……此处省略一万字
一、UI
界面
二、Encodable 编码
一个最常见的http请求
guard let url = URL(string: "https://jsonplaceholder.typicode.com/posts") else { return }
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
let postDictionary = ["userId":"87",
"id":"787",
"title":"你好啊，小明",
"body":"给我滚出去"]
do {
let jsonBody = try JSONSerialization.data(withJSONObject: postDictionary, options: .prettyPrinted)
request.httpBody = jsonBody
} catch {
}
let session = URLSession.shared
session.dataTask(with: request) { (data, response, error) in
guard let data = data else { return }
do{
let json = try JSONSerialization.jsonObject(with: data, options: .mutableContainers)
print(json)
}catch{
print(error)
}
}.resume()
下面我们在上面的例子中使用Encodable
- 1、创建一个结构体,并且继承Encodable
struct Post: Encodable {
var body: String?
var title: String?
var id: Int
var userId
}
- 2、然后替换掉上面的HttoBody部分代码
...
let post = Post(body: "给我滚出去", title: "你好啊，小明", id: 787, userId: 87)
do {
let jsonBody = try JSONEncoder().encode(user)
request.httpBody = jsonBody
} catch {
}
...
瞬间解放了自己拼接字典的操作，是不是很舒服？
在上面的请求返回中，我们还是使用的最原始的方法，现在改为用Decodable去做
- 1、让User这个struct遵从Decodable这个协议
struct Post: Encodable, Decodable {
var body: String?
var title: String?
var id: Int
var userId: Int
}
- 2、然后修改为如下代码：
let json = try JSONDecoder().decode(Post.self, from: data)
print(json)
parse
OK,到了这里你就知道了Encodable、Decodable的基本用法了。
在实际项目开发中，通常返回的数据不会这么简单，很有可能嵌套很多数据，这个时候如何使用Decodable去解析呢？
二、Decodable
先看下我们要解析的数据：
数据
根据上面的json数据，我们定义了如下的结构体
struct User: Decodable {
var id: Int
var name: String
var username: String
var email: String
var phone: String
var website: String
var company: [String: String]
}
我并没有定义address，因为这个里面还嵌套了一层，后面会写到的。
OK，开始请求数据
guard let url = URL(string: "https://jsonplaceholder.typicode.com/users") else { return }
let session = URLSession.shared
session.dataTask(with: url) { (data, response, error) in
guard let data = data else { return }
do{
//原始解析方法
// let json = try JSONSerialization.jsonObject(with: data, options: .mutableLeaves)
// print(json)
let users = try JSONDecoder().decode([User].self, from: data)
print(users)
}catch{
print(error)
}
}.resume()
然后运行，然后……
意外啦
- 意思就是，得到的数据是一个数组，解码失败啦！！！，如何搞定？
很简单
let users = try JSONDecoder().decode([User].self, from: data)
然后运行效果如下：
解析数据
- 密密麻麻的数据不便于查看，接下来我们先只打印company
let users = try JSONDecoder().decode([User].self, from: data)
for user in users{
print(user.company)
}
["catchPhrase": "Multi-layered client-server neural-net", "name": "Romaguera-Crona", "bs": "harness real-time e-markets"]
["catchPhrase": "Proactive didactic contingency", "name": "Deckow-Crist", "bs": "synergize scalable supply-chains"]
["catchPhrase": "Face to face bifurcated interface", "name": "Romaguera-Jacobson", "bs": "e-enable strategic applications"]
["catchPhrase": "Multi-tiered zero tolerance productivity", "name": "Robel-Corkery", "bs": "transition cutting-edge web services"]
["catchPhrase": "User-centric fault-tolerant solution", "name": "Keebler LLC", "bs": "revolutionize end-to-end systems"]
["catchPhrase": "Synchronised bottom-line interface", "name": "Considine-Lockman", "bs": "e-enable innovative applications"]
["catchPhrase": "Configurable multimedia task-force", "name": "Johns Group", "bs": "generate enterprise e-tailers"]
["catchPhrase": "Implemented secondary concept", "name": "Abernathy Group", "bs": "e-enable extensible e-tailers"]
["catchPhrase": "Switchable contextually-based project", "name": "Yost and Sons", "bs": "aggregate real-time technologies"]
["catchPhrase": "Centralized empowering task-force", "name": "Hoeger LLC", "bs": "target end-to-end models"]
这个时候我们发现，我们得到的还不是一个对象，然后我想一步到位把company也给解析出来如何做呢？
-
很简单，定义一个结构体，然后遵从Decodable协议
struct Company: Decodable {
var name: String
var catchPhrase: String
var bs: String
}
把User的结构体的company重新赋值
var company: Company
//只打印公司名称
for user in users{
print(user.company.name)
}
- 然后在运行一次，神奇的事情就发生了：
Romaguera-Crona
Deckow-Crist
Romaguera-Jacobson
Robel-Corkery
Keebler LLC
Considine-Lockman
Johns Group
Abernathy Group
Yost and Sons
Hoeger LLC
现在company也可以完成解析，就还剩下多重嵌套的Address还没写了。
通过上面的代码可以知道，可以嵌套解析，所以address就是套娃操作了
- 1、定义结构体
struct Address: Decodable {
var street: String
var suite: String
var city: String
var zipcode: String
var geo: Geo
}
struct Geo: Decodable {
var lat: String
var lng: String
}
在User结构体中新增
var address: Address
然后？然后就写完啦，为了测试，我们打印user.address.geo.lat
解析出来啦
OK，到这里基本上就阔以不使用第三方去解析数据啦！！！