ios - 无法在 Swift 4 中解码日期

Question

我目前正在尝试学习 Swift，但还没有走得很远，如果这是一个简单的问题，请原谅我；我已经为此工作了几个小时，但一直无法弄清楚。

我有一个名为 Person 的 Codable 类。在这个类中，我有一个名为 birthdate 的 Date 属性。所以它看起来像这样:

class Person : Codable {
    var birthdate: Date = Date()
    var firstName: String = ""
    var lastName: String = ""

    enum CodingKeys : String, CodingKey {
        case birthdate
        case firstName = "first_name"
        case lastName = "last_name"
    }
}

我正在尝试解码我​​的 JSON:

[
    {
        "address": "302 N. 5th St.",
        "base_64_image": null,
        "birthdate": "2009-05-06T18:56:38.367",
        "created": "2017-11-21T16:21:13",
        "emergency_contact": "",
        "emergency_contact_number": null,
        "father_cell_number": null,
        "father_home_number": null,
        "father_name": null,
        "first_name": "John",
        "gender": 1,
        "id": "d92fac59-66b9-49a5-9446-005babed617a",
        "image_uri": null,
        "is_inactive": false,
        "last_name": "Smith",
        "mother_cell_number": "1234567890",
        "mother_home_number": "",
        "mother_name": "His Mother",
        "nickname": null,
        "tenant_id": "9518352f-4855-4699-b0da-ecdc06470342",
        "updated": "2018-01-20T02:11:45.9025023"
    }
]

像这样:

// Fetch the data from the URL.
let headers: HTTPHeaders = [
    "Accept": "application/json"
]

Alamofire.request(url, headers: headers).responseJSON { response in
    if let data = response.data {
        let decoder = JSONDecoder()

        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
        decoder.dateDecodingStrategy = .formatted(dateFormatter)

        let people = try! decoder.decode(Array<Person>.self, from: data)
    }
}

但是，我总是得到同样的错误:

Fatal error: 'try!' expression unexpectedly raised an error: Swift.DecodingError.dataCorrupted(Swift.DecodingError.Context(codingPath: [Foundation.(_JSONKey in _12768CA107A31EF2DCE034FD75B541C9)(stringValue: "Index 47", intValue: Optional(47)), App.Person.CodingKeys.birthdate], debugDescription: "Date string does not match format expected by formatter.", underlyingError: nil))

(“索引 47”显然不准确，因为那是我的实时 [和私有(private)] 数据)。

如果我从 Person 类中取出 birthdate 属性，一切都会按预期进行。

几个小时以来，我一直在谷歌搜索和尝试新事物，但无论我怎样尝试，它仍然无法正常工作。这里有人可以帮我吗？

Answer 1

它看起来像你的生日之一:

"birthdate": "2009-05-06T18:56:38.367",

包含毫秒。您的日期格式字符串:

dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"

无法处理这个。您可以更改传入 JSON 中的 birthdate 字段，或将 dateFormat 字符串更改为:

dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS"

请注意，添加 .SSS 似乎会破坏非毫秒日期的格式化程序。我建议减少服务器端的毫秒数。

---

原回答如下:

我刚刚在 Playground 中尝试过，它似乎按预期工作:

class Person : Codable {
    var birthdate: Date = Date()
    var firstName: String = ""
    var lastName: String = ""

    enum CodingKeys : String, CodingKey {
        case birthdate
        case firstName = "first_name"
        case lastName = "last_name"
    }
}

var json: String = """
[
{
    "birthdate": "2009-05-06T18:56:38",
    "first_name": "John",
    "last_name": "Smith"
}
]
"""

let decoder = JSONDecoder()
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
decoder.dateDecodingStrategy = .formatted(dateFormatter)

let people = try! decoder.decode(Array<Person>.self, from: json.data(using: .utf8, allowLossyConversion: false)!)

people 现在是这样的:

{birthdate "May 6, 2009 at 6:56 PM", firstName "John", lastName "Smith"}

要么我的代码与您的代码略有不同，要么可能需要一组不同的示例数据。