Swift4.0 Codable使用

摘自:

Swifter - Swift必备tips

Everything about Codable in Swift 4

//
//  main.swift
//  TestCodable
//
//  Created by Adrift on 2017/11/13.
//  Copyright © 2017年 Adrift. All rights reserved.
//

import Foundation


struct Obj: Codable {
    
    struct MenuItem: Codable {
        let value: String
        let onClick: String
        
        enum CodingKeys: String, CodingKey {
            case value
            case onClick = "onclick"
        }
    }
    
    struct Popup: Codable {
        let menuItem: [MenuItem]
        
        enum CodingKeys: String, CodingKey {
            case menuItem = "menuitem"
        }
    }
    
    struct Menu: Codable {
        let id: String
//        let id: String = "hello.id" 通过设置默认值的方式,可以忽略属性赋值
        let value: String
        let popup: Popup
    }
    
    let menu: Menu
}

let str = """
    {
        "menu": {
            "id": "file",
            "value": "File",
            "popup": {
                "menuitem": [
                    {"value": "New", "onclick": "CreateNewDoc()"},
                    {"value": "Open", "onclick": "OpenDoc()"},
                    {"value": "Close", "onclick": "CloseDoc()"}
                ]
            }
        }
    }
"""

if let data = str.data(using: String.Encoding.utf8) {
    do {
        let obj = try JSONDecoder().decode(Obj.self, from: data)
        print(obj.menu.id)
    } catch {
        print(error)
    }
}

//{
//    "size":{
//        "width":150,
//        "height":150
//    },
//    "title":"Apple"
//}
//转成
//{
//    "title":"Apple",
//    "width":150,
//    "height":150
//}

struct Size: Codable {
    var width: Double
    var height: Double
}

struct Photo {
    var title: String
    var size: Size
    
    enum CodingKeys: String, CodingKey {
        case title = "name"
        case width
        case height
    }
}

extension Photo: Encodable {
    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(title, forKey: .title)
        try container.encode(size.width, forKey: .width)
        try container.encode(size.height, forKey: .height)
    }
}

extension Photo: Decodable {
    init(from decoder: Decoder) throws {
        let values = try decoder.container(keyedBy: CodingKeys.self)
        title = try values.decode(String.self, forKey: .title)
        let width = try values.decode(Double.self, forKey: .width)
        let height = try values.decode(Double.self, forKey: .height)
        size = Size(width: width, height: height)
    }
}

--EOF--