Swift

Question

假设我有以下 JSON，我想将其解码为特定结构。我该怎么做

JSON:

{
 "fullName": "Federico Zanetello",
 "id": 123456,
 "twitter": "http://twitter.com/zntfdr",
 "results": ["mate","bate"]
}

解码结构

struct Response {
    let data: UserData,
    let results: [String]
}

UserData 结构

Struct UserData {
   let fullName: String,
   let id: Int,
   let twitter: String
}

我进行了研究，但找不到有效的解决方案。这是我到目前为止写的代码

struct UserData: Decodable {
    let fullName: String
    let id: Int
    let twitter: String
    
    enum CodingKeys: String, CodingKey {
        case fullName
        case id
        case twitter
    }
    
    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        self.fullName = try container.decode(String.self, forKey: .fullName)
        self.id = try container.decode(Int.self, forKey: .id)
        self.twitter = try container.decode(String.self, forKey: .twitter)
    }
}

struct Respone: Decodable{
    let data: UserData
    let results: [String]
}

let json = """
{
 "fullName": "Federico Zanetello",
 "id": 123456,
 "twitter": "http://twitter.com/zntfdr",
 "results": ["mate","bate"]
}
""".data(using: .utf8)! // our data in native (JSON) format
let myStruct = try JSONDecoder().decode(MetaData.self, from: json) // Decoding our data
print(myStruct)

我收到 KeynotFound 错误，因为 data 密钥不在 JSON 中。我该如何解决？

Answer 1

你只需要这个结构..数据在你的响应中没有作为键出现

// MARK: - User
struct User: Codable {
    let fullName: String
    let id: Int
    let twitter: String
    let results: [String]
}

像这样解码广告

let myStruct = try JSONDecoder().decode(User.self, from: json)

注意：如果您不执行任何额外操作，则不需要 init() 可编码函数。如果结构元素的名称相同，则不需要 CodingKeys

以下是如何将 UserData 用作带有 interface segregation

的单独对象

struct Response: UserData, Codable {
    let fullName: String
    let id: Int
    let twitter: String
    let results: [String]
}

protocol UserData {
    var fullName: String {get}
    var id: Int {get}
    var twitter: String{get}
}

  let myStruct = try JSONDecoder().decode(Response.self, from: json)

  let userData : UserData = myStruct 

  print(userData.fullName)

Answer 2

你可以这样做：

struct UserData: Decodable {
    let fullName: String
    let id: Int
    let twitter: String
}

struct Response: Decodable{
    let data: UserData
    let results: [String]
    
    enum CodingKeys : CodingKey {
        case results
    }
    
    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        results = try container.decode([String].self, forKey: .results)
        data = try decoder.singleValueContainer().decode(UserData.self)
    }
}

诀窍是在 Response 中使用自定义解码，像平常一样解码 results 后，得到 singleValueContainer。此容器将包含您 JSON 中的所有密钥，因此您可以使用此容器解码 UserData.

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