堆棧內存溢出
  簡體   English   中英

使用 iOS Swift 中的可編碼解析嵌套的 json 響應數據？

[英]Parsing nested json response data using codable in iOS Swift?

 原文  2019-11-18 05:56:24  5   2    json/ swift/ xcode/ nested/ codable

問題描述

我正在嘗試在 swift 4 中解析 json 數據。它打印 nil 值。 我找不到這是什么問題？

這是 model class：

public struct TaskID: Decodable {

let embedded: Embedded?
let count: Int?

enum CodingKeys: String, CodingKey {
    case count = "count"
    case embedded = "_embedded"
  }
}

 public struct Embedded: Decodable {


let task: [Task]?
enum CodingKeys: String, CodingKey {
       case task = "task"
   }

 }

public struct Task : Decodable {

let id : String?
let name: String?
let assignee: String?
let created: String?
let processDefinitionId: String?
enum CodingKeys: String, CodingKey {
    case id = "id"
    case name = "name"
    case assignee = "assignee"
    case created = "created"
    case processDefinitionId = "processDefinitionId"


 }

}

這是 json：

{
"_links": {
    "self": {
        "href": "/task"
    }
},
"_embedded": {

    "task": [
        {
            "_links": {
                "assignee": {
                    "href": "/user/demo"
                },
                "execution": {
                    "href": "/execution/1b64cf75-0616-11ea-8860-120ef5ab2c25"
                },
                "identityLink": {
                    "href": "/task/1b64f688-0616-11ea-8860-120ef5ab2c25/identity-links"
                },
                "processDefinition": {
                    "href": "/process-definition/quickEvaluation:1:129ce2b1-0616-11ea-8860-120ef5ab2c25"
                },
                "processInstance": {
                    "href": "/process-instance/1b64cf75-0616-11ea-8860-120ef5ab2c25"
                },
                "self": {
                    "href": "/task/1b64f688-0616-11ea-8860-120ef5ab2c25"
                }
            },
            "_embedded": {
                "variable": []
            },
            "id": "1b64f688-0616-11ea-8860-120ef5ab2c25",
            "name": "Quick Evaluation",
            "assignee": "demo",
            "created": "2019-11-13T13:04:20.687+0000",
            "due": null,
            "followUp": null,
            "delegationState": null,
            "description": null,
            "executionId": "1b64cf75-0616-11ea-8860-120ef5ab2c25",
            "owner": null,
            "parentTaskId": null,
            "priority": 50,
            "processDefinitionId": "quickEvaluation:1:129ce2b1-0616-11ea-8860-120ef5ab2c25",
            "processInstanceId": "1b64cf75-0616-11ea-8860-120ef5ab2c25",
            "taskDefinitionKey": "QuickEvaluation",
            "caseExecutionId": null,
            "caseInstanceId": null,
            "caseDefinitionId": null,
            "suspended": false,
            "formKey": "a8apps:suryoday:gng:v0.1.0:kycUpload",
            "tenantId": null
        },
        {
            "_links": {
                "assignee": {
                    "href": "/user/demo"
                },
                "execution": {
                    "href": "/execution/412a03b7-06ae-11ea-8860-120ef5ab2c25"
                },
                "identityLink": {
                    "href": "/task/412a2aca-06ae-11ea-8860-120ef5ab2c25/identity-links"
                },
                "processDefinition": {
                    "href": "/process-definition/quickEvaluation:1:129ce2b1-0616-11ea-8860-120ef5ab2c25"
                },
                "processInstance": {
                    "href": "/process-instance/412a03b7-06ae-11ea-8860-120ef5ab2c25"
                },
                "self": {
                    "href": "/task/412a2aca-06ae-11ea-8860-120ef5ab2c25"
                }
            },
            "_embedded": {
                "variable": [
                    {
                        "_links": {
                            "self": {
                                "href": "/process-instance/412a03b7-06ae-11ea-8860-120ef5ab2c25/variables/loanAmount"
                            }
                        },
                        "_embedded": null,
                        "name": "loanAmount",
                        "value": "650000",
                        "type": "String",
                        "valueInfo": {}
                    },
                    {
                        "_links": {
                            "self": {
                                "href": "/process-instance/412a03b7-06ae-11ea-8860-120ef5ab2c25/variables/firstName"
                            }
                        },
                        "_embedded": null,
                        "name": "firstName",
                        "value": "Kamesh",
                        "type": "String",
                        "valueInfo": {}
                    }
                ]
            },
            "id": "412a2aca-06ae-11ea-8860-120ef5ab2c25",
            "name": "Quick Evaluation",
            "assignee": "demo",
            "created": "2019-11-14T07:13:27.558+0000",
            "due": null,
            "followUp": null,
            "delegationState": null,
            "description": null,
            "executionId": "412a03b7-06ae-11ea-8860-120ef5ab2c25",
            "owner": null,
            "parentTaskId": null,
            "priority": 50,
            "processDefinitionId": "quickEvaluation:1:129ce2b1-0616-11ea-8860-120ef5ab2c25",
            "processInstanceId": "412a03b7-06ae-11ea-8860-120ef5ab2c25",
            "taskDefinitionKey": "QuickEvaluation",
            "caseExecutionId": null,
            "caseInstanceId": null,
            "caseDefinitionId": null,
            "suspended": false,
            "formKey": "a8apps:suryoday:gng:v0.1.0:kycUpload",
            "tenantId": null
        }

    ]
},
"count": 13
}

這是url請求：

 // MARK: - URLRequestConvertible
func asURLRequest() throws -> URLRequest {
    let url = try K.ProductionServer.baseURL.asURL()

    var urlRequest = URLRequest(url: url.appendingPathComponent(path))
    print(urlRequest)
    // HTTP Method
    urlRequest.httpMethod = method.rawValue

    let authToken = UserDefaults.standard.string(forKey: "authToken")
    let bearerToken: String = "Bearer " + (authToken ?? "")
    print("baearer token::\(bearerToken)")

    // Common Headers
    urlRequest.setValue(ContentType.json.rawValue, forHTTPHeaderField: HTTPHeaderField.acceptType.rawValue)
    urlRequest.setValue(ContentType.json.rawValue, forHTTPHeaderField: HTTPHeaderField.contentType.rawValue)
    urlRequest.setValue(bearerToken, forHTTPHeaderField: HTTPHeaderField.authentication.rawValue)

    // Parameters
    if let parameters = parameters {
        do {
            urlRequest.httpBody = try JSONSerialization.data(withJSONObject: parameters, options: [])
        } catch {
            throw AFError.parameterEncodingFailed(reason: .jsonEncodingFailed(error: error))
        }
    }

    return urlRequest
}

這是alamofire請求：

 import Foundation
import Alamofire

public class APIClient {
@discardableResult
private static func performRequest<T:Decodable>(route:APIRouter, decoder: JSONDecoder = JSONDecoder(), completion:@escaping (AFResult<T>)->Void) -> DataRequest {

    return AF.request(route)
                    .responseDecodable (decoder: decoder){ (response: AFDataResponse<T>) in
                        completion(response.result)
                        print("framework response::",response.result)
    }
}

public static func taskID(id: String, completion:@escaping (AFResult< [TaskID]>)->Void) {

    performRequest(route: APIRouter.TaskById(id: id), completion: completion)
}


}//APIClient

最初它顯示Dictionary, Swift.DecodingError.Context(codingPath: [], debugDescription: "Expeded to decode Dictionary 但找到了一個數組。但現在我在控制台日志中得到 nil。不知道為什么我得到 nil 值. 根據我的 json 響應，結構是否正確？我正在努力獲取嵌套數據。

非常感謝任何幫助。

2 個解決方案

解決方案1
 1 已采納  2019-11-18 06:22:18

你的結構是正確的。 請參閱下面的操場以獲取證據； 我沒有收到錯誤。 當您沒有完整的數據集並且您假設響應中的某些可選字段是非可選字段時， nil是非常常見的結果，因為您在示例數據中看到了它（您的示例不一定具有代表性）。 如果沒有來自服務器的實際規范，您需要確定哪些字段無法解碼，並且您可能需要獲取一堆數據來確定哪些字段是真正可選的。 您可以通過在上面的 AF 項目中添加錯誤處理代碼或將您的響應粘貼到下面的操場中來做到這一點。 無論哪種方式，解碼錯誤都應該告訴您哪個字段不存在。

import PlaygroundSupport
import UIKit
import WebKit


public struct TaskID: Decodable {

let embedded: Embedded?
let count: Int?

enum CodingKeys: String, CodingKey {
    case count = "count"
    case embedded = "_embedded"
  }
}

 public struct Embedded: Decodable {


let task: [Task]?
enum CodingKeys: String, CodingKey {
       case task = "task"
   }

 }

public struct Task : Decodable {

let id : String?
let name: String?
let assignee: String?
let created: String?
let processDefinitionId: String?
enum CodingKeys: String, CodingKey {
    case id = "id"
    case name = "name"
    case assignee = "assignee"
    case created = "created"
    case processDefinitionId = "processDefinitionId"


 }

}


let data = """
{
"_links": {
    "self": {
        "href": "/task"
    }
},
"_embedded": {

    "task": [
        {
            "_links": {
                "assignee": {
                    "href": "/user/demo"
                },
                "execution": {
                    "href": "/execution/1b64cf75-0616-11ea-8860-120ef5ab2c25"
                },
                "identityLink": {
                    "href": "/task/1b64f688-0616-11ea-8860-120ef5ab2c25/identity-links"
                },
                "processDefinition": {
                    "href": "/process-definition/quickEvaluation:1:129ce2b1-0616-11ea-8860-120ef5ab2c25"
                },
                "processInstance": {
                    "href": "/process-instance/1b64cf75-0616-11ea-8860-120ef5ab2c25"
                },
                "self": {
                    "href": "/task/1b64f688-0616-11ea-8860-120ef5ab2c25"
                }
            },
            "_embedded": {
                "variable": []
            },
            "id": "1b64f688-0616-11ea-8860-120ef5ab2c25",
            "name": "Quick Evaluation",
            "assignee": "demo",
            "created": "2019-11-13T13:04:20.687+0000",
            "due": null,
            "followUp": null,
            "delegationState": null,
            "description": null,
            "executionId": "1b64cf75-0616-11ea-8860-120ef5ab2c25",
            "owner": null,
            "parentTaskId": null,
            "priority": 50,
            "processDefinitionId": "quickEvaluation:1:129ce2b1-0616-11ea-8860-120ef5ab2c25",
            "processInstanceId": "1b64cf75-0616-11ea-8860-120ef5ab2c25",
            "taskDefinitionKey": "QuickEvaluation",
            "caseExecutionId": null,
            "caseInstanceId": null,
            "caseDefinitionId": null,
            "suspended": false,
            "formKey": "a8apps:suryoday:gng:v0.1.0:kycUpload",
            "tenantId": null
        },
        {
            "_links": {
                "assignee": {
                    "href": "/user/demo"
                },
                "execution": {
                    "href": "/execution/412a03b7-06ae-11ea-8860-120ef5ab2c25"
                },
                "identityLink": {
                    "href": "/task/412a2aca-06ae-11ea-8860-120ef5ab2c25/identity-links"
                },
                "processDefinition": {
                    "href": "/process-definition/quickEvaluation:1:129ce2b1-0616-11ea-8860-120ef5ab2c25"
                },
                "processInstance": {
                    "href": "/process-instance/412a03b7-06ae-11ea-8860-120ef5ab2c25"
                },
                "self": {
                    "href": "/task/412a2aca-06ae-11ea-8860-120ef5ab2c25"
                }
            },
            "_embedded": {
                "variable": [
                    {
                        "_links": {
                            "self": {
                                "href": "/process-instance/412a03b7-06ae-11ea-8860-120ef5ab2c25/variables/loanAmount"
                            }
                        },
                        "_embedded": null,
                        "name": "loanAmount",
                        "value": "650000",
                        "type": "String",
                        "valueInfo": {}
                    },
                    {
                        "_links": {
                            "self": {
                                "href": "/process-instance/412a03b7-06ae-11ea-8860-120ef5ab2c25/variables/firstName"
                            }
                        },
                        "_embedded": null,
                        "name": "firstName",
                        "value": "Kamesh",
                        "type": "String",
                        "valueInfo": {}
                    }
                ]
            },
            "id": "412a2aca-06ae-11ea-8860-120ef5ab2c25",
            "name": "Quick Evaluation",
            "assignee": "demo",
            "created": "2019-11-14T07:13:27.558+0000",
            "due": null,
            "followUp": null,
            "delegationState": null,
            "description": null,
            "executionId": "412a03b7-06ae-11ea-8860-120ef5ab2c25",
            "owner": null,
            "parentTaskId": null,
            "priority": 50,
            "processDefinitionId": "quickEvaluation:1:129ce2b1-0616-11ea-8860-120ef5ab2c25",
            "processInstanceId": "412a03b7-06ae-11ea-8860-120ef5ab2c25",
            "taskDefinitionKey": "QuickEvaluation",
            "caseExecutionId": null,
            "caseInstanceId": null,
            "caseDefinitionId": null,
            "suspended": false,
            "formKey": "a8apps:suryoday:gng:v0.1.0:kycUpload",
            "tenantId": null
        }

    ]
},
"count": 13
}
""".data(using: .utf8)!

let decoder = JSONDecoder()
do {
  let decoded = try decoder.decode(TaskID.self, from: data)
  print(decoded)
} catch ( let error ) {
  print(error.localizedDescription)
}

解決方案2
 0  2019-11-18 06:28:49

import Foundation

// MARK: - Task
struct Task: Codable {
let links: VariableLinks?
let embedded: TaskEmbedded?
let count: Int?

enum CodingKeys: String, CodingKey {
    case links = "_links"
    case embedded = "_embedded"
    case count = "count"
}
}

// MARK: - TaskEmbedded
struct TaskEmbedded: Codable {
let task: [TaskElement]?

enum CodingKeys: String, CodingKey {
case task = "task"
}
}

// MARK: - TaskElement
struct TaskElement: Codable {
let links: TaskLinks?
let embedded: TaskEmbeddedClass?
let id: String?
let name: String?
let assignee: String?
let created: String?
let due: String?
let followUp: String?
let delegationState: String?
let taskDescription: String?
let executionId: String?
let owner: String?
let parentTaskId: Int?
let priority: Int?
let processDefinitionId: String?
let processInstanceId: String?
let taskDefinitionKey: String?
let caseExecutionId: Int?
let caseInstanceId: Int?
let caseDefinitionId: Int?
let suspended: Bool?
let formKey: String?
let tenantId: Int?

enum CodingKeys: String, CodingKey {
case links = "_links"
case embedded = "_embedded"
case id = "id"
case name = "name"
case assignee = "assignee"
case created = "created"
case due = "due"
case followUp = "followUp"
case delegationState = "delegationState"
case taskDescription = "description"
case executionId = "executionId"
case owner = "owner"
case parentTaskId = "parentTaskId"
case priority = "priority"
case processDefinitionId = "processDefinitionId"
case processInstanceId = "processInstanceId"
case taskDefinitionKey = "taskDefinitionKey"
case caseExecutionId = "caseExecutionId"
case caseInstanceId = "caseInstanceId"
case caseDefinitionId = "caseDefinitionId"
case suspended = "suspended"
case formKey = "formKey"
case tenantId = "tenantId"
}
}

// MARK: - TaskEmbeddedClass
struct TaskEmbeddedClass: Codable {
let variable: [Variable]?

enum CodingKeys: String, CodingKey {
case variable = "variable"
}
}

// MARK: - Variable
struct Variable: Codable {
let links: VariableLinks?
let embedded: String?
let name: String?
let value: String?
let type: String?
let valueInfo: ValueInfo?

enum CodingKeys: String, CodingKey {
case links = "_links"
case embedded = "_embedded"
case name = "name"
case value = "value"
case type = "type"
case valueInfo = "valueInfo"
}
}

// MARK: - VariableLinks
struct VariableLinks: Codable {
let linksSelf: SelfClass?

enum CodingKeys: String, CodingKey {
case linksSelf = "self"
}
}

// MARK: - SelfClass
struct SelfClass: Codable {
let href: String?

enum CodingKeys: String, CodingKey {
case href = "href"
}
}

// MARK: - ValueInfo
struct ValueInfo: Codable {
}

// MARK: - TaskLinks
struct TaskLinks: Codable {
let assignee: SelfClass?
let execution: SelfClass?
let identityLink: SelfClass?
let processDefinition: SelfClass?
let processInstance: SelfClass?
let linksSelf: SelfClass?

enum CodingKeys: String, CodingKey {
case assignee = "assignee"
case execution = "execution"
case identityLink = "identityLink"
case processDefinition = "processDefinition"
case processInstance = "processInstance"
case linksSelf = "self"
}
}

此外，如果你覺得懶惰，你可以使用quicktype.io ，因為nil是 decodedable 的一個非常常見的響應，你可以擴展 DataRequest 來解析和獲取請求中的值，就像使用responseDecodable一樣，在這里你可以使用類似的東西這個，

 extension DataRequest {
    fileprivate func decodableResponseSerializer<T: Decodable>() -> DataResponseSerializer<T> {
        return DataResponseSerializer { _, response, data, error in
            guard error == nil else { return .failure(error!) }

            guard let data = data else {
                return .failure(AFError.responseSerializationFailed(reason: .inputDataNil))
            }

            return Result { try newJSONDecoder().decode(T.self, from: data) }
        }
    }

    @discardableResult
    fileprivate func responseDecodable<T: Decodable>(queue: DispatchQueue? = nil, completionHandler: @escaping (DataResponse<T>) -> Void) -> Self {
        return response(queue: queue, responseSerializer: decodableResponseSerializer(), completionHandler: completionHandler)
    }
}

然后你可以這樣稱呼它

Alamofire.request(url, method:.post, parameters: parameters, headers: headers)
        .responseDecodable { (response: DataResponse< Task >) in completion(response.result) }

當你得到這樣的東西時，只有當你有不同類型的數據而不是你指定的數據時才會出現。

暫無
暫無

聲明:本站的技術帖子網頁，遵循CC BY-SA 4.0協議，如果您需要轉載，請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.

相關問題 Swift 4 - 使用Codable協議進行JSON解析（嵌套數據） 在Swift中使用Codable解析JSON響應 使用可編碼在Swift 4中解析嵌套JSON 使用Codable解析嵌套的JSON 使用Codable解析JSON響應會在swift中產生錯誤 Codable Swift JSON 解析嵌套 JSON 使用Codable快速解析JSON 4 在Swift中使用可編碼解析JSON Swift IOS 無法使用 Codable 訪問 json 數組數據 Swift Codable Json 響應
相關標簽
 
粵ICP備18138465號  © 2020-2024 STACKOOM.COM