json - 如何使用响应数据解码值

Question

投资组合模型

public struct PortfolioModel : Decodable {

    let symbols_requested: Int
    let symbols_returned: Int
    let data: [Portfolio]
}
struct Portfolio : Decodable {

    let stockValue : StockValue
    let todaysLowHigh : HighLowValue
    let fiftyTwoWeekLowHigh : HighLowValue
    let priceBandLowHigh : HighLowValue
    let stockPriceValue : StockPriceValue
    let stockStatistics : StockStatistics

    struct StockValue: Decodable {

        let stockName: String?
        let stockCurrentPrice: String?
        let stockChangeValue : String?
        let stockVolume : String?
        let stockDateValue : String?
    }

    struct HighLowValue: Decodable {

        let minimumValue : String?
        let maximumValue : String?
        let currentValue : String?
    }

    struct StockPriceValue: Decodable {

        let bidPriceValue : String?
        let bidQtyValue : String?
        let offerPriceValue : String?
        let offerOtyValue : String?
        let openPriceValue : String?
    }

    struct  StockStatistics : Decodable{

        let stockMarketCapValue : String?
        let stockDividendValue : String?
        let stockDivYield : String?
        let stockfaceValue :String?
        let stockMarketLot : String?
        let stockIndustryPE : String?

        let stockEPSTTM  : StandColidate
        let stockPC : StandColidate
        let stockPE : StandColidate
        let stockPriceBook : StandColidate
        let stockBookValue : StandColidate

        let stockDeliverables : String?
    }

    struct StandColidate : Decodable{

        let standalone : String?
        let consolidate: String?
    }
}

Web服务客户端服务器

    .responseJSON { response in
        switch response.result {
        case .success:
            let decoder = JSONDecoder()
            decoder.dateDecodingStrategy = .iso8601
            do {

                let result = try decoder.decode(PortfolioModel.self, from: response.data!)
                self.portfolio = result.data
                print(result.data)
                completion(self.portfolio)

                return
            }
                catch {
                    MKProgress.hide()
                    print("Decoding error:", error)
                }
            case .failure(let error):
                MKProgress.hide()
                print("Request failed with error: \(error)")
            }

服务器响应

{
    "symbols_requested": 1,
    "symbols_returned": 1,
    "data": [
        {
            "symbol": "AAPL",
            "name": "Apple Inc.",
            "currency": "USD",
            "price": "196.85",
            "price_open": "196.45",
            "day_high": "197.10",
            "day_low": "195.93",
            "52_week_high": "233.47",
            "52_week_low": "142.00",
            "day_change": "1.16",
            "change_pct": "0.59",
            "close_yesterday": "195.69",
            "market_cap": "926316741610",
            "volume": "8909408",
            "volume_avg": "28596757",
            "shares": "4715280000",
            "stock_exchange_long": "NASDAQ Stock Exchange",
            "stock_exchange_short": "NASDAQ",
            "timezone": "EDT",
            "timezone_name": "America/New_York",
            "gmt_offset": "-14400",
            "last_trade_time": "2019-04-05 12:28:19"
        }
    ]
}

我收到 catch block 错误消息

Decoding error: keyNotFound(CodingKeys(stringValue: "stockValue", intValue: nil), Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "data", intValue: nil), _JSONKey(stringValue: "Index 0", intValue: 0)], debugDescription: "No value associated with key CodingKeys(stringValue: \"stockValue\", intValue: nil) (\"stockValue\").", underlyingError: nil))

我知道它的解码方式是错误的!所有字符串值都放入单个struct Portfolio但是我可以通过以下ProtfolioModel实现它吗？

Answer 1

错误非常明显:键data的数组中没有键stockValue。无论如何，该数组中没有表示结构的字典。

这两个结构与 JSON 匹配，在 quicktype.io 上快速创建

public struct PortfolioModel : Decodable {

    let symbolsRequested: Int
    let symbolsReturned: Int
    let data: [Portfolio]

    enum CodingKeys: String, CodingKey {
        case symbolsRequested = "symbols_requested"
        case symbolsReturned = "symbols_returned"
        case data = "data"
    }
}

struct Portfolio: Codable {
    let symbol, name, currency, price, priceOpen, dayHigh, dayLow: String
    let the52_WeekHigh, the52_WeekLow, dayChange, changePct, closeYesterday, marketCap: String
    let volume, volumeAvg, shares, stockExchangeLong, stockExchangeShort, timezone: String
    let timezoneName, gmtOffset, lastTradeTime: String

    enum CodingKeys: String, CodingKey {
        case symbol = "symbol", name = "name", currency = "currency"
        case price = "price", priceOpen = "price_open", dayHigh = "day_high"
        case dayLow = "day_low", the52_WeekHigh = "52_week_high", the52_WeekLow = "52_week_low"
        case dayChange = "day_change", changePct = "change_pct", closeYesterday = "close_yesterday"
        case marketCap = "market_cap", volume = "volume", volumeAvg = "volume_avg", shares = "shares"
        case stockExchangeLong = "stock_exchange_long", stockExchangeShort = "stock_exchange_short"
        case timezone = "timezone", timezoneName = "timezone_name", gmtOffset = "gmt_offset", lastTradeTime = "last_trade_time"
    }
}