NSDate to NSString / NSString to NSDate

1. NSDate to NSString

//先建立你要的Format
NSDateFormatter*formatter =[[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss" ];

//看你的時區是什麼
[formatter setTimeZone:[NSTimeZone timeZoneWithName:@"Asia/Taipei"]];
NSString*stringFromDate =[formatter stringFromDate:myNSDateInstance];

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2. NSString to NSDate

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:@"Asia/Taipei"]];
NSDate *date = [dateFormatter dateFromString:@"2010-08-04 16:01:03"];