使用 Swift 5 解析来自 AP 的 JSON 数据

Question

我正在尝试解析这个json文件

{
    "Global Quote": {
        "01. symbol": "AAPL",
        "02. open": "122.6000",
        "03. high": "123.3500",
        "04. low": "121.5400",
        "05. price": "121.7800",
        "06. volume": "79075988",
        "07. latest trading day": "2020-12-14",
        "08. previous close": "122.4100",
        "09. change": "-0.6300",
        "10. change percent": "-0.5147%"
    } }

我想解析他的 JSON 文本，但不太确定为什么我的结构没有填充这个全局引用对象，而是将其留空。

struct GlobalQuote: Codable{
    
    var symbol: String?
    var open: String?
    var high: String?
    var low: String?
    var price: String?
    var volume: String?
    var latestTradingDay: String?
    var previousClose: String?
    var change: String?
    var changepercent: String?
    
    private enum codingKeys : String, CodingKey {
         case symbol = "01. symbol"
         case open = "02. open"
         case high = "03. high"
        case low = "04. low"
        case price = "05. price"
        case volume = "06.volume"
        case latestTradingDay = "07. latest trading day"
        case previousClose = "08. previous close"
        case change = "09. change"
        case changepercent = "10. change percent"
        
    
      }
    

}

...它在控制台中返回此..

GlobalQuote(symbol: nil, open: nil, high: nil, low: nil, price: nil, volume: nil, latestTradingDay: nil, previousClose: nil, change: nil, changepercent: nil)

...不太确定为什么我没有收到我的数据。

Answer 1

要解码 JSON，您首先需要将

codingKeys

结构体的

GlobalQuote

内部枚举更改为

CodingKeys

。 （大写开头）

然后您需要另一个结构来表示外部 JSON 对象，如下所示：

struct ResponseGlobalQuote: Codable {
    var globalQuote: GlobalQuote
    
    enum CodingKeys: String, CodingKey {
        case globalQuote = "Global Quote"
    }
}

let decoder = JSONDecoder()
do {
    let decoded = try decoder.decode(ResponseGlobalQuote.self, from: data)
    print(decoded)
} catch {
    print(error)
}

或修改您的解码以使用

[String: GlobalQuote]

作为解码类型：

let decoder = JSONDecoder()
do {
    let decoded = try decoder.decode([String: GlobalQuote].self, from: Data(jsonString.utf8))
    print(decoded.values.first)
} catch {
    print(error)
}