• 将 ISO8601 字符串转换为日期

    let isoDate = "2016-04-14T10:44:00+0000"
  

  let dateFormatter = DateFormatter()
  dateFormatter.locale = Locale(identifier: “en_US_POSIX”) // set locale to reliable US_POSIX
  dateFormatter.dateFormat = “yyyy-MM-dd’T’HH:mm:ssZ”
  let date = dateFormatter.date(from:isoDate)!

• 从日期获取年、月、日、小时的日期组件

    let calendar = Calendar.current
  

  let components = calendar.dateComponents([.year, .month, .day, .hour], from: date)

• 最后创建一个新Date对象并剥离分钟和秒

    let finalDate = calendar.date(from:components)
  

ISO8601DateFormatter还要考虑iOS 10 / macOS 10.12 中引入的便捷格式化程序：

let isoDate = "2016-04-14T10:44:00+0000"

let dateFormatter = ISO8601DateFormatter()
let date = dateFormatter.date(from:isoDate)!