如何在 swift 4 中使用可解码解析这种类型的 json 格式?

Question

{
"type": "Success",
"message": "",
"fitting": {
"fitterID": "96ba096c-f0aa-11e7-a67a-76478bc72e4d",
"fitID": "09d399c0-7d74-4578-a138-5f4b02ba2e80",
"leftNotesJSON": "[{"class":"FitNote","text":"Saddle Down","leftfoot":false},{"class":"FitNote","text":"Saddle Down","leftfoot":false},{"class":"FootBottomNote","leftfoot":false}]",
"rightNotesJSON": "[{"s3Bucket":"8190ba10-d310-11e3-9c1a-0800200c9a66","angle":0,"leftfoot":false,"shoulderAngle":0,"hipAngle":0,"s3Key":"FD0F5AE6-8193-4980-AD11-C42FEF064B8B","class":"AngleNote","kneeAngle":0}]"
}
}

Answer 1

您问题中的 json 无效。我将在我的答案中使用以下 json：

let json = """
{
"type": "Success",
"message": "",
"fitting": {
"fitterID": "96ba096c-f0aa-11e7-a67a-76478bc72e4d",
"fitID": "09d399c0-7d74-4578-a138-5f4b02ba2e80",
"leftNotesJSON": [{"class":"FitNote","text":"Saddle Down","leftfoot":false},{"class":"FitNote","text":"Saddle Down","leftfoot":false},{"class":"FootBottomNote","leftfoot":false}],
"rightNotesJSON": [{"s3Bucket":"8190ba10-d310-11e3-9c1a-0800200c9a66","angle":0,"leftfoot":false,"shoulderAngle":0,"hipAngle":0,"s3Key":"FD0F5AE6-8193-4980-AD11-C42FEF064B8B","class":"AngleNote","kneeAngle":0}]
}
}
"""

让我们定义可解码结构：

struct Response: Codable {
let type, message: String
let fitting: Fitting
}
struct Fitting: Codable {
let fitterID, fitID: String
let leftNotesJSON: [LeftNotesJSON]
let rightNotesJSON: [RightNotesJSON]
}
struct LeftNotesJSON: Codable {
let leftNotesJSONClass: String
let text: String?
let leftfoot: Bool
//Define the coding keys since the json contains "class" as a key
enum CodingKeys: String, CodingKey {
case leftNotesJSONClass = "class"
case text, leftfoot
}
}
struct RightNotesJSON: Codable {
let s3Bucket: String
let angle: Int
let leftfoot: Bool
let shoulderAngle, hipAngle: Int
let s3Key, rightNotesJSONClass: String
let kneeAngle: Int
//Define the coding keys since the json contains "class" as a key  
enum CodingKeys: String, CodingKey {
case s3Bucket, angle, leftfoot, shoulderAngle, hipAngle, s3Key
case rightNotesJSONClass = "class"
case kneeAngle
}
}

让我们从 json 中获取数据：

guard let data = json.data(using: .utf8) else {
fatalError("Couldn't get data from json")
}

然后解码

do {
let response = try JSONDecoder().decode(Response.self, from: data)
//Here and now you can use the properties of the response
print(response.type)
print(response.message)
print(response.fitting.fitID)
print(response.fitting.fitterID)
print(response.fitting.leftNotesJSON.map {$0.leftfoot})
print(response.fitting.rightNotesJSON.map{$0.kneeAngle})
} catch {
print(error)
}

Answer 2

首先，您可能必须创建模型，以确认可编码协议。您可以使用任何在线工具来格式化 JSON 和创建模型。在给定的代码响应中，模型将获得解析后的数据。

import Foundation
struct Base : Codable {
let type : String?
let message : String?
let fitting : Fitting?
enum CodingKeys: String, CodingKey {
case type = "type"
case message = "message"
case fitting = "fitting"
}
init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
type = try values.decodeIfPresent(String.self, forKey: .type)
message = try values.decodeIfPresent(String.self, forKey: .message)
fitting = try values.decodeIfPresent(Fitting.self, forKey: .fitting)
}
}

import Foundation
struct Fitting : Codable {
let fitterID : String?
let fitID : String?
let leftNotesJSON : String?
let rightNotesJSON : String?
enum CodingKeys: String, CodingKey {
case fitterID = "fitterID"
case fitID = "fitID"
case leftNotesJSON = "leftNotesJSON"
case rightNotesJSON = "rightNotesJSON"
}
init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
fitterID = try values.decodeIfPresent(String.self, forKey: .fitterID)
fitID = try values.decodeIfPresent(String.self, forKey: .fitID)
leftNotesJSON = try values.decodeIfPresent(String.self, forKey: .leftNotesJSON)
rightNotesJSON = try values.decodeIfPresent(String.self, forKey: .rightNotesJSON)
}
}
let task = URLSession.shared.dataTask(with: <YOUR URL>) { (data, response, error) in
if let data = data {
let jsonDecoder = JSONDecoder()
let responseModel = try jsonDecoder.decode(Base.self, from: data)
}
}
task.resume()