从json解析三个对象的数组
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【中文标题】从json解析三个对象的数组【英文标题】：parsing array of three objects from json 【发布时间】：2018-05-02 06:21:39 【问题描述】：我有 3 个对象（国籍、服务和包），我从 JSON 响应中获取它们作为这些对象的 3 个数组。我想从 JSON 响应中解析它们...
类是：
struct Root2 : Decodable
let nationalities : [Nationalities]
let services : [Services]
let packages : [Packages]
struct Packages : Decodable
let id: Int
let name: String
let idService: Int
let nationality: String
let totalPrice: Int
let visitsPerWeek: Int
let excludedDays: String
let excludedShifts: String
let excludedDates: String
let extraVisits: Int
let dateEnabled: String
let dateDisabled: String
let allowedFrom: String
let allowedTo: String
let visitType: String
let createdAt: String?
let updatedAt: String?
struct Nationalities : Decodable
let id: Int
let name: String
let createdAt: String?
let updatedAt: String?
struct Services : Decodable
let id: Int
let name, description: String
let createdAt: String?
let updatedAt: String?
我每个人都有另一个类，例如：
class Service : NSObject, NSCoding
var id: Int
var name, desc: String
var createdAt: String?
var updatedAt: String?
init(id: Int, name: String, desc: String)
self.id = id
self.name = name
self.desc = desc
required convenience init(coder aDecoder: NSCoder)
let id = aDecoder.decodeInteger(forKey: "id")
let name = aDecoder.decodeObject(forKey: "name") as! String
let desc = aDecoder.decodeObject(forKey: "desc") as! String
self.init(id: id, name: name, desc: desc)
func encode(with aCoder: NSCoder)
aCoder.encode(id, forKey: "id")
aCoder.encode(name, forKey: "name")
aCoder.encode(desc, forKey: "desc")
我是这样使用它的：
func GetServicesPackagesNationalities()
let link: String = "my link"
guard let url = URL(string: link) else
print("Error: cannot create URL")
return
let urlRequest = URLRequest(url: url)
let config = URLSessionConfiguration.default
let session = URLSession(configuration: config)
let task = session.dataTask(with: urlRequest)
(data, response, error) in
guard error == nil else
print("error calling GET on /public/api/services")
print(error!)
return
guard let responseData = data else
print("Error: did not receive data")
return
do
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
let result = try decoder .decode(Root2.self, from: responseData)
var nationalities = [Nationality]()
for nationality in result.nationalities
let newnationality = Nationality(id: nationality.id, name: nationality.name)
nationalities.append(newnationality)
print(newnationality.name)
var services = [Service]()
for service in result.services
let newservice = Service(id: service.id, name: service.name, desc: service.description)
services.append(newservice)
print(newservice.name)
var packages = [Package]()
for package in result.packages
let newpackage = Package(id: package.id, name: package.name, idService: package.idService, nationality: package.nationality, totalPrice: package.totalPrice, visitsPerWeek: package.visitsPerWeek, excludedDays: package.excludedDays, excludedShifts: package.excludedShifts, excludedDates: package.excludedDates, extraVisits: package.extraVisits ,dateEnabled: package.dateEnabled , dateDisabled: package.dateDisabled, allowedFrom: package.allowedFrom, allowedTo: package.allowedTo ,visitType: package.visitType)
packages.append(newpackage)
print(newpackage.name)
catch
print("error trying to convert data to JSON")
return
task.resume()
我永远都会得到这个：
尝试将数据转换为 JSON 时出错
我的 json 是：
"nationalities": [
"id": 1,
"name": "Saudi Arabia",
"created_at": "2018-04-24 05:50:41",
"updated_at": "2018-04-24 06:35:29",
"deleted_at": null
,
"id": 2,
"name": "Bahrain",
"created_at": "2018-04-24 05:52:52",
"updated_at": "2018-04-24 05:52:52",
"deleted_at": null
,
],
"services": [
"id": 1,
"name": "Nad",
"description": "Nad ",
"created_at": null,
"updated_at": null,
"deleted_at": null
,
"id": 2,
"name": "Reay",
"description": "Re ",
"created_at": null,
"updated_at": null,
"deleted_at": null
,
],
"packages": [
"id": 1,
"name": "Gold Package",
"id_service": 1,
"nationality": "4",
"total_price": 1000,
"visits_per_week": 2,
"excluded_weekdays": "null",
"excluded_shifts": "null",
"excluded_dates": "1111-11-11",
"extra_visits": 1,
"date_enabled_from": "2018-04-01",
"date_enabled_to": "2018-04-30",
"date_allowed_from": "2018-04-05",
"date_allowed_to": "2018-04-30",
"visit_type": "Multi",
"created_at": "2018-04-26 11:18:45",
"updated_at": "2018-04-26 11:18:45",
"deleted_at": null
]
我不知道我做错了什么..因为我对两个对象进行了相同的尝试并且工作正常..
谁能告诉我我做错了什么？
在用户默认值中使用它们：
存储：
let userDefaults = UserDefaults.standard
let encodedData: Data = NSKeyedArchiver.archivedData(withRootObject: services)
userDefaults.set(encodedData, forKey: "services")
userDefaults.synchronize()
检索：
let decoded = userDefaults.object(forKey: "services") as! Data
let decodedService = NSKeyedUnarchiver.unarchiveObject(with: decoded) as! [Service]
for service in decodedService
print(service.name)
【问题讨论】：
【参考方案1】：请永远不要在 catch 子句中打印无意义的文字字符串，始终打印实际的错误，它会告诉您究竟出了什么问题
catch
print(error)
Package 有很多问题，这里是错误消息（以及修复它们的建议）：
JSON 中没有键"没有与键 CodingKeys 关联的值(stringValue: \"excludedDays\"，转换为excluded_days。"
excluded_days。 删除该属性或将其声明为可选 (String?)
实际的snake_case转换属性应该是"没有与键 CodingKeys 关联的值(stringValue: \"dateEnabled\" 转换为 date_enabled。"
dateEnabledFrom
JSON 中没有键"没有与键 CodingKeys 关联的值(stringValue: \"dateDisabled\" 转换为 date_disabled。"
date_disabled。 删除该属性或将其声明为可选 (String?)
实际的snake_case 转换属性应该是"没有与键 CodingKeys 关联的值(stringValue: \"allowedFrom\", intValue: nil) (\"allowedFrom\")，转换为allowed_from。"
dateAllowedFrom
实际的snake_case转换属性应该是"没有与键 CodingKeys 关联的值(stringValue:\"allowedTo\", intValue: nil) (\"allowedTo\")，转换为allowed_to。"
dateAllowedTo
注意：
你为什么要为Nationality, Service, Package 使用另一个额外的类？它们似乎是多余的。如果您确实需要引用语义，请将 JSON 解码为类。
【讨论】：
谢谢你的工作.. 我会记住始终使用 print(error) 请注意您的笔记.. 我这样做是为了将它们存储在 userdefaults 中.. 如果您可以查看我更新后的帖子的最后一部分.. 有更好的方法吗？ JSON 符合属性列表。您可以将结构编码（到 JSON 甚至属性列表）并直接保存Data 表示。【参考方案2】：
查看Nationality 和Nationalities 之间的区别
您应该使用Nationalities 来解析您的 JSON 响应。
你应该这样做，因为你已经在 Root2 中声明了 Nationalities 对象
var nationalities = [Nationalities]()
for nationality in result.nationalities
let newnationality = Nationalities(id: nationality.id, name: nationality.name)
nationalities.append(newnationality)
print(newnationality.name)
Services 和 Packages 相同，请查找。
【讨论】：
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