60*60 sinceDate:dateTenHourMeasureTime];
        //两个时间相减得到秒数
        NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
        unsigned int unitFlags = NSSecondCalendarUnit;//年、月、日、时、分、秒、周等等都可以
        NSDateComponents *comps = [gregorian components:unitFlags fromDate:nowDate toDate:date options:0];
        NSInteger second = [comps second];