- 比如客户端想要的是Date类型，服务器返回的可能是字符串
"2018-08-08 08:08:08.888"或者"2018/08/08 08:08:08.888" - 像上述情况，KakaJSON内部是无法自动转换的，但提供了值过滤机制，允许开发者对JSON值进行自定义处理
日期处理
// 这2个DateFormatter仅仅为了举例子而写的，具体细节根据自己需求而定
private let date1Fmt: DateFormatter = {
let fmt = DateFormatter()
fmt.dateFormat = "yyyy-MM-dd"
return fmt
}()
private let date2Fmt: DateFormatter = {
let fmt = DateFormatter()
fmt.dateFormat = "yyyy-MM-dd HH:mm:ss.SSS"
return fmt
}()
struct Student: Convertible {
var date1: Date?
var date2: NSDate?
// 实现kj_modelValue方法
// 会传入属性`property`以及这个属性对应的JSON值`jsonValue`
// 返回值是你希望最后设置到模型属性上的值
// 如果返回`jsonValue`，代表不做任何事，交给KakaJSON内部处理
// 如果返回`nil`，代表忽略这个属性，KakaJSON不会给这个属性设值（属性会保留它的默认值）
func kj_modelValue(from jsonValue: Any?, _ property: Property) -> Any? {
switch property.name {
// 如果jsonValue是字符串，就直接转成Date
case "date1": return (jsonValue as? String).flatMap(date1Fmt.date)
// 如果jsonValue是字符串，就直接转成Date
// 由于NSDate与Date之间是可以桥接转换的，所以返回Date给NSDate属性也是没有问题的
case "date2": return (jsonValue as? String).flatMap(date2Fmt.date)
default: return jsonValue
}
}
}
let date1 = "2008-09-09"
let date2 = "2011-11-12 14:20:30.888"
let json: [String: Any] = [
"date1": date1,
"date2": date2
]
let student = json.kj.model(Student.self)
// 将Date\NSDate转回字符串进行比较
XCTAssert(student.date1.flatMap(date1Fmt.string) == date1)
XCTAssert(student.date2.flatMap(date2Fmt.string) == date2)
不确定类型
// 有时候服务器返回的某个字段的内容类型可能是不确定的
// 客户端可以先标记为Any类型或者AnyObject类型或者协议类型等不确定类型
struct Person: Convertible {
var name: String = ""
var pet: Any?
func kj_modelValue(from jsonValue: Any?, _ property: Property) -> Any? {
// 如果不是`pet`属性，就按照默认处理
if property.name != "pet" { return jsonValue }
// 如果是`pet`属性，并且`jsonValue`是个字典，就转换为`Dog`模型实例
// 具体判断逻辑可以根据实际开发需求而定
return (jsonValue as? [String: Any])?.kj.model(Dog.self)
}
}
struct Dog: Convertible {
var name: String = ""
var weight: Double = 0.0
}
let json: [String: Any] = [
"name": "Jack",
"pet": ["name": "Wang", "weight": 109.5]
]
let person = json.kj.model(Person.self)
XCTAssert(person.name == "Jack")
let pet = person.pet as? Dog
XCTAssert(pet?.name == "Wang")
XCTAssert(pet?.weight == 109.5)
/*---------------------------------------------*/
class Book: Convertible {
var name: String = ""
var price: Double = 0.0
required init() {}
}
struct Person: Convertible {
var name: String = ""
// [AnyObject]、[Convertible]、NSArray、NSMutableArray
var books: [Any]?
func kj_modelValue(from jsonValue: Any?,
_ property: Property) -> Any? {
if property.name != "books" { return jsonValue }
// if books is `NSMutableArray`, neet convert `Array` to `NSMutableArray`
// because `Array` to `NSMutableArray` is not a bridging conversion
return (jsonValue as? [Any])?.kj.modelArray(Book.self)
}
}
let name = "Jack"
let books = [
(name: "Fast C++", price: 666),
(name: "Data Structure And Algorithm", price: 1666)
]
let json: [String: Any] = [
"name": name,
"books": [
["name": books[0].name, "price": books[0].price],
["name": books[1].name, "price": books[1].price]
]
]
let person = json.kj.model(Person.self)
XCTAssert(person.name == name)
XCTAssert(person.books?.count == books.count)
let book0 = person.books?[0] as? Book
XCTAssert(book0?.name == books[0].name)
XCTAssert(book0?.price == Double(books[0].price))
let book1 = person.books?[1] as? Book
XCTAssert(book1?.name == books[1].name)
XCTAssert(book1?.price == Double(books[1].price))
其他例子
struct Student: Convertible {
var age: Int = 0
var name: String = ""
func kj_modelValue(from jsonValue: Any?, _ property: Property) -> Any? {
switch property.name {
// 如果`age`属性的`jsonValue`是整数，就加上5
case "age": return (jsonValue as? Int).flatMap { $0 + 5 }
// 如果`name `属性的`jsonValue`是字符串，就在前面加上`kj_`
case "name": return (jsonValue as? String).flatMap { "kj_" + $0 }
default: return jsonValue
}
}
}
let json: [String: Any] = [
"age": 10,
"name": "Jack"
]
let student = json.kj.model(Student.self)
XCTAssert(student.age == 15)
XCTAssert(student.name == "kj_Jack")
其他实现思路
// 关于值过滤、自定义值处理的逻辑，也可以在模型转换完毕之后进行
struct Student: Convertible {
var age: Int = 0
var name: String = ""
// 实现`kj_didConvertToModel`方法，在这里修改转换之后的属性值
mutating func kj_didConvertToModel(from json: [String: Any]) {
age += 5
name = "kj_" + name
}
}
let json: [String: Any] = [
"age": 10,
"name": "Jack"
]
let student = json.kj.model(Student.self)
XCTAssert(student.age == 15)
XCTAssert(student.name == "kj_Jack")
最后的提示
kj_modelValue也支持ConvertibleConfig配置，用法类似于kj_modelKey，参考第三篇文章