Swift iOS : 解析json-白红宇

典型的前台后台的交互操作，几乎都是这样的：

访问后台服务API

然后解析它返回的JSON

使用Alamofire，它的扩展AlamofireObjectMapper可以把HTTP访问获得的结果转换为json对象，使用ObjectMapper可以把json对象和swift对象做一个映射。

如下案例，访问cnodejs.org提供的API，并转换返回json为swift对象，并且打印验证：

import UIKitimport Alamofireimport AlamofireObjectMapperimport ObjectMapper@UIApplicationMainclass AppDelegate: UIResponder, UIApplicationDelegate,URLSessionDelegate {    var window: UIWindow?    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {        foo()        return true    }    func foo(){        let URL = "https://cnodejs.org/api/v1/topics?page=2"        Alamofire.request(URL).responseObject { (response: DataResponse
    
     ) in            let topics = response.result.value            print(topics?.success)            print(topics?.data?.count)            if let item = topics?.data {                for it in item {                    print(it.id)                    print(it.author?.avatar_url)                    print(it.tab)                    return                }            }        }    }}class Topics: Mappable {    var success: Bool?    var data : [Topic]?    required init?(map: Map){    }    func mapping(map: Map) {        success <- map["success"]        data <- map["data"]    }}//content title last_reply_at good top reply_count visit_count create_at author{loginname,avatar_url}class Author : Mappable{    var loginname: String?    var avatar_url: String?    required init?(map: Map){    }    func mapping(map: Map) {        loginname <- map["loginname"]        avatar_url <- map["avatar_url"]    }}class Topic: Mappable {    var id: String?    var author_id : String?    var tab : String?    var content : String?    var title : String?    var last_reply_at : String?    var good : String?    var top : String?    var reply_count : String?    var visit_count : String?    var create_at : String?    var author : Author?    required init?(map: Map){    }    func mapping(map: Map) {        id <- map["id"]        author_id <- map["author_id"]        content <- map["content"]        title <- map["title"]        last_reply_at <- map["last_reply_at"]        good <- map["good"]        top <- map["top"]        reply_count <- map["reply_count"]        visit_count <- map["visit_count"]        create_at <- map["create_at"]        author <- map["author"]        tab <- map["tab"]    }}复制代码

如果打印结果形如：

Optional(true)Optional(40)Optional("5989cd6c2d4b0af475035399")Optional("59603478a4de5625080fe1cd")Optional("ask")复制代码

说明代码正常运作。