JSONDecoder出现Swift可编码JSON解析错误

Question

我试图用Codable处理JSON，但当我用JSONDecoder((.dedecode.解码时出现解析错误

{
"data": [
{
"id": "90",
"symbol": "BTC",
"name": "Bitcoin",
"nameid": "bitcoin",
"rank": 1,
"price_usd": "50513.75",
"percent_change_24h": "3.03",
"percent_change_1h": "-0.50",
"percent_change_7d": "-9.91",
"price_btc": "1.00",
"market_cap_usd": "942710364520.73",
"volume24": 70745042591.75044,
"volume24a": 107034995571.4168,
"csupply": "18662452.00",
"tsupply": "18662452",
"msupply": "21000000"
},
{
"id": "80",
"symbol": "ETH",
"name": "Ethereum",
"nameid": "ethereum",
"rank": 2,
"price_usd": "4052.44",
"percent_change_24h": "10.17",
"percent_change_1h": "-0.78",
"percent_change_7d": "17.75",
"price_btc": "0.084812",
"market_cap_usd": "466734637594.73",
"volume24": 53134000887.50444,
"volume24a": 87082811090.79503,
"csupply": "115173595.00",
"tsupply": "115173595",
"msupply": ""
}
],
"info": {
"coins_num": 5949,
"time": 1621022046
}
}

json如上所述，我对所有模型进行了如下编码。

class CoinModel: Codable {
var data: [Coin]?
var info: CoinInfo?

enum CodingKeys: String, CodingKey {
case data
case info
}
}
class CoinInfo: Codable {
var coinsNum: Int?
var time: TimeInterval?

enum CodingKeys: String, CodingKey {
case coinsNum = "coins_num"
case time = "time"
}
}

class Coin: Codable{
var csupply: String?
var id: String?
var marketCapUsd: String?
var msupply: Int?
var name: String?
var nameid: String?
var percentChange1h: String?
var percentChange24h: String?
var percentChange7d: String?
var priceBtc: String?
var priceUsd: String?
var rank: Int?
var symbol: String?
var tsupply: Int?
var volume24: Double?
var volume24a: Double?
enum CodingKeys: String, CodingKey {
case csupply = "csupply"
case id = "id"
case marketCapUsd = "market_cap_usd"
case msupply = "msupply"
case name = "name"
case nameid = "nameid"
case percentChange1h = "percent_change_1h"
case percentChange24h = "percent_change_24h"
case percentChange7d = "percent_change_7d"
case priceBtc = "price_btc"
case priceUsd = "price_usd"
case rank = "rank"
case symbol = "symbol"
case tsupply = "tsupply"
case volume24 = "volume24"
case volume24a = "volume24a"
}
}

我的网络功能如下。

URLSession.shared.dataTask(with: url) { (data, response, error) in
guard error == nil else {
completion(.failure(error!))
return
}

guard let data = data else {
completion(.failure(error ?? NSError()))
return
}

let json = try? JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String: Any]

guard let model = try? JSONDecoder().decode(CoinModel.self, from: data) else {
completion(.success([]))
return
}

completion(.success(model.data ?? []))

}.resume()

正如我之前所说，json对象不是nil，我得到如下结果。

[({
csupply = "435032301.00";
id = 33285;
"market_cap_usd" = "435337535.24";
msupply = "";
name = "USD Coin";
nameid = "usd-coin";
"percent_change_1h" = "0.01";
"percent_change_24h" = "0.19";
"percent_change_7d" = "0.16";
"price_btc" = "0.000023";
"price_usd" = "1.00";
rank = 100;
symbol = USDC;
tsupply = 435032301;
volume24 = "11520659193.03477";
volume24a = "13684311331.83874";
}
)
, "info": {
"coins_num" = 5952;
time = 1621160044;
}]

我可以用JSONSerialization处理JSON，但我找不到JSONDecoder方式解析错误的任何原因。我想我没有看到问题。感谢您的建议和帮助。

编辑：

我在Codable类中进行了几次更改，解决了这个问题。在描述id、csupply等的模型时，我犯了一个错误。

var csupply: String?
var msupply: String?
var tsupply: String?

Answer 1

在定义对象时有几个错误。例如，您定义了id，msupply是一个整数，但它们是字符串。您已经将volume24和volume24a定义为字符串，但它们不是。你需要解决所有这些问题，这可能就是你不能解析它的原因

所有定义错误的参数都是id、mSupply、volume24、volume24a、tSupply，用于硬币对象，对于info对象，您也需要将time转换为Int。