Swift使用编解码库Codable的过程详解

typealias Codable = Decodable & Encodable
public protocol Decodable {
    public init(from decoder: Decoder) throws
}
public protocol Encodable {
    public func encode(to encoder: Encoder) throws
}

struct User: Codable {
    var name: String
    var age: Int
}

let user = JSONDecoder().decode(User.self, from: jsonData)

let jsonData = JSONEncoder().encode(user)

struct User: Codable {
    var name: String?
    var age: Int?
    static func convertFromDict(dict: NSDictionary) -> User? {
        var user: User?
        do {
            let data = try JSONSerialization.data(withJSONObject: dict, options: [])
            let decoder = JSONDecoder()
            user = try decoder.decode(User.self, from: data)
        } catch {
            print(error)
        }
        return user
    }
    func convertToDict() -> NSDictionary? {
        var dict: NSDictionary?
        do {
            let encoder = JSONEncoder()
            let data = try encoder.encode(self)
            dict = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as? NSDictionary
        } catch {
            print(error)
        }
        return dict
    }
}