如你所说，你应该使用 NSDateFormatter 为你的期望的格式。希望这对你有帮助。

As you say, you should use NSDateFormatter for your desired format. Hope this will help you.

let date = NSDate()
let formatter = NSDateFormatter()
formatter.dateFormat = "hh:mm a"
let time = formatter.stringFromDate(date)

有关日期格式化程序的详细信息，请参阅 NSDateFormatter

For more information about date formatter see NSDateFormatter