转换日期格式

Question

我有这样的日期格式.. 2017-06-05T15:51:56.996-07:00，我需要将其转换为yyyy-MM-dd hh:mm a。我正在使用下面的代码。

NSDateFormatter *format = [[NSDateFormatter alloc] init]; 
[format setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSSZZZZ"]; 
NSDate *date = [format dateFromString:dateString]; 
[format setDateFormat:@"yyyy-MM-dd hh:mm a"]; 
NSString* finalDateString = [format stringFromDate:date];` 

但我无法得到小时和上午/下午值的权利。我怎样才能得到这个？

Answer 1

NSString *dateStringWithTZ = @"2017-06-05T15:51:56.996-07:00"; 

// Create date object using the timezone from the input string. 
NSDateFormatter *dateFormatterWithTZ = [[NSDateFormatter alloc] init]; 
dateFormatterWithTZ.dateFormat = @"yyyy-MM-dd'T'HH:mm:ss.SSSZ"; 
NSDate *dateWithTZ = [dateFormatterWithTZ dateFromString:dateStringWithTZ]; 

// Cut off the timezone and create date object using GMT timezone. 
NSString *dateStringWithoutTZ = [dateStringWithTZ substringWithRange:NSMakeRange(0, 23)]; 
NSDateFormatter *dateFormatterWithoutTZ = [[NSDateFormatter alloc] init]; 
dateFormatterWithoutTZ.dateFormat = @"yyyy-MM-dd'T'HH:mm:ss.SSS"; 
dateFormatterWithoutTZ.timeZone = [NSTimeZone timeZoneWithAbbreviation:@"GMT"]; 
NSDate *dateWithoutTZ = [dateFormatterWithoutTZ dateFromString:dateStringWithoutTZ]; 

NSDateFormatter *format = [[NSDateFormatter alloc] init]; 
[format setDateFormat:@"yyyy-MM-dd hh:mm a"]; 
[format setLocale:[NSLocale localeWithLocaleIdentifier:@"en_US_POSIX"]]; 
format.timeZone = [NSTimeZone timeZoneWithAbbreviation:@"GMT"]; 
NSString* finalDateString = [format stringFromDate:dateWithoutTZ]; 

结果：2017年6月5日下午3点51

Answer 2

极品如下设置日历的地区：

-(NSString *)DateToString:(NSString *)getString 
{ 

    NSDateFormatter *format = [[NSDateFormatter alloc] init]; 
    [format setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSSZZZZ"]; 
    NSDate *date = [format dateFromString:getString]; 
    [format setDateFormat:@"yyyy-MM-dd hh:mm a"]; 
    [format setLocale:[NSLocale localeWithLocaleIdentifier:@"en_US_POSIX"]]; 
    NSString* finalDateString = [format stringFromDate:date]; 
    return finalDateString; 
}