我正在尝试格式化时间戳，但返回了错误的值。lettimestampDouble:Double=1455970380471lettimestamp=NSDate(timeIntervalSince1970:timestampDouble)letformattedTimestamp=NSDateFormatter.localizedStringFromDate(timestamp,dateStyle:.MediumStyle,timeStyle:.ShortStyle)formattedTimestamp返回Jun22,48115,8:49AM而不是正确的时间戳Feb20,2016,11: