如何快速将 JSON 字符串转换为 JSON 对象？

Question

我尝试生成 JSON 对象并将其转换为 JSON 字符串，并且该过程已成功放置。但是当我尝试将 JSON 字符串转换为 JSON 对象时，我的真正问题就出现了。当我尝试时，结果是 nil。

func generateJSONObject() {
        let jsonObject = createJSONObject(firstName: firstName[0], middleName: middleName[0], lastName: lastName[0], age: age[0], weight: weight[0])
        print("jsonObject : \(jsonObject)")

        let jsonString = jsonObject.description // convert It to JSON String
        print("jsonString : \(jsonString)")

        let jsonObjectFromString = convertToDictionary(text: jsonString)
        print("jsonObjectFromString : \(String(describing: jsonObjectFromString))")

    }

createJSONObject 函数

// JSON Object creation
    func createJSONObject(firstName: String, middleName: String, lastName: String, age: Int, weight: Int) -> [String: Any] {

        let jsonObject: [String: Any] = [
            "user1": [
                "first_name": firstName,
                "middle_name": middleName,
                "last_name": lastName,
                "age": age,
                "weight": weight
            ]
        ]
        return jsonObject
    }

convertToDictionary 函数

func convertToDictionary(text: String) -> [String: Any]? {
        if let data = text.data(using: .utf8) {
            do {
                return try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]
            } catch {
                print(error.localizedDescription)
            }
        }
        return nil
    }

日志

1. 当我打印 JSON 对象时，我得到了

jsonObject：[“user1”：[“age”：21，“middle_name”：“Lazar”，“last_name”：“V”，“weight”：67，“first_name”：“Alwin”]]

1. 当我打印 JSON String 我得到

   jsonString：[“user1”：[“age”：21，“middle_name”：“Lazar”，“last_name”：“V”，“weight”：67，“first_name”：“Alwin”]]

2. 将JSON 字符串转换为JSON 对象我得到以下错误

   无法读取数据，因为它的格式不正确。

   jsonObjectFromString : 无

我不知道为什么会这样。我想将JSON String 转换为JSON Object，我想解析JSON。

Answer 1

基于讨论

import Foundation

let firstName = "Joe"
let lastName = "Doe"
let middleName = "Mc."
let age = 100
let weight = 45

let jsonObject: [String: [String:Any]] = [
    "user1": [
        "first_name": firstName,
        "middle_name": middleName,
        "last_name": lastName,
        "age": age,
        "weight": weight
    ]
]
if let data = try? JSONSerialization.data(withJSONObject: jsonObject, options: .prettyPrinted),
    let str = String(data: data, encoding: .utf8) {
    print(str)
}

打印

{
  "user1" : {
    "age" : 100,
    "middle_name" : "Mc.",
    "last_name" : "Doe",
    "weight" : 45,
    "first_name" : "Joe"
  }
}

Answer 2

Json必须在Array或Dictionary中，不能只是字符串，所以要创建jsonstring首先需要转换为Data格式，然后再转换为String

   func generateJSONObject() {
       let jsonObject = createJSONObject(firstName: "firstName", middleName: "middleName", lastName: "lastName", age: 21, weight: 82)
       print("jsonObject : \(jsonObject)")

       if let jsonString = convertToJsonString(json: jsonObject), let jsonObjectFromString = convertToDictionary(text: jsonString) {
           print("jsonObjectFromString : \(jsonObjectFromString)")
       }
    }

    func convertToJsonString(json: [String: Any]) -> String? {
        do {
            let jsonData = try JSONSerialization.data(withJSONObject: json, options: .prettyPrinted)
            return String(data: jsonData, encoding: .utf8)
        } catch {
            print(error.localizedDescription)
        }
        return nil
    }