ios - swift 对象映射器 : How to parse array inside of an array

Question

这是我的 JSON 响应:

[
    [
        {
            "id": 22,
            "request_id": "rqst5c12fc9e856ae1.06631647",
            "business_name": "Code Viable",
            "business_email": "code@viable.com",
            "title": "Apache Load/Ubuntu",
        }
    ],
    [
        {
            "id": 24,
            "request_id": "rqst5c130cae6f7609.41056231",
            "business_name": "Code Viable",
            "business_email": "code@viable.com",
            "title": "Load",
        }
    ]
]

这个 JSON 结构在数组内部有一个数组，内部数组的对象就是我要解析的对象。这是我的映射器:

struct JobResponseDataObject: Mappable {

    init?(map: Map) {

    }

    var id: Int?
    var requestId: String?
    var businessName: String?
    var businessEmail: String?

    mutating func mapping(map: Map) {

        id              <- map["id"]
        requestId       <- map["request_id"]
        businessName    <- map["business_name"]
        businessEmail   <- map["business_email"]

    }
}

我已经尝试创建另一个映射器 struct 来保存对象数组 [JobResponseDataObject] 并使用 Alamofire 的 responseArray，但它没有用。我也试过用 0. 作为我的 json id 的前缀，但这也没有用。请帮忙

感谢

Answer 1

事情是这样的……Codable 是 Apple 的一个非常酷的协议(protocol)，用于处理来自 API 的 JSON 响应解析。你得到的是一个数组数组，所以你的东西看起来像这样:

[[ResponseObject]]

所以不管怎样，你会为你的对象创建一个结构，就像这样:

struct ResponseObject: Codable {
    let id: Int?
    let requestId: String?
    let businessName: String?
    let businessEmail: String?
    let title: String?
}

您会注意到我稍微更改了 key 名称(而不是 request_id，我使用了 requestId)。原因是 JSONDecoder 有一个名为 keyDecodingStrategy 的属性，它提供了一系列可供选择的固定解码策略。你会做 convertFromSnakeCase。

您可以将以下代码转储到 Playground 中进行修补。基本上，声明您的结构，将其与 JSON 中的任何键匹配，声明解码器，为其提供解码策略，然后对其进行解码。

以下是您如何进行 Alamofire 调用:

    private let backgroundThread = DispatchQueue(label: "background",
                                                 qos: .userInitiated,
                                                 attributes: .concurrent,
                                                 autoreleaseFrequency: .inherit,
                                                 target: nil)


    Alamofire.request(url).responseJSON(queue: backgroundThread) { (response) in
        guard response.result.error == nil else {
            print("💥KABOOM!💥")
            return
        }

        if let data = response.data {
            let decoder = JSONDecoder()
            decoder.keyDecodingStrategy = .convertFromSnakeCase

            do {
                let parsedResponse = try decoder.decode([[ResponseObject]].self, from: data)
                print(parsedResponse)
            } catch {
                print(error.localizedDescription)
            }
        }
    }

这是您可以在 Playground 上使用的代码。

import UIKit

let json = """
[
    [
        {
        "id": 22,
        "request_id": "rqst5c12fc9e856ae1.06631647",
        "business_name": "Code Viable",
        "business_email": "code@viable.com",
        "title": "Apache Load/Ubuntu",
        }
    ],
    [
        {
        "id": 24,
        "request_id": "rqst5c130cae6f7609.41056231",
        "business_name": "Code Viable",
        "business_email": "code@viable.com",
        "title": "Load",
        }
    ]
]
"""

struct ResponseObject: Codable {
    let id: Int?
    let requestId: String?
    let businessName: String?
    let businessEmail: String?
    let title: String?
}

if let data = json.data(using: .utf8) {
    let decoder = JSONDecoder()
    decoder.keyDecodingStrategy = .convertFromSnakeCase

    do {
        let parsedResponse = try decoder.decode([[ResponseObject]].self, from: data)
        print(parsedResponse)
    } catch {
        print(error.localizedDescription)
    }
}