【KakaJSON手册】03_JSON转Model_03_key处理
有时候，服务器返回的JSON数据的key跟客户端模型的属性名可能不一致，比如客户端遵守驼峰规范叫做
nickName，而服务器端返回的JSON可能叫做nick_name。这时候为了保证数据转换成功，就需要对模型属性名和JSON的key进行相应的映射。KakaJSON提供了简单易用的映射方式。
最基本的用法
struct Person: Convertible {
var nickName: String = ""
var mostFavoriteNumber: Int = 0
var birthday: String = ""
// 实现kj_modelKey方法
// 会传入模型的属性`property`作为参数，返回值就是属性对应的key
func kj_modelKey(from property: Property) -> ModelPropertyKey {
// 根据属性名来返回对应的key
switch property.name {
// 模型的`nickName`属性 对应 JSON中的`nick_name`
case "nickName": return "nick_name"
// 模型的`mostFavoriteNumber `属性 对应 JSON中的`most_favorite_number `
case "mostFavoriteNumber": return "most_favorite_number"
// 模型剩下的其他属性，直接用属性名作为JSON的key（属性名和key保持一致）
default: return property.name
}
}
}
let nick_name = "ErHa"
let most_favorite_number = 666
let birthday = "2011-10-12"
let json: [String: Any] = [
"nick_name": nick_name,
"most_favorite_number": most_favorite_number,
"birthday": birthday
]
let student = json.kj.model(Person.self)
XCTAssert(student.nickName == nick_name)
XCTAssert(student.mostFavoriteNumber == most_favorite_number)
XCTAssert(student.birthday == birthday)
驼峰 -> 下划线
struct Person: Convertible {
var nickName: String = ""
var mostFavoriteNumber: Int = 0
var birthday: String = ""
func kj_modelKey(from property: Property) -> ModelPropertyKey {
// 由于开发中可能经常遇到`驼峰`映射`下划线`的需求，KakaJSON已经内置了处理方法
// 直接调用字符串的underlineCased方法就可以从`驼峰`转为`下划线`
// `nickName` -> `nick_name`
return property.name.kj.underlineCased()
}
}
let nick_name = "ErHa"
let most_favorite_number = 666
let birthday = "2011-10-12"
let json: [String: Any] = [
"nick_name": nick_name,
"most_favorite_number": most_favorite_number,
"birthday": birthday
]
let student = json.kj.model(Person.self)
XCTAssert(student.nickName == nick_name)
XCTAssert(student.mostFavoriteNumber == most_favorite_number)
XCTAssert(student.birthday == birthday)
下划线 -> 驼峰
struct Person: Convertible {
var nick_name: String = ""
var most_favorite_number: Int = 0
var birthday: String = ""
// KakaJSON也给字符串内置了camelCased方法，可以由`下划线`转为`驼峰`
func kj_modelKey(from property: Property) -> ModelPropertyKey {
// `nick_name` -> `nickName`
return property.name.kj.camelCased()
}
}
let nickName = "ErHa"
let mostFavoriteNumber = 666
let birthday = "2011-10-12"
let json: [String: Any] = [
"nickName": nickName,
"mostFavoriteNumber": mostFavoriteNumber,
"birthday": birthday
]
let student = json.kj.model(Person.self)
XCTAssert(student.nick_name == nickName)
XCTAssert(student.most_favorite_number == mostFavoriteNumber)
XCTAssert(student.birthday == birthday)
继承
// 子类可以继承父类的实现
class Person: Convertible {
var nickName: String = ""
required init() {}
func kj_modelKey(from property: Property) -> ModelPropertyKey {
// `nickName` -> `nick_ame`
return property.name.kj.underlineCased()
}
}
class Student: Person {
var mathScore: Int = 0
// Person的kj_modelKey会继承下来给Student使用
// `mathScore` -> `math_score`
}
let nick_ame = "Jack"
let math_score = 96
let json: [String: Any] = ["nick_name": nick_ame, "math_score": math_score]
let person = json.kj.model(Person.self)
XCTAssert(person.nickName == nick_ame)
let student = json.kj.model(Student.self)
XCTAssert(student.nickName == nick_ame)
XCTAssert(student.mathScore == math_score)
重写
// 子类可以重写父类的kj_modelKey方法，在父类实现的基础上加一些自己的需求
class Person: Convertible {
var name: String = ""
required init() {}
func kj_modelKey(from property: Property) -> ModelPropertyKey {
// `name` -> `_name_`
return property.name == "name" ? "_name_" : property.name
}
}
class Student: Person {
var score: Int = 0
override func kj_modelKey(from property: Property) -> ModelPropertyKey {
// 调用了`super.kj_modelKey`，在父类的基础上加了对`score`的处理
// `score` -> `_score_`，`name` -> `_name_`
return property.name == "score" ? "_score_" : super.kj_modelKey(from: property)
}
}
let name = "Jack"
let score = 96
let json: [String: Any] = ["_name_": name, "_score_": score]
let person = json.kj.model(Person.self)
XCTAssert(person.name == name)
let student = json.kj.model(Student.self)
XCTAssert(student.name == name)
XCTAssert(student.score == score)
重写 + 覆盖
// 子类可以重写父类的kj_modelKey方法，并完全覆盖父类的实现
class Person: Convertible {
var name: String = ""
required init() {}
func kj_modelKey(from property: Property) -> ModelPropertyKey {
// `name` -> `_name_`
return property.name == "name" ? "_name_" : property.name
}
}
class Student: Person {
var score: Int = 0
override func kj_modelKey(from property: Property) -> ModelPropertyKey {
// 这里并没有调用`super. kj_modelKey`
// 因此`score` -> `_score_`，`name` -> `name`
return property.name == "score" ? "_score_" : property.name
}
}
let personName = "Jack"
let person = ["_name_": personName].kj.model(Person.self)
XCTAssert(person.name == personName)
let studentName = "Rose"
let studentScore = 96
let student = ["name": studentName,
"_score_": studentScore].kj.model(Student.self)
XCTAssert(student.name == studentName)
XCTAssert(student.score == studentScore)
全局配置
// 一旦有需要进行`驼峰` -> `下划线`的映射，有可能整个项目的所有模型都需要进行映射，毕竟整个项目的命名规范是统一的
// 假设项目中有100多个模型，那么就需要实现100多次`kj_modelKey`方法，调用100多次underlineCased方法
// KakaJSON内置了全局配置机制，可以1次配置，就能适用于所有的模型（不管是struct还是class，只要是遵守Convertible协议的模型）
// 全局配置整个项目中只需要配置1次，建议在AppDelegate的didFinishLaunching中配置1次即可
ConvertibleConfig.setModelKey { property in
property.name.kj.underlineCased()
}
// ConvertibleConfig.setModelKey { $0.name.kj.underlineCased() }
class Person: Convertible {
var nickName: String = ""
required init() {}
}
class Student: Person {
var mathScore: Int = 0
}
struct Car: Convertible {
var maxSpeed: Double = 0.0
var name: String = ""
}
let nick_ame = "Jack"
let math_score = 96
let json: [String: Any] = ["nick_name": nick_ame, "math_score": math_score]
let person = json.kj.model(Person.self)
XCTAssert(person.nickName == nick_ame)
let student = json.kj.model(Student.self)
XCTAssert(student.nickName == nick_ame)
XCTAssert(student.mathScore == math_score)
let max_speed = 250.0
let name = "Bently"
let car = ["max_speed": max_speed, "name": name].kj.model(Car.self)
XCTAssert(car.maxSpeed == max_speed)
XCTAssert(car.name == name)
局部配置
// 也可以给某些特定的类型做配置
// 局部配置
// 由于Student继承自Person，所以给Person做的配置，能适用在Student身上
ConvertibleConfig.setModelKey(for: [Person.self, Car.self]) {
property in
property.name.kj.underlineCased()
}
class Person: Convertible {
var nickName: String = ""
required init() {}
}
class Student: Person {
var mathScore: Int = 0
}
struct Car: Convertible {
var maxSpeed: Double = 0.0
var name: String = ""
}
let nick_ame = "Jack"
let math_score = 96
let json: [String: Any] = ["nick_name": nick_ame, "math_score": math_score]
let person = json.kj.model(Person.self)
XCTAssert(person.nickName == nick_ame)
let student = json.kj.model(Student.self)
XCTAssert(student.nickName == nick_ame)
XCTAssert(student.mathScore == math_score)
let max_speed = 250.0
let name = "Bently"
let car = ["max_speed": max_speed, "name": name].kj.model(Car.self)
XCTAssert(car.maxSpeed == max_speed)
XCTAssert(car.name == name)
配置示例1
// 全局配置
ConvertibleConfig.setModelKey { property in
property.name.kj.underlineCased()
}
// Person配置
ConvertibleConfig.setModelKey(for: Person.self) { property in
// `name` -> `_name_`
property.name == "name" ? "_name_" : property.name
}
// Student配置
ConvertibleConfig.setModelKey(for: Student.self) { property in
// `score` -> `_score_`，`name` -> `name`
property.name == "score" ? "_score_" : property.name
}
class Person: Convertible {
var name: String = ""
required init() {}
}
class Student: Person {
var score: Int = 0
}
struct Car: Convertible {
var maxSpeed: Double = 0.0
var name: String = ""
}
let personName = "Jack"
let person = ["_name_": personName].kj.model(Person.self)
XCTAssert(person.name == personName)
let studentName = "Rose"
let studentScore = 96
let student = ["name": studentName,
"_score_": studentScore].kj.model(Student.self)
XCTAssert(student.name == studentName)
XCTAssert(student.score == studentScore)
let max_speed = 250.0
let name = "Bently"
let car = ["max_speed": max_speed, "name": name].kj.model(Car.self)
XCTAssert(car.maxSpeed == max_speed)
XCTAssert(car.name == name)
配置示例2
// 全局配置
ConvertibleConfig.setModelKey { property in
property.name.kj.underlineCased()
}
// Person配置
ConvertibleConfig.setModelKey(for: Person.self) { property in
// `name` -> `_name_`
property.name == "name" ? "_name_" : property.name
}
// Student配置
ConvertibleConfig.setModelKey(for: Student.self) { property in
// `score` -> `_score_`，`name` -> `name`
property.name == "score" ? "_score_" : property.name
}
class Person: Convertible {
var name: String = ""
required init() {}
func kj_modelKey(from property: Property) -> ModelPropertyKey {
// 可以通过ConvertibleConfig获取Person当初的配置
// `name` -> `_name_`
return ConvertibleConfig.modelKey(from: property, Person.self)
}
}
class Student: Person {
var score: Int = 0
override func kj_modelKey(from property: Property) -> ModelPropertyKey {
// `score` -> `score`，`name` -> `name`
return property.name
}
}
struct Car: Convertible {
var maxSpeed: Double = 0.0
var name: String = ""
func kj_modelKey(from property: Property) -> ModelPropertyKey {
// 可以通过ConvertibleConfig获取全局配置
// `maxSpeed` -> `max_speed`
// `name` -> `name`
return ConvertibleConfig.modelKey(from: property)
}
}
/*
当配置了多处modelKey时，它们的优先级从高到低，如下所示（以Student类型为例）
1. 使用Student的kj_modelKey的实现
2. 如果没有1，使用Student的ConvertibleConfig配置
3. 如果没有1\2，使用Student父类的ConvertibleConfig配置
4. 如果没有1\2\3，使用Student父类的父类的ConvertibleConfig配置
5. 如果没有1\2\3\4，使用Student父类的父类的父类的....ConvertibleConfig配置
6. 如果没有1\2\3\4\5，使用全局的ConvertibleConfig配置
*/
// Person、Student、Car都实现了kj_modelKey，因此使用kj_modelKey的实现
let personName = "Jack"
let person = ["_name_": personName].kj.model(Person.self)
XCTAssert(person.name == personName)
let studentName = "Rose"
let studentScore = 96
let student = ["name": studentName,
"score": studentScore].kj.model(Student.self)
XCTAssert(student.name == studentName)
XCTAssert(student.score == studentScore)
let max_speed = 250.0
let name = "Bently"
let car = ["max_speed": max_speed, "name": name].kj.model(Car.self)
XCTAssert(car.maxSpeed == max_speed)
XCTAssert(car.name == name)
复杂的key映射
struct Toy: Convertible {
var price: Double = 0.0
var name: String = ""
}
struct Dog: Convertible {
var name: String = ""
var age: Int = 0
var nickName: String?
var toy: Toy?
func kj_modelKey(from property: Property) -> ModelPropertyKey {
switch property.name {
// 对应dog["toy"]
case "toy": return "dog.toy"
// 对应data[1]["dog"]["name"]
case "name": return "data.1.dog.name"
// 会按顺序映射数组中的每一个key，直到成功为止
// 先映射`nickName`，如果失败再映射`nick_name`
// 如果失败再映射`dog["nickName"]`，如果失败再映射`dog["nick_name"]`
case "nickName": return ["nickName", "nick_name", "dog.nickName", "dog.nick_name"]
default: return property.name
}
}
}
let name = "Larry"
let age = 5
let nickName1 = "Jake1"
let nickName2 = "Jake2"
let nickName3 = "Jake3"
let nickName4 = "Jake4"
let toy = (name: "Bobbi", price: 20.5)
let json: [String: Any] = [
"data": [10, ["dog" : ["name": name]]],
"age": age,
"nickName": nickName1,
"nick_name": nickName2,
"dog": [
"nickName": nickName3,
"nick_name": nickName4,
"toy": ["name": toy.name, "price": toy.price]
]
]
let dog = json.kj.model(Dog.self)
XCTAssert(dog.name == name)
XCTAssert(dog.age == age)
XCTAssert(dog.nickName == nickName1)
XCTAssert(dog.toy?.name == toy.name)
XCTAssert(dog.toy?.price == toy.price)
/*-------------------------------------------------*/
struct Team: Convertible {
var name: String?
var captainName: String?
func kj_modelKey(from property: Property) -> ModelPropertyKey {
switch property.name {
case "captainName": return "captain.name"
default: return property.name
}
}
}
let teamName = "V"
let captainName = "Quentin"
let json: [String: Any] = [
"name": teamName,
"captain.name": captainName,
]
let team = json.kj.model(Team.self)
XCTAssert(team.name == teamName)
XCTAssert(team.captainName == captainName)
/*-------------------------------------------------*/
struct Model: Convertible {
var valueA: String?
var valueB: String?
func kj_modelKey(from property: Property) -> ModelPropertyKey {
switch property.name {
case "valueA": return "a.0.a"
case "valueB": return "b.0.b.0.b"
default: return property.name
}
}
}
let json: [String: Any] = [
"a": [ "l", "u", "o" ],
"b": [
[ "b": [ "x", "i", "u" ] ]
]
]
let model = json.kj.model(Model.self)
XCTAssert(model.valueA == "l")
XCTAssert(model.valueB == "x")
