如何创建日期时间戳和格式为ISO 8601，RFC 3339，UTC时区? [英] How to create a date time stamp and format as ISO 8601, RFC 3339, UTC time zone?

问题描述

如何使用 ISO 8601 和 RFC 3339 ?

目标是一个看起来像这样的字符串:

The goal is a string that looks like this:

"2015-01-01T00:00:00.000Z"

格式:

• 年，月，日为"XXXX-XX-XX"
• 字母"T"作为分隔符
• 小时，分钟，秒和毫秒，如"XX:XX:XX.XXX".
• 字母"Z"作为零偏移的区域标记，又称UTC，GMT，祖鲁时间.

最佳情况:

• 快速，简单，简短的源代码.
• 无需使用任何其他框架，子项目，cocoapod，C代码等.

我已经搜索了StackOverflow，Google，Apple等，但没有找到Swift的答案.

I've searched StackOverflow, Google, Apple, etc. and haven't found a Swift answer to this.

看起来最有前途的类是 NSDate ， NSDateFormatter ，> c2> .

The classes that seem most promising are NSDate, NSDateFormatter, NSTimeZone.

相关问答:如何获得ISO 8601在iOS中约会?

这是到目前为止我想出的最好的方法:

Here's the best I've come up with so far:

var now = NSDate()
var formatter = NSDateFormatter()
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"
formatter.timeZone = NSTimeZone(forSecondsFromGMT: 0)
println(formatter.stringFromDate(now))

推荐答案

Swift 4•iOS 11.2.1或更高版本

extension ISO8601DateFormatter {
    convenience init(_ formatOptions: Options, timeZone: TimeZone = TimeZone(secondsFromGMT: 0)!) {
        self.init()
        self.formatOptions = formatOptions
        self.timeZone = timeZone
    }
}

---

extension Formatter {
    static let iso8601withFractionalSeconds = ISO8601DateFormatter([.withInternetDateTime, .withFractionalSeconds])
}

---

extension Date {
    var iso8601withFractionalSeconds: String { return Formatter.iso8601withFractionalSeconds.string(from: self) }
}

---

extension String {
    var iso8601withFractionalSeconds: Date? { return Formatter.iso8601withFractionalSeconds.date(from: self) }
}

---

用法:

---

Usage:

Date().description(with: .current)  //  Tuesday, February 5, 2019 at 10:35:01 PM Brasilia Summer Time"
let dateString = Date().iso8601withFractionalSeconds   //  "2019-02-06T00:35:01.746Z"

if let date = dateString.iso8601withFractionalSeconds {
    date.description(with: .current) // "Tuesday, February 5, 2019 at 10:35:01 PM Brasilia Summer Time"
    print(date.iso8601withFractionalSeconds)           //  "2019-02-06T00:35:01.746Z\n"
}

---

iOS 9•Swift 3或更高版本

extension Formatter {
    static let iso8601withFractionalSeconds: DateFormatter = {
        let formatter = DateFormatter()
        formatter.calendar = Calendar(identifier: .iso8601)
        formatter.locale = Locale(identifier: "en_US_POSIX")
        formatter.timeZone = TimeZone(secondsFromGMT: 0)
        formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSXXXXX"
        return formatter
    }()
}

---

可编码协议

如果在使用Codable时需要对这种格式进行编码和解码 协议，您可以创建自己的自定义日期编码/解码策略:

If you need to encode and decode this format when working with Codable protocol you can create your own custom date encoding/decoding strategies:

extension JSONDecoder.DateDecodingStrategy {
    static let iso8601withFractionalSeconds = custom {
        let container = try $0.singleValueContainer()
        let string = try container.decode(String.self)
        guard let date = Formatter.iso8601withFractionalSeconds.date(from: string) else {
            throw DecodingError.dataCorruptedError(in: container,
                  debugDescription: "Invalid date: " + string)
        }
        return date
    }
}

和编码策略

extension JSONEncoder.DateEncodingStrategy {
    static let iso8601withFractionalSeconds = custom {
        var container = $1.singleValueContainer()
        try container.encode(Formatter.iso8601withFractionalSeconds.string(from: $0))
    }
}

---

游乐场测试

---

Playground Testing

let dates = [Date()]   // ["Feb 8, 2019 at 9:48 PM"]

编码

let encoder = JSONEncoder()
encoder.dateEncodingStrategy = .iso8601withFractionalSeconds
let data = try! encoder.encode(dates)
print(String(data: data, encoding: .utf8)!)

解码

let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .iso8601withFractionalSeconds
let decodedDates = try! decoder.decode([Date].self, from: data)  // ["Feb 8, 2019 at 9:48 PM"]

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