尝试在 swift 中使用 URLSession 解析 JSON 时出错
Error trying to parse JSON using URLSession in swift
我正在尝试从 http
地址解析测试 JSON
,但我收到一条错误消息
"No value associated with key CodingKeys(stringValue: \"name\", intValue: nil)
JSON
看起来像这样。它已经过验证,所以它应该可以正常工作:
{
"work": [
{
"name": "Jocke",
"job": "Developer",
"date": "1985-12-30T00:00:00+0000",
"best_book": {
"id": 33245,
"title": "DiscWorld",
"author": {
"id": 345,
"name": "Terry Prattchet"
}
}
},
{
"name": "Bob",
"job": "Construction worker",
"date": "2010-01-30T00:00:00+0000",
"best_book": {
"id": 375802,
"title": "Ender's Game (Ender's Saga, #1)",
"author": {
"id": 589,
"name": "Orson Scott Card"
}
}
}
]
}
代码如下所示:
struct People: Codable {
let name: String
let job: String
enum OuterKey: String, CodingKey {
case work = "work"
}
enum codingKeys: String, CodingKey {
case name = "name"
case job = "job"
}
init(decoder: Decoder) throws {
let outerContainer = try decoder.container(keyedBy: OuterKey.self)
let innerContainer = try outerContainer.nestedContainer(keyedBy: CodingKeys.self, forKey: .work)
self.name = try innerContainer.decode(String.self, forKey: .name)
self.job = try innerContainer.decode(String.self, forKey: .job)
}
}
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
guard let url = URL(string: "https://api.myjson.com/bins/fe2eo") else { return }
URLSession.shared.dataTask(with: url) { (data, response, error) in
guard let data = data else { return }
do {
let jsonDecoder = JSONDecoder()
jsonDecoder.keyDecodingStrategy = .convertFromSnakeCase
let decodedJson = try! jsonDecoder.decode([People].self, from: data)
}
}.resume()
}
}
我现在只是想掌握前两个 keys
,看看它是否有效。但它甚至没有超过 name
.
你的apireturns
[{"firstName":"Jocke","job":"developer"},{"firstName":"Anna","job":"construction"},{"firstName":"Peter","job":"pilot"}]
do {
let jsonDecoder = JSONDecoder()
let decodedJson = try jsonDecoder.decode([People].self, from: data)
}
catch {
print(error)
}
struct People: Codable {
let firstName, job: String
}
试试这个
struct Work:Codeable {
let work:[People]
}
struct People: Codable {
let name: String
let job: String
}
do {
let jsonDecoder = JSONDecoder()
let decodedJson = try jsonDecoder.decode(Work.self, from: data)
}
catch {
print(error)
}
如果您与 json 键同名则不需要使用 codingkeys
我正在尝试从 http
地址解析测试 JSON
,但我收到一条错误消息
"No value associated with key CodingKeys(stringValue: \"name\", intValue: nil)
JSON
看起来像这样。它已经过验证,所以它应该可以正常工作:
{
"work": [
{
"name": "Jocke",
"job": "Developer",
"date": "1985-12-30T00:00:00+0000",
"best_book": {
"id": 33245,
"title": "DiscWorld",
"author": {
"id": 345,
"name": "Terry Prattchet"
}
}
},
{
"name": "Bob",
"job": "Construction worker",
"date": "2010-01-30T00:00:00+0000",
"best_book": {
"id": 375802,
"title": "Ender's Game (Ender's Saga, #1)",
"author": {
"id": 589,
"name": "Orson Scott Card"
}
}
}
]
}
代码如下所示:
struct People: Codable {
let name: String
let job: String
enum OuterKey: String, CodingKey {
case work = "work"
}
enum codingKeys: String, CodingKey {
case name = "name"
case job = "job"
}
init(decoder: Decoder) throws {
let outerContainer = try decoder.container(keyedBy: OuterKey.self)
let innerContainer = try outerContainer.nestedContainer(keyedBy: CodingKeys.self, forKey: .work)
self.name = try innerContainer.decode(String.self, forKey: .name)
self.job = try innerContainer.decode(String.self, forKey: .job)
}
}
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
guard let url = URL(string: "https://api.myjson.com/bins/fe2eo") else { return }
URLSession.shared.dataTask(with: url) { (data, response, error) in
guard let data = data else { return }
do {
let jsonDecoder = JSONDecoder()
jsonDecoder.keyDecodingStrategy = .convertFromSnakeCase
let decodedJson = try! jsonDecoder.decode([People].self, from: data)
}
}.resume()
}
}
我现在只是想掌握前两个 keys
,看看它是否有效。但它甚至没有超过 name
.
你的apireturns
[{"firstName":"Jocke","job":"developer"},{"firstName":"Anna","job":"construction"},{"firstName":"Peter","job":"pilot"}]
do {
let jsonDecoder = JSONDecoder()
let decodedJson = try jsonDecoder.decode([People].self, from: data)
}
catch {
print(error)
}
struct People: Codable {
let firstName, job: String
}
试试这个
struct Work:Codeable {
let work:[People]
}
struct People: Codable {
let name: String
let job: String
}
do {
let jsonDecoder = JSONDecoder()
let decodedJson = try jsonDecoder.decode(Work.self, from: data)
}
catch {
print(error)
}
如果您与 json 键同名则不需要使用 codingkeys