在Swift中将复杂的JSON保存到核心数据 [英] Save complex JSON to Core Data in Swift

问题描述

我想将Web服务的JSON结果保存到Core数据，以下是JSON解析的代码。

I want to save the JSON Result from web service to Core data, following is the code for JSON parsing.

if let jsonResult = try JSONSerialization.jsonObject(with: JSONData!, options: [.mutableContainers]) as? [String: AnyObject]

如果我打印jsonResult，则输出为

If i prints jsonResult, following is the output

["Code": 00, "Desc": success, "iinData": <__NSArrayM 0x1c02531a0>
{
  name = "AAA";
  iin = 123456;
  isOn = 0;
},
{
  name = "Allahabad Bank";
  iin = 608112;
  isOn = 0;
},
)

我可以插入代码， Desc 进入Entity1，但如何将innData插入Entity2。

I can able to insert Code, Desc into Entity1, but how to insert innData into Entity2 .

Entity1结构 < a href = https://i.stack.imgur.com/FUW1b.png rel = nofollow noreferrer> Entity2结构

以下是将JSON结果插入核心数据的代码

Following is the code for inserting JSON result into core data

func createEntity1From(dictionary: [String: AnyObject]) -> NSManagedObject? {
    let context = CoreDataStack.sharedInstance.persistentContainer.viewContext
    if let Entity1 = NSEntityDescription.insertNewObject(forEntityName: "ParamDownload", into: context) as? ParamDownload {
        Entity1.Code= dictionary["name"] as? String
        Entity1.desc = dictionary["desc"] as? String
        return Entity1
    }
}

推荐答案

使用 Decodable

$ b $将JSON直接解码为Core Data很容易b

• 首先创建 CodingUserInfoKey 和 JSONDecoder 的扩展名，以便能够传递托管对象context

• First of all create extensions of CodingUserInfoKey and JSONDecoder to be able to pass the managed object context

extension CodingUserInfoKey {
    static let context = CodingUserInfoKey(rawValue: "context")!
}

extension JSONDecoder {
    convenience init(context: NSManagedObjectContext) {
        self.init()
        self.userInfo[.context] = context
    }
}

为 Decodable

class Name: NSManagedObject, Decodable {

class ParamDownload: NSManagedObject, Decodable {

在类中（不是扩展名）添加

private enum CodingKeys: String, CodingKey { case name, iin, isOn }

required convenience init(from decoder: Decoder) throws {
    guard let context = decoder.userInfo[.context] as? NSManagedObjectContext else { fatalError("NSManagedObjectContext is missing") }
    let entity = NSEntityDescription.entity(forEntityName: "Name", in: context)!
    self.init(entity: entity, insertInto: context)
    let values = try decoder.container(keyedBy: CodingKeys.self)
    name = try values.decode(String.self, forKey: .name)
    iin = try values.decode(String.self.self, forKey: .iin)
    isOn = try values.decode(Bool.self.self, forKey: .isOn)
}

在类 ParamDownload （不是扩展名）

private enum CodingKeys: String, CodingKey { case code = "Code", desc = "Desc", names = "iinData" }

required convenience init(from decoder: Decoder) throws {
    guard let context = decoder.userInfo[.context] as? NSManagedObjectContext else { fatalError("NSManagedObjectContext is missing") }
    let entity = NSEntityDescription.entity(forEntityName: "ParamDownload", in: context)!
    self.init(entity: entity, insertInto: context)
    let values = try decoder.container(keyedBy: CodingKeys.self)
    code = try values.decode(String.self, forKey: .code)
    desc = try values.decode(String.self, forKey: .desc)
    names = try values.decode(Set<Name>.self, forKey: .names)
    names.forEach { $0.pd = self }
}

要解码JSON，请使用便捷的初始化程序创建解码器

To decode the JSON create the Decoder with the convenience initializer

let decoder = JSONDecoder(context: CoreDataStack.sharedInstance.persistentContainer.viewContext)

init 处理关系的方法。

我建议声明Core Data属性，尽可能非-可选。

如果某个属性必须保留为可选属性，则将 decode 替换为 decodeIfPresent 。

I recommend to declare the Core Data attributes as much non-optional as possible.
If an attribute must be remain optional replace decode with decodeIfPresent.

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