ISO8601DateFormatter不解析ISO日期字符串

Question

我正在尝试解析这个问题

2017-01-23T10:12:31.484Z

使用ISO8601DateFormatter提供的本机类iOS 10但始终失败.如果字符串不包含毫秒,Date则创建对象时没有问题.

我试过这个和许多options组合,但总是失败...

let formatter = ISO8601DateFormatter()
formatter.timeZone = TimeZone(secondsFromGMT: 0)
formatter.formatOptions = [.withInternetDateTime, .withDashSeparatorInDate, .withColonSeparatorInTime, .withColonSeparatorInTimeZone, .withFullTime]

任何的想法？谢谢!

Answer 1

在macOS之前,10.13/iOS 11 ISO8601DateFormatter不支持日期字符串,包括毫秒.

解决方法是使用正则表达式删除毫秒部分.

let isoDateString = "2017-01-23T10:12:31.484Z"
let trimmedIsoString = isoDateString.replacingOccurrences(of: "\\.\\d+", with: "", options: .regularExpression)
let formatter = ISO8601DateFormatter()
let date = formatter.date(from: trimmedIsoString)

在macOS 10.13+/iOS 11+中,添加了一个新选项以支持小数秒:

static var withFractionalSeconds: ISO8601DateFormatter.Options { get }

let isoDateString = "2017-01-23T10:12:31.484Z"
let formatter = ISO8601DateFormatter()
formatter.formatOptions =  [.withInternetDateTime, .withFractionalSeconds]
let date = formatter.date(from: isoDateString)

Answer 2

对于尚未准备好使用 iOS 11 的人，您始终可以创建自己的格式化程序来处理毫秒，例如：

extension DateFormatter {
    static var iSO8601DateWithMillisec: DateFormatter {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
        return dateFormatter
    }
}

用法：

let formater = DateFormatter.iSO8601DateWithMillisec
let date = formater.date(from: "2017-01-23T10:12:31.484Z")!
print(date) // output: 2017-01-23 10:12:31 +0000

它比编写正则表达式来从输入字符串中去除毫秒要稍微优雅一些​​。

Answer 3

也许这将有助于解码略有不同的格式：

extension JSONDecoder {
    enum DateDecodeError: String, Error {
        case invalidDate
    }

    static var bestDateAttemptDecoder: JSONDecoder {
        let decoder = JSONDecoder()
        decoder.dateDecodingStrategy = .custom({ (decoder) -> Date in
            let container = try decoder.singleValueContainer()
            if let dateSecs = try? container.decode(Double.self) {
                return Date(timeIntervalSince1970: dateSecs)
            }

            if let dateSecs = try? container.decode(UInt.self) {
                return Date(timeIntervalSince1970: TimeInterval(dateSecs))
            }

            let dateStr = try container.decode(String.self)
            let isoFormatter = ISO8601DateFormatter()
            isoFormatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
            if let date = isoFormatter.date(from: dateStr) {
                return date
            }

            isoFormatter.formatOptions = [.withInternetDateTime ]
            if let date = isoFormatter.date(from: dateStr) {
                return date
            }

            log.warning("Cannot decode date");
            throw DateDecodeError.invalidDate
        })

        return decoder
    }
}

来自： https: //gist.github.com/th3m477/442a0d1da6354dd3b84e3b71df5dca6a