获取当前时间、年份、月份、日期等

- (void)getCurrentDate {
//    获得时间对象
//    NSDate *date = [NSDate date];
//    // 获得系统的时区
//    NSTimeZone *zone = [NSTimeZone systemTimeZone];
//    // 以秒为单位返回当前时间与系统格林尼治时间的差
//    NSTimeInterval time = [zone secondsFromGMTForDate:date];
//    // 然后把差的时间加上,就是当前系统准确的时间
//    NSDate *nowDate = [date dateByAddingTimeInterval:time];
//    NSLog(@"now date is: %@", nowDate);
    
    // 获取当前时间
    NSDate *now = [NSDate date];
    // NSLog(@"now date is: %@", now);

    NSCalendar *calendar = [NSCalendar currentCalendar];
    unsigned unitFlags = NSCalendarUnitYear | NSCalendarUnitMonth |  NSCalendarUnitDay | NSCalendarUnitHour |  NSCalendarUnitMinute | NSCalendarUnitSecond | NSCalendarUnitWeekday;
        NSDateComponents *dateComponent = [calendar components:unitFlags fromDate:now];
    NSLog(@"dateComponent is :%@", dateComponent);
    
    NSInteger year = [dateComponent year];
    NSInteger month = [dateComponent month];
    NSInteger day = [dateComponent day];
    NSInteger hour = [dateComponent hour];
    NSInteger minute = [dateComponent minute];
    NSInteger second = [dateComponent second];
    NSInteger weekday = [dateComponent weekday];
    
    NSLog(@"year is: %ld", (long)year);
    NSLog(@"month is: %ld", (long)month);
    NSLog(@"day is: %ld", (long)day);
    NSLog(@"hour is: %ld", (long)hour);
    NSLog(@"minute is: %ld", (long)minute);
    NSLog(@"second is: %ld", (long)second);
    NSLog(@"weekday is: %ld", (long)weekday);
}