背景：項目原本是使用HandyJson來做的數(shù)據(jù)-模型的相互轉(zhuǎn)換怜姿，后面測試發(fā)現(xiàn)在iOS12.1系統(tǒng)的，HandyJson庫會必現(xiàn)崩潰libswiftCoreGraphics image not found，該庫作者已經(jīng)不再更新且不推薦使用了，具體詳細原及可以看下我之前的文章：http://www.reibang.com/p/167167f54a0d
后面就考慮移除HandyJson改為系統(tǒng)Codable去實現(xiàn)數(shù)據(jù)-模型的相互轉(zhuǎn)換强衡，從Handyjson遷移到Codable的過程中竖幔，我發(fā)現(xiàn)了如下問題
我發(fā)現(xiàn)HandyJson在做轉(zhuǎn)換時，如果json數(shù)據(jù)的某個字段的類型與model類的對應(yīng)的字段類型不匹配時砸脊，HandyJson會嘗試自動幫你進行類型轉(zhuǎn)換具篇，但是在Codable中，類型不匹配會導(dǎo)致錯誤凌埂，換句話說就是必須保證jsonObjct中對應(yīng)的屬性名稱是對應(yīng)的驱显，否則該屬性的自動會轉(zhuǎn)換失敗，如果想要轉(zhuǎn)換瞳抓，必須手動實現(xiàn)codable對應(yīng)的方法埃疫。
對于繼承類型，無法自動轉(zhuǎn)換該類型的父類或子類屬性孩哑，如果想要轉(zhuǎn)換栓霜，必須手動實現(xiàn)codable對應(yīng)的方法。
系統(tǒng)對于實體類屬性,會根據(jù)是可選值或不可選值自動調(diào)用對應(yīng)的方法,如果json這個key為空,但是實體類屬性為不可選值,這也會導(dǎo)致對象轉(zhuǎn)換失敗横蜒。
這幾點差異胳蛮，導(dǎo)致對于每個改動的接口销凑，都需要進行一番調(diào)試，查看轉(zhuǎn)換是否正常仅炊，耗費了很多時間斗幼。
以下為實踐過程中總結(jié)的一些經(jīng)驗：
// 遵循codable協(xié)議,即可自動轉(zhuǎn)化,前提:
// 1.類的父類是NSobject或空
// 2.類的屬性類型與json或者jsonObjct中對應(yīng)的類型是對應(yīng)的,否則對象會轉(zhuǎn)化失敗
// 3.類的屬性名稱與json或者jsonObjct中對應(yīng)的屬性名稱是對應(yīng)的,否則該屬性會轉(zhuǎn)換失敗
// 4.如果包含嵌套類型,則嵌套類型也需要實現(xiàn)codable協(xié)議
// 5.系統(tǒng)對于實體類屬性,會根據(jù)是可選值或不可選值自動調(diào)用對應(yīng)的方法,如果json這個key為空,但是實體類屬性為不可選值,這也會導(dǎo)致對象轉(zhuǎn)換失敗
self.childName = try container.decodeIfPresent(String.self, forKey: .childName)
self.childName = try container.decode(String.self, forKey: .childName)
try cotainer.encodeIfPresent(self.childName, forKey: .childName)
try cotainer.encode(self.childName, forKey: .childName)
// 無法自動轉(zhuǎn)化時
// 1.類如果是子類,需要手動實現(xiàn)enum CodingKeys:/ init(from decoder: Decoder)/ encode(to encoder: Encoder)方法,父類需要遵守codable協(xié)議,但可以自動轉(zhuǎn)化
// 2.類的屬性類型不對應(yīng),需要手動實現(xiàn)enum CodingKeys:/ init(from decoder: Decoder)/ encode(to encoder: Encoder)方法
// 3.類的屬性名稱不對應(yīng),需要手動實現(xiàn)enum CodingKeys,所有屬性都必須寫出來
public class JsonToModelViewController: UIViewController {
/*
let jsonStr = """
{
"token_expires_timestamp":1680680304281,
"uid":"4478366175",
"token_expires_time":86400,
"isSetPwd":"0",
"token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE2ODA2ODAzMDQyODEsInBheWxvYWQiOiJ7XCJpbWlVaWRcIjpcIjQ0NzgzNjYxNzVcIixcImZsYWdcIjoxfSJ9.KOBDBhs_pnDPdp85UOebQ6lfJy_Tf_w-YhXj0KlTyok",
"refresh_token":"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE2ODE4MDM1MDQyODEsInBheWxvYWQiOiJ7XCJpbWlVaWRcIjpcIjQ0NzgzNjYxNzVcIixcImZsYWdcIjoyfSJ9.0AJs5VFJjIOfOG3VjoJ9zx75taRS2xFGbrpEamyWoAk",
"refresh_token_expires_timestamp":1681803504281,
"authCode":"0167247243702923",
"refresh_token_expires_time":1209600,
"currentUtcDate":1680593904281,
}
"""
*/
let jsonStr = """
{
"name": "張三",
"age": 20,
"description": "A handsome boy.",
"childName": "小a"
}
"""
let jsonLabel = UILabel(frame: CGRectZero)
let jsonToModelButton = UIButton(type: .system)
let modelToJsonButton = UIButton(type: .system)
let modelToJsonObjButton = UIButton(type: .system)
public override func viewDidLoad() {
super.viewDidLoad()
initViews()
}
func initViews() {
self.navigationItem.title = "json轉(zhuǎn)模型"
self.view.backgroundColor = .white
jsonLabel.text = jsonStr
jsonLabel.numberOfLines = 0
jsonLabel.adjustsFontSizeToFitWidth = true
self.view.addSubview(jsonLabel)
jsonToModelButton.setTitle("json轉(zhuǎn)model", for: .normal)
jsonToModelButton.backgroundColor = .gray
jsonToModelButton.addTarget(self, action: #selector(jsonToModel), for: .touchUpInside)
self.view.addSubview(jsonToModelButton)
modelToJsonButton.setTitle("model轉(zhuǎn)json", for: .normal)
modelToJsonButton.backgroundColor = .gray
modelToJsonButton.addTarget(self, action: #selector(modelToJson), for: .touchUpInside)
self.view.addSubview(modelToJsonButton)
modelToJsonObjButton.setTitle("model轉(zhuǎn)jsonObj", for: .normal)
modelToJsonObjButton.backgroundColor = .gray
modelToJsonObjButton.addTarget(self, action: #selector(modelToJsonObj), for: .touchUpInside)
self.view.addSubview(modelToJsonObjButton)
}
public override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
jsonLabel.snp.makeConstraints { make in
make.left.equalToSuperview().offset(10)
make.right.equalToSuperview().offset(-10)
make.top.equalToSuperview().offset(64)
make.height.lessThanOrEqualTo(300)
}
jsonToModelButton.snp.makeConstraints { make in
make.left.equalToSuperview().offset(10)
make.right.equalToSuperview().offset(-10)
make.top.equalTo(jsonLabel.snp.bottom).offset(10)
make.height.equalTo(44)
}
modelToJsonButton.snp.makeConstraints { make in
make.left.equalToSuperview().offset(10)
make.right.equalToSuperview().offset(-10)
make.top.equalTo(jsonToModelButton.snp.bottom).offset(10)
make.height.equalTo(44)
}
modelToJsonObjButton.snp.makeConstraints { make in
make.left.equalToSuperview().offset(10)
make.right.equalToSuperview().offset(-10)
make.top.equalTo(modelToJsonButton.snp.bottom).offset(10)
make.height.equalTo(44)
}
}
@objc private func jsonToModel() {
do {
// let model = try JSONDecoder().decode(ILAuthInfo.self, from: jsonStr.data(using: .utf8)!)
// let model = try JSONDecoder().decode(ILTestModel.self, from: jsonStr.data(using: .utf8)!)
let model = try JSONDecoder().decode(ILTestChildModel.self, from: jsonStr.data(using: .utf8)!)
print("轉(zhuǎn)換得到的模型:\(model)")
}catch {
imiLogE("轉(zhuǎn)換失敗:\(error)")
}
let jsonStr = """
{"total":2,"cameraCount":1,"items":[{"name":"cm1"},{"name":"cm2"}]}
"""
do {
let model = try JSONDecoder().decode(ILHomeRoomModel.self, from: jsonStr.data(using: .utf8)!)
print("轉(zhuǎn)換得到的模型:\(model)")
}catch {
imiLogE("轉(zhuǎn)換失敗:\(error)")
}
}
@objc private func modelToJson() {
let m1 = ILTestModel()
m1.name = "張三"
let m2 = ILTestModel()
m2.name = "李四"
do {
let jsonData = try JSONEncoder().encode([m1, m2])
let json = String(data: jsonData, encoding: .utf8)
print("轉(zhuǎn)換得到的json1:\(json ?? "空")")
}catch{
imiLogE("轉(zhuǎn)換失敗:\(error)")
}
let m = ILHomeRoomModel()
m.total = 2
m.cameraCount = 1
let cm1 = ILRoomItem()
cm1.name = "cm1"
let cm2 = ILRoomItem()
cm2.name = "cm2"
m.items = [cm1, cm2]
do {
let jsonData = try JSONEncoder().encode(m)
let json = String(data: jsonData, encoding: .utf8)
print("轉(zhuǎn)換得到的json2:\(json ?? "空")")
}catch{
imiLogE("轉(zhuǎn)換失敗:\(error)")
}
let bm = ILTestBigModel()
bm.bigName = "大名"
bm.child = m2
do {
let jsonData = try JSONEncoder().encode(bm)
let json = String(data: jsonData, encoding: .utf8)
print("轉(zhuǎn)換得到的json3:\(json ?? "空")")
}catch{
imiLogE("轉(zhuǎn)換失敗:\(error)")
}
}
@objc private func modelToJsonObj() {
let model = ILTestModel()
model.name = "李四"
model.smallName = "a"
model.des = "啊哈"
model.age = 22
let jsonObj = ILCodableUtil.modelToJsonObject(model) as? [String: Any]
}
}
@objcMembers
public class ILTestModel: NSObject, Codable {
var name: String?
var smallName: String?
var des: String?
var age: Int = 0
public override var description: String {
"name:\(name ?? "空"), smallName:\(smallName ?? "空"), des:\(des ?? "空"), age:\(age)"
}
// enum CodingKeys: String, CodingKey {
// case name
// case smallName
// case des = "description"
// case age
// }
//手動實現(xiàn)
/*
public required init(from decoder: Decoder) throws {
super.init()
let container = try decoder.container(keyedBy: CodingKeys.self)
self.nickName = try container.decodeIfPresent(String.self, forKey: .nickName)
self.deviceName = try container.decodeIfPresent(String.self, forKey: .deviceName)
self.mac = try container.decodeIfPresent(String.self, forKey: .mac)
self.productKey = try container.decodeIfPresent(String.self, forKey: .productKey)
self.token = try container.decodeIfPresent(String.self, forKey: .token)
self.categoryKey = try container.decodeIfPresent(String.self, forKey: .categoryKey)
//特殊處理一下字典
let dicData = try container.decodeIfPresent(Data.self, forKey: .extraDeviceInfo)
self.extraDeviceInfo = ILLocalDeviceKeychainUtil.dataToDictionary(dicData);
}
public func encode(to encoder: Encoder) throws {
//super.encode(to: encoder)
var cotainer = encoder.container(keyedBy: CodingKeys.self)
try cotainer.encodeIfPresent(self.nickName, forKey: .nickName)
try cotainer.encodeIfPresent(self.deviceName, forKey: .deviceName)
try cotainer.encodeIfPresent(self.mac, forKey: .mac)
try cotainer.encodeIfPresent(self.productKey, forKey: .productKey)
try cotainer.encodeIfPresent(self.token, forKey: .token)
try cotainer.encodeIfPresent(self.categoryKey, forKey: .categoryKey)
//特殊處理一下字典
if let dicData = ILLocalDeviceKeychainUtil.dictionaryToData(self.extraDeviceInfo) {
try cotainer.encodeIfPresent(dicData, forKey: .extraDeviceInfo)
}
}
*/
}
@objcMembers public class ILTestBigModel: NSObject, Codable {
var bigName: String?
var child: ILTestModel?
}
/// 子類想要使用Codable轉(zhuǎn)換,必須手寫以下實現(xiàn)
/// 與現(xiàn)有的 NSCoding API (NSKeyedArchiver) 不同，為了靈活性和安全性抚垄，新的 Swift 4 Codable 實現(xiàn)不會將有關(guān)編碼類型的類型信息寫入生成的檔案中蜕窿。因此，在解碼時呆馁，API 只能使用您提供的具體類型來解碼值（在您的情況下是超類類型）渠羞。
@objcMembers public class ILTestChildModel: ILTestModel {
var childName: String?
enum CodingKeys: String, CodingKey {
case childName = "childName"
}
public required init(from decoder: Decoder) throws {
try super.init(from: decoder)
let container = try decoder.container(keyedBy: CodingKeys.self)
self.childName = try container.decodeIfPresent(String.self, forKey: .childName)
}
public override func encode(to encoder: Encoder) throws {
var cotainer = encoder.container(keyedBy: CodingKeys.self)
try cotainer.encodeIfPresent(self.childName, forKey: .childName)
}
}
