仅使用 Swift 4 Codable 解码 JSON 数据中的数组

Question

我正在使用 Swift 4 Codable 并且我正在从我的网络服务中收到此 JSON：

{
    "status": "success",
    "data": {
        "time": "00:02:00",
        "employees": [
            {
                "id": 001,
                "name": "foo"
            }, 
            {
                "id": 002,
                "name": "bar"
            }
        ]
    }
}

我只想将employees数组解码为employee对象（时间属性只会保存一次），但没有任何效果。
我阅读了很多关于 Swift 4 Codable 的资料，但不知道如何解码这个数组。

编辑：我的员工class：

import Foundation

struct Employee: Codable {
    var id: Int
    var time: Date

    enum CodingKeys: String, CodingKey {
        case id = "id"
        case time = "time"
    }
}

请求：

  Alamofire.SessionManager.default.request(Router.syncUsers)
            .validate(contentType: ["application/json"])
            .responseJSON { response in
                if response.response?.statusCode == 200 {
        guard let jsonDict = response as? Dictionary<String, Any>,
                    let feedPage = Employee(from: jsonDict as! Decoder) else {
                    return
                }

                guard let response = response.result.value as? [String: Any] else {
                    return
                }

                guard let data = response["data"] as? [String: Any] else {
                    return
                }

                guard let users = data["employees"] else {
                    return
                }

                guard let usersData = try? JSONSerialization.data(withJSONObject: users, options: .prettyPrinted) else {
                    return
                }

                guard let decoded = try? JSONSerialization.jsonObject(with: usersData, options: []) else {
                    return
                }

                let decoder = JSONDecoder()

                guard let employee = try? decoder.decode(Employee.self, from: usersData) else {
                    print("errorMessage")
                    return
                }
                } else {
                    print("errorMessage")
                }
        }

Answer 1

使用 Codable 时，如果不解码外部数据，则无法解码内部数据。

但这很简单，例如您可以省略所有 CodingKeys。

struct Root : Decodable {
    let status : String
    let data : EmployeeData
}

struct EmployeeData : Decodable {
    let time : String
    let employees : [Employee]
}

struct Employee: Decodable {
    let id: Int
    let name: String
}

let jsonString = """
{
    "status": "success",
    "data": {
        "time": "00:02:00",
        "employees": [
            {"id": 1, "name": "foo"},
            {"id": 2, "name": "bar"}
        ]
    }
}
"""


do {
    let data = Data(jsonString.utf8)
    let result = try JSONDecoder().decode(Root.self, from: data)
    for employee in result.data.employees {
        print(employee.name, employee.id)
    }
} catch { print(error) }

Answer 2

您可以使用 quicktype 轻松解决此类 JSON 解析问题。只需在左侧粘贴您的 JSON，您就会在右侧获得类型和 serialization/deserialization 代码，适用于各种语言。以下是它为您的 JSON:

生成的类型

struct Employees: Codable {
    let status: String
    let data: EmployeesData
}

struct EmployeesData: Codable {
    let time: String
    let employees: [Employee]
}

struct Employee: Codable {
    let id: Int
    let name: String
}

仅使用 Swift 4 Codable 解码 JSON 数据中的数组

Decode an array inside JSON data only using Swift 4 Codable

swift

swift4

codable