以编程方式快速编写 JSON 文件

Posted 2023-03-15

【中文标题】以编程方式快速编写 JSON 文件

【英文标题】：Writing JSON file programmatically swift

【发布时间】：2017-03-02 08:49:18

【问题描述】：

我正在制作测验应用程序，我想从服务器下载 JSON 文件中的问题，解析它并制作我将呈现的问题对象。我这样做了，现在我想制作一个将创建 JSON 文件并将其上传到服务器的应用程序，我希望它看起来像这样

我将从文本字段中获取所有信息并将其保存在这样的 JSON 文件中（带有 oder 值）

    [

    "question":"If you want to create a custom class which can be displayed on the view, you can subclass UIView.",
    "answers":["True", "False"],
    "correctIndex":0,
    "module":3,
    "lesson":0,
    "feedback":"Subclassing UIView gives your class the methods and properties of a basic view which can be placed onto the view."

 ]

swift 中是否有任何具有我可以使用的功能的框架？ 还是我必须手动制作？如果手动如何保存 JSON 文件？

【问题讨论】：

JSONSerialization!

你应该看看 SwiftyJSON (github.com/SwiftyJSON/SwiftyJSON)

我想这可能对你有帮助：http://***.com/questions/28768015/how-to-save-an-array-as-a-json-file-in-swift

alamofire 框架是最好的选择:)

【参考方案1】：

您可以为此目的使用 JSONSerialization 类。请参阅下面在 Playground 中编写的代码 sn-p

import Foundation

// Dictionary containing data as provided in your question.
var dictonary : [String : Any] = ["question":"If you want to create a custom class which can be displayed on the view, you can subclass UIView.",
                                  "answers":["True", "False"],
                                  "correctIndex":0,
                                  "module":3,
                                  "lesson":0,
                                  "feedback":"Subclassing UIView gives your class the methods and properties of a basic view which can be placed onto the view."
                                 ]


if let jsonData = try JSONSerialization.data(withJSONObject: dictonary, options: .init(rawValue: 0)) as? Data

    // Check if everything went well
    print(NSString(data: jsonData, encoding: 1)!)

    // Do something cool with the new JSON data

如果您在 Xcode Playground 中运行此代码，您可以看到以 JSON 格式打印的数据 获得 JSON 后，您可以使用您选择的网络库将数据发送到服务器。

【讨论】：

请建议将 prettyprinted JSON 上传到服务器。服务器不在乎，文件包含一堆不必要的空格和换行符。

您可以只写options: [] 或完全省略, options: .init(rawValue: 0)。没有选项是默认设置。

【参考方案2】：

斯威夫特 3/4

将 Json 数据保存在本地文件中

func saveUploadedFilesSet(fileName:[String : Any]) 
        let file: FileHandle? = FileHandle(forWritingAtPath: "\(fileName).json")

        if file != nil 
            // Set the data we want to write
            do
                if let jsonData = try JSONSerialization.data(withJSONObject: fileName, options: .init(rawValue: 0)) as? Data
                
                    // Check if everything went well
                    print(NSString(data: jsonData, encoding: 1)!)
                    file?.write(jsonData)

                    // Do something cool with the new JSON data
                
            
            catch 

            
            // Write it to the file

            // Close the file
            file?.closeFile()
        
        else 
            print("Ooops! Something went wrong!")
        
    

斯威夫特 3/4 从本地文件中获取 json 数据

func getUploadedFileSet(filename:String) 
    if let path = Bundle.main.path(forResource: "assets/\(filename)", ofType: "json") 
        do 
            let data = try Data(contentsOf: URL(fileURLWithPath: path), options: .mappedIfSafe)
            let jsonResult = try JSONSerialization.jsonObject(with: data, options: .mutableLeaves)
            if let jsonResult = jsonResult as? Dictionary<String, AnyObject>, let person = jsonResult["person"] as? [Any] 
                // do stuff
            
         catch let error 
            print("parse error: \(error.localizedDescription)")
        
     else 
        print("Invalid filename/path.")
    

否则您可以将 [String:Any] 对象转换为 json

import Foundation

// Dictionary containing data as provided in your question.
var dictonary : [String : Any] = ["question":"If you want to create a custom class which can be displayed on the view, you can subclass UIView.",
                                  "answers":["True", "False"],
                                  "correctIndex":0,
                                  "module":3,
                                  "lesson":0,
                                  "feedback":"Subclassing UIView gives your class the methods and properties of a basic view which can be placed onto the view."
                                 ]


if let jsonData = try JSONSerialization.data(withJSONObject: dictonary, options: .init(rawValue: 0)) as? Data

    // Check if everything went well
    print(NSString(data: jsonData, encoding: 1)!)

    // Do something cool with the new JSON data

【参考方案3】：

试试这个 Playground file

斯威夫特 3

let jsonString = "[" +
    "" +
    "    \"question\":\"If you want to create a custom class which can be displayed on the view, you can subclass UIView.\"," +
    "    \"answers\":[\"True\", \"False\"]," +
    "    \"correctIndex\":0," +
    "    \"module\":3," +
    "    \"lesson\":0," +
    "    \"feedback\":\"Subclassing UIView gives your class the methods and properties of a basic view which can be placed onto the view.\"" +
    "" +
" ]"


// convert String to NSData
let dataFromString: Data? = jsonString.data(using: String.Encoding.utf8)


guard let data = dataFromString else 
    print("Error")
    return


do 
    let parsedData = try JSONSerialization.jsonObject(with: data, options: []) as! [[String:Any]]
 catch let error 
    print(error)