ios 在 Swift 4 中将 Json 字符串转换为 Json 对象

Convert Json string to Json object in Swift 4

提问by Inderpal Singh

I try to convert JSON string to a JSON object but after JSONSerializationthe output is nilin JSON.

我尝试将 JSON 字符串转换为 JSON 对象，但在JSONSerialization输出为nilJSON 之后。

Response String:

响应字符串：

[{\"form_id\":3465,\"canonical_name\":\"df_SAWERQ\",\"form_name\":\"Activity 4 with Images\",\"form_desc\":null}]

I try to convert this string with my code below:

我尝试使用下面的代码转换此字符串：

let jsonString = response.result.value
let data: Data? = jsonString?.data(using: .utf8)
let json = (try? JSONSerialization.jsonObject(with: data, options: [])) as? [String:AnyObject]
 print(json ?? "Empty Data")

回答by Amit

The problem is that you thought your jsonString is a dictionary. It's not.

问题是你认为你的 jsonString 是一本字典。它不是。

It's an arrayof dictionaries. In raw json strings, arrays begin with [and dictionaries begin with {.

这是一个字典数组。在原始 json 字符串中，数组以 开头，[字典以 开头{。

---

---

I used your json string with below code :

我将您的 json 字符串与以下代码一起使用：

let string = "[{\"form_id\":3465,\"canonical_name\":\"df_SAWERQ\",\"form_name\":\"Activity 4 with Images\",\"form_desc\":null}]"
let data = string.data(using: .utf8)!
do {
    if let jsonArray = try JSONSerialization.jsonObject(with: data, options : .allowFragments) as? [Dictionary<String,Any>]
    {
       print(jsonArray) // use the json here     
    } else {
        print("bad json")
    }
} catch let error as NSError {
    print(error)
}

and I am getting the output :

我得到了输出：

[["form_desc": <null>, "form_name": Activity 4 with Images, "canonical_name": df_SAWERQ, "form_id": 3465]]

回答by Patru

Using JSONSerializationalways felt unSwifty and unwieldy, but it is even more so with the arrival of Codablein Swift 4. If you wield a [String:Any]in front of a simple structit will ... hurt. Check out this in a Playground:

使用JSONSerialization总是感觉不灵活和笨拙，但随着CodableSwift 4的到来更是如此。如果你[String:Any]在一个简单的前面使用struct它会......伤害。在操场上看看这个：

import Cocoa

let data = "[{\"form_id\":3465,\"canonical_name\":\"df_SAWERQ\",\"form_name\":\"Activity 4 with Images\",\"form_desc\":null}]".data(using: .utf8)!

struct Form: Codable {
    let id: Int
    let name: String
    let description: String?

    private enum CodingKeys: String, CodingKey {
        case id = "form_id"
        case name = "form_name"
        case description = "form_desc"
    }
}

do {
    let f = try JSONDecoder().decode([Form].self, from: data)
    print(f)
    print(f[0])
} catch {
    print(error)
}

With minimal effort handling this will feel a whole lot more comfortable. Andyou are given a lot more information if your JSON does not parse properly.

用最少的努力处理这会感觉更舒服。如果您的 JSON 解析不正确，您将获得更多信息。

回答by Aviram Netanel

I tried the solutions here, and as? [String:AnyObject]worked for me:

我在这里尝试了解决方案，作为？[String:AnyObject]为我工作：

do{
    if let json = stringToParse.data(using: String.Encoding.utf8){
        if let jsonData = try JSONSerialization.jsonObject(with: json, options: .allowFragments) as? [String:AnyObject]{
            let id = jsonData["id"] as! String
            ...
        }
    }
}catch {
    print(error.localizedDescription)

}

回答by Zain Anjum

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
}

let str = "{\"name\":\"James\"}"
let dict = convertToDictionary(text: str)

回答by Bhavsang Jam

I used below code and it's working fine for me. :

我使用了下面的代码，它对我来说很好用。：

let jsonText = "{\"userName\":\"Bhavsang\"}" var dictonary:NSDictionary?

让 jsonText = "{\"userName\":\"Bhavsang\"}" var dictonary:NSDictionary?

    if let data = jsonText.dataUsingEncoding(NSUTF8StringEncoding) {

        do {
            dictonary =  try NSJSONSerialization.JSONObjectWithData(data, options: [.allowFragments]) as? [String:AnyObject]

            if let myDictionary = dictonary
            {
                 print(" User name is: \(myDictionary["userName"]!)")
            }
        } catch let error as NSError {
            print(error)
        }
    }