如何在 swift 4.1 和 xcode 9.3 中使用 JSONDecoder 解码嵌套的 JSON 数组和对象？

Posted 2023-03-15

【中文标题】如何在 swift 4.1 和 xcode 9.3 中使用 JSONDecoder 解码嵌套的 JSON 数组和对象？

【英文标题】：How to decode nested JSON array and object with JSONDecoder in swift 4.1 and xcode 9.3?

【发布时间】：2018-05-17 05:23:19

【问题描述】：

我是 iOS 新手，我在解码包含许多嵌套数组和对象的嵌套 JSON 文件时遇到问题。我正在使用 JSONDecoder 进行解码，但在某处我出错或解码不正确。

我的解码器是

let myOrder = try JSONDecoder().decode(MyOrder.self, from: data!)
                    for items in myOrder.OrderDetials 
                        self.orders.append(MyOrders(order_id: items.order_id!, order_ref_number: items.order_ref_number!, cust_mob: items.cust_mob!, store_name: items.store_name!, store_id: items.store_id!, order_details: items.order_details!, order_amount: items.order_amount!, order_status: items.order_status!, order_status_remark: items.order_status_remark!, order_place_at: items.order_place_at!, order_status_change_at: items.order_status_change_at!))
                        print(items.cust_mob!)
                    
                    print(myOrder)

它抛出的错误是

typeMismatch(Swift.Array<Any>, Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "OrderDetials", intValue: nil), _JSONKey(stringValue: "Index 0", intValue: 0), CodingKeys(stringValue: "order_details", intValue: nil)], debugDescription: "Expected to decode Array<Any> but found a string/data instead.", underlyingError: nil))

我的结构是

struct MyOrder: Decodable 
    var OrderDetials: [OrderDetails]


struct OrderDetails: Decodable 
    var order_id: String?
    var order_ref_number: String?
    var cust_mob: String?
    var store_name: String?
    var store_id: String?
    var order_details: OrderItems?
    var order_amount: String?
    var order_status: String?
    var order_status_remark: String?
    var order_place_at: String?
    var order_status_change_at: String?



struct OrderItems: Decodable 
    var allorder: [AllOrder]
    var TaxDetials: [TaxDetails]


    struct AllOrder: Decodable 
        var date_time: String?
        var item: String?
        var name: String?
    
    struct TaxDetails: Decodable 
        var tax_per: String?
        var tax_name: String?
    

和DataModel类

class MyOrders 
    var order_id: String
    var order_ref_number: String
    var cust_mob: String
    var store_name: String
    var store_id: String
    var order_details: OrderItems?
    var order_amount: String
    var order_status: String
    var order_status_remark: String
    var order_place_at: String
    var order_status_change_at: String?

    init(order_id: String, order_ref_number: String, cust_mob: String, store_name: String, store_id: String, order_details: OrderItems?, order_amount: String, order_status: String, order_status_remark: String, order_place_at: String, order_status_change_at: String?) 
        self.order_id = order_id
        self.order_ref_number = order_ref_number
        self.cust_mob = cust_mob
        self.store_name = store_name
        self.store_id = store_id
        self.order_details = order_details
        self.order_amount = order_amount
        self.order_status = order_status
        self.order_status_remark = order_status_remark
        self.order_place_at = order_place_at
        self.order_status_change_at = order_status_change_at
    


class MyItems 
    var item: String
    var name: String
    var price: String

    init(item: String, name: String, price: String) 
        self.item = item
        self.name = name
        self.price = price
    

我的 JSON 是

    "OrderDetials": [
        
            "order_id": "11",
            "order_ref_number": "MM1525235813",
            "cust_mob": "9958324531",
            "store_name": "Moti mahal",
            "store_id": "1",
            "order_details": "'allorder':[\"date_time\":\"\",\"item\":\"2\",\"name\":\"CHICKN ROLL\",\"price\":\"360\"]\"TaxDetials\":[\"tax_per\":\"5\",\"tax_name\":\"CGST & SGST\"]",
            "order_amount": "378.0",
            "order_status": "1",
            "order_status_remark": "New_Order_Place",
            "order_place_at": "2018-05-02 10:06:53",
            "order_status_change_at": null
        
    ]

请有人告诉我如何正确解码或我需要对结构进行哪些更改。

【问题讨论】：

您的“order_details”键的值是字符串，您的结构将其视为数组。您必须根据定义的结构更改“order_details”键的值才能使其工作

您的 order_details 包含 JSON 之类的结构而不是字符串

我试过这样做：“var order_details: String?”还有这个：“var order_details：[OrderItems]？”两者都给出相同的错误。 @Vikky

var order_details: 字符串？正在工作

查看这篇文章，它解释得很好medium.com/@nimjea/json-parsing-in-swift-2498099b78f

【参考方案1】：

OrderDetials 是 Array of Dictionary [[String: String?]] ，而您的 Initial 响应是 Dictionary 也是 order_details 是 Wrong json String 而不是 Dictionary ，所以我们将它解析为字符串，在 Codable 每个字典 @ 987654329@ 转换为Struct 或Class 和[] 是Array

型号：

import Foundation

struct Initial: Codable 
    let orderDetials: [OrderDetial]

    enum CodingKeys: String, CodingKey 
        case orderDetials = "OrderDetials"
    


struct OrderDetial: Codable 
    let orderID, orderRefNumber, custMob, storeName: String
    let storeID, orderDetails, orderAmount, orderStatus: String
    let orderStatusRemark, orderPlaceAt: String
    let orderStatusShangeAt:String?

    enum CodingKeys: String, CodingKey 
        case orderID = "order_id"
        case orderRefNumber = "order_ref_number"
        case custMob = "cust_mob"
        case storeName = "store_name"
        case storeID = "store_id"
        case orderDetails = "order_details"
        case orderAmount = "order_amount"
        case orderStatus = "order_status"
        case orderStatusRemark = "order_status_remark"
        case orderPlaceAt = "order_place_at"
        case orderStatusShangeAt = "order_status_change_at"


    



// MARK: Convenience initializers

extension Initial 
    init(data: Data) throws 
        self = try JSONDecoder().decode(Initial.self, from: data)
    

这样使用：

   if  let initial =  try? Initial.init(data: data)

                for item in initial.orderDetials 
                    print(item.orderAmount)
                    print(item.orderDetails) // here is Wrong format from your Server API
                
           

Order_details 错误

'allorder':["date_time":"","item":"2","name":"CHICKN ROLL","price":"360"]"TaxDetials":["tax_per":"5","tax_name":"CGST & SGST"]

【讨论】：

现在我得到了 orderDetails 作为字符串。我需要使用 JSONSerialization 来访问其中的数据还是 JSONDecoder 会自动执行此操作？

是的，你可以再次解析它，但它也错误地检查了这个'allorder'不是“allorder”

谢谢，实际上 JSON 是由 API 团队生成的，android 团队也使用相同的 JSON 并且它在那里工作，所以我必须使用相同的 JSON。

不，和服务器上的一样。我已经仔细检查了。

好的，所以你的后端开发人员错了，你可以和你的android开发人员核实一下，他可能用任何其他方式格式化这个字符串，但是这个错误的Json和错误的json字符串