NSDateFormatter美国时间格式转换

//日期处理
var dateFormatter = NSDateFormatter()
dateFormatter.dateStyle = NSDateFormatterStyle.MediumStyle
dateFormatter.timeStyle = NSDateFormatterStyle.MediumStyle
dateFormatter.locale = NSLocale(localeIdentifier: "en_US") // zh_CN  en_US

var today:NSDate = NSDate()
var dateString = dateFormatter.stringFromDate(today)
println(dateString)//打印结果：Aug 30, 2015, 10:57:33 AM

//endDate为此种时间格式字符串（Aug 30, 2015, 10:57:33 AM）
let ndate = dateFormatter.dateFromString(endDate!)!
var endDateString = ndate.description
var ns2=(endDateString as NSString).substringToIndex(16)
println(ns2)//打印结果：2015-07-30 16:00