Swift JSON 序列化类型不匹配

Question

目前正在纠结如何使用Decodable。我已经对遇到的错误进行了一些谷歌搜索，但我仍然相信我构建结构的方式不正确，但对我来说似乎很有意义。

我也试过使用选项

在我最后发布的错误中，我对 Double 类型的引用感到困惑。因为我没有任何类型或任何使用双精度的响应。

（我还可以使用旧的 swift 方法将数据转换为字典 - [String : Any] 来序列化 json 响应。但我想使用modern/updated 方法。）

JSON 回应

    {"NEWS":
  [
    {
      "DATE":"2018-10-13T03:56:06+1000",
      "SOURCE":"smh.com.au",
      "BLURB":"Assistant Treasurer Stuart Robert says he has repaid ,975 of \"excess usage charges\" in home internet bills footed by taxpayers.",
      "ID":102347,
      "TITLE":"Stuart Robert pays back ,000 in excessive home internet charges"
    },
    {
      "DATE":"2018-10-12T18:00:38+1000",
      "SOURCE":"itwire.com",
      "BLURB":"The CVC costs set by the NBN Co make it very difficult for ISPs to offer gigabit connections to more than a select band of customers who are willing to sign up in numbers and pay slightly more than other speed tiers, according to one ISP who caters to this type of consumer.",
      "ID":102343,
      "TITLE":"NBN gigabit connections will remain mostly a pipe dream"},
    {
      "DATE":"2018-10-12T09:48:43+1000",
      "SOURCE":"computerworld.com.au",
      "BLURB":"The Department of Home Affairs has rejects calls to include independent judicial oversight of the decision to issue Technical Assistance Notices and Technical Capability Notices as part of proposed legislation intended to tackle police agencies’ inability to access encrypted communications services.",
      "ID":102342,
      "TITLE":"Home Affairs rejects calls for additional safeguards in ‘spyware’ law"
    },
    {
    "DATE":"2018-10-11T12:16:05+1000",
    "SOURCE":"itnews.com.au",
    "BLURB":"NBN Co is hoping to “speed up” building works on the fibre-to-the-curb (FTTC) portion of its network as it tries to make up lost ground.",
    "ID":102334,
    "TITLE":"NBN Co says fibre-to-the-curb build is more complex that it hoped"
    },
  ]
}

代码

struct Root: Decodable {
    let news: [News]?

    enum CodingKeys: String, CodingKey {
        case news = "NEWS"
    }

}

struct News: Decodable {
    let date: Date
    let source, blurb: String
    let id: Int
    let title: String

    enum CodingKeys: String, CodingKey {
        case date = "DATE"
        case source = "SOURCE"
        case blurb = "BLURB"
        case id = "ID"
        case title = "TITLE"
    }
}

序列化

URLSession.shared.dataTask(with: url) { (data, response, err) in  
guard let dataStr = data else {
            return
        }
do {
    let root = try JSONDecoder().decode(Root.self, from: dataStr) //error is caught here
    guard let r = root else { return }
    print(r.news)
} catch let err {
    print("JSON Error - \(err)")
}
}.resume()

错误

error serializing json typeMismatch(Swift.Double, Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "NEWS", intValue: nil), _JSONKey(stringValue: "Index 0", intValue: 0), CodingKeys(stringValue: "DATE", intValue: nil)], debugDescription: "Expected to decode Double but found a string/data instead.", underlyingError: nil))

Answer 1

这是因为日期的默认编码策略是双精度（从纪元开始的秒数）。您可以将默认策略更改为 iso8061 或任何自定义策略。例如，您可以像这样在解码器中设置日期格式化程序：

let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .iso8601

Answer 2

将 JSON 放入 Quicktype 会给我一个额外的逗号错误。除非 json 文件有更多节点？所以首先要确定这一点。乍一看，我可能是错的，但我认为您必须将 DATE 格式化为完全匹配。

Swift JSON 序列化类型不匹配

Swift JSON Serialization typeMismatch

serialization

json

struct

swift

decodable