在带有继承的Swift 4中使用Decodable

Question

使用类继承是否会破坏类的可解码性。例如下面的代码class Server : Codable {    var id : Int?}class Development : Server {    var name : String?    var userId : Int?}var json = "{\"id\" : 1,\"name\" : \"Large Building Development\"}"let jsonDecoder = JSONDecoder()let item = try jsonDecoder.decode(Development.self, from:json.data(using: .utf8)!) as Developmentprint(item.id ?? "id is nil")print(item.name ?? "name is nil") here输出为：1name is nil现在，如果我将其反转，则名称会解码，而id不会。class Server {    var id : Int?}class Development : Server, Codable {    var name : String?    var userId : Int?}var json = "{\"id\" : 1,\"name\" : \"Large Building Development\"}"let jsonDecoder = JSONDecoder()let item = try jsonDecoder.decode(Development.self, from:json.data(using: .utf8)!) as Developmentprint(item.id ?? "id is nil")print(item.name ?? "name is nil")输出为：id is nilLarge Building Development而且您不能在两个类中都表示Codable。

Answer 1

override func encode(to encoder: Encoder) throws {

    try super.encode(to: encoder)

    var container = encoder.container(keyedBy: CodingKeys.self)

    try container.encode(employeeID, forKey: .employeeID)

}

对于解码，我这样做：

 required init(from decoder: Decoder) throws {

    try super.init(from: decoder)

    let values = try decoder.container(keyedBy: CodingKeys.self)

    total = try values.decode(Int.self, forKey: .total)

  }

private enum CodingKeys: String, CodingKey

{

    case total

}