ios 为 NSDateFormatter 设置日期格式

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时间:2020-08-30 19:39:00  来源:igfitidea点击:

setting date format for NSDateFormatter

iosdatensdateformatter

提问by Joey

I am trying to set the date format for something like "2011-04-21 03:31:37.310396". I think I'm not getting the fractional seconds right. I'm looking at http://unicode.org/reports/tr35/tr35-10.html#Date_Format_Patternsfor guidelines on how to specify it and I think my issue is in the format itself.

我正在尝试为“2011-04-21 03:31:37.310396”之类的内容设置日期格式。我想我没有得到正确的小数秒。我正在查看http://unicode.org/reports/tr35/tr35-10.html#Date_Format_Patterns以获取有关如何指定它的指南,我认为我的问题在于格式本身。

NSDateFormatter* dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ssSSSSSS";     
NSDate* serverDate = [dateFormatter dateFromString:stringFormOfDate];    

Help?

帮助?

回答by suprandr

try

尝试

NSDateFormatter* dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss.SSSSSS";     
NSDate* serverDate = [dateFormatter dateFromString:@"2011-04-21 03:31:37.310396"]; 

NSLog(@"%@", serverDate);

I guess you probably forgot the dot

我猜你可能忘了点

回答by malhal

As per Zaph's comment in the other answer: the maximum number of S is 3. Any more just produce zeros.

根据 Zaph 在另一个答案中的评论:S 的最大数量为 3。任何更多只会产生零。

E.g.

例如

dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss.SSSSSS"; // Last 3 'S' ignored.  

Then @"2011-04-21 03:31:37.311396" will produce 2011-04-21 03:31:37.311000

To maintain full microsecond precision try this magic:

为了保持完整的微秒精度,试试这个魔法:

-(NSDate *)_dateFromUtcString:(NSString *)utcString{
    if(!utcString){
        return nil;
    }
    static NSDateFormatter *df = nil;
    if (df == nil) {
        df = [[NSDateFormatter alloc] init];
        [df setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
        [df setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
    }

    NSArray* parts = [utcString componentsSeparatedByString:@"."];
    NSDate *utcDate = [df dateFromString:parts[0]];
    if(parts.count > 1){
        double microseconds = [parts[1] doubleValue];
        utcDate = [utcDate dateByAddingTimeInterval:microseconds / 1000000];
    }
    return utcDate;
}

Now an NSString "2011-04-21 03:31:37.310396" will parse fully to an NSDate 2011-04-21 03:31:37.310396

现在 NSString "2011-04-21 03:31:37.310396" 将完全解析为 NSDate 2011-04-21 03:31:37.310396