How to convert MySQL datetime to NSDate?

问题

MySQL returns this datetime: 2014-05-07T16:58:44.000Z

How, with what datetime format I can create NSDate?

I far as I found this, but it does not work:

NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateFormat:@"yyyy'-'MM'-'dd'T'HH':'mm':'ss'Z'"];
NSDate *date = [df dateFromString: valueStr];

回答1:

Your format string is close, but you want to specify the milliseconds with SSS, too:

[df setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSSX"];

Also, the Z in your date string stands for "Zulu" (i.e. GMT/UTC), so your dateFormat should use Z or X without quotes so that it correctly parses the string's time zone. Also, if you're building strings from dates, make sure to set your time zone accordingly. You also want to set your locale, too:

NSLocale *enUSPOSIXLocale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
formatter.locale = enUSPOSIXLocale;
formatter.dateFormat = @"yyyy-MM-dd'T'HH:mm:ss.SSSX";
formatter.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:0];

See Technical Q&A QA1480 for more information.

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You can also use the newer NSISO8601DateFormatter, which gets you out of some of those weeds:

NSISO8601DateFormatter *formatter = [[NSISO8601DateFormatter alloc] init];
formatter.formatOptions = NSISO8601DateFormatWithFullDate | NSISO8601DateFormatWithFullTime | NSISO8601DateFormatWithFractionalSeconds;

来源：https://stackoverflow.com/questions/23527315/how-to-convert-mysql-datetime-to-nsdate