iOS開發之獲取當前日期的年月日及星期

大家是不是有時候有需要獲取當前時間的詳細日期

    NSDate *date = [NSDate date];
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    //獲取當前時間日期展示字符串 如：2019-05-23-13:58:59
    NSString *str = [formatter stringFromDate:date];

    //下面是單獨獲取每項的值
    NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDateComponents *comps = [[NSDateComponents alloc] init];
    NSInteger unitFlags = NSYearCalendarUnit |NSMonthCalendarUnit |NSDayCalendarUnit |NSWeekdayCalendarUnit |NSHourCalendarUnit |NSMinuteCalendarUnit |NSSecondCalendarUnit;
    comps = [calendar components:unitFlags fromDate:date];
    //星期 注意星期是從周日開始計算
    int week = [comps weekday];
    //年
    int year=[comps year];
    //月
    int month = [comps month];
    //日
    int day = [comps day];
    //時
    int hour = [comps hour];
    //分
    int minute = [comps minute];
    //秒
    int second = [comps second];