ASP.Net Core 從外部 API 導入 JSON

Question

我是 .NET Core 主頁的新手，有人可以指導我完成此操作。

我需要向這個 url 發出請求並將數據保存到數據庫中： url: https://covid19.mathdro.id/api

JSON 輸出如下所示：

{"confirmed":{"value":303001,"detail":"https://covid19.mathdro.id/api/confirmed"},"recovered":{"value":91669,"detail":"https://covid19.mathdro.id/api/recovered"},"deaths":{"value":12762,"detail":"https://covid19.mathdro.id/api/deaths"},"dailySummary":"https://covid19.mathdro.id/api/daily","dailyTimeSeries":{"pattern":"https://covid19.mathdro.id/api/daily/[dateString]","example":"https://covid19.mathdro.id/api/daily/2-14-2020"},"image":"https://covid19.mathdro.id/api/og","source":"https://github.com/mathdroid/covid19","countries":"https://covid19.mathdro.id/api/countries","countryDetail":{"pattern":"https://covid19.mathdro.id/api/countries/[country]","example":"https://covid19.mathdro.id/api/countries/USA"},"lastUpdate":"2020-03-21T20:13:21.000Z"}

型號：總計

public class Total
{
    [Key]
    public int Id { get; set; }
    [Column(TypeName = "int")]
    [Required]
    public string Confirmed { get; set; }
    [Column(TypeName = "int")]
    [Required]
    public string Recovered { get; set; }
    [Column(TypeName = "int")]
    [Required]
    public string Deaths { get; set; }
    [Column(TypeName = "datetime2")]
    [Required]
    public string LastUpdated { get; set; }
}

我的進口型號：

client.BaseAddress = new Uri("https://covid19.mathdro.id/api");
var response = await client.GetAsync($"");
response.EnsureSuccessStatusCode();
var stringResult = await response.Content.ReadAsStringAsync();

我被困在這里，無法繼續。 如何獲取數據，我只需要：確認、恢復、死亡和上次更新

請。 任何人在這里幫助...

Answer 1

您需要將JSON轉換為Class Object 。 您可以使用NewtonSoft.Json獲取這樣的數據

using (var client = new HttpClient())
{
  string url = string.Format("https://covid19.mathdro.id/api");
  var response = client.GetAsync(url).Result;

  string responseAsString = await response.Content.ReadAsStringAsync();
  result = JsonConvert.DeserializeObject<CovidResult>(responseAsString);
}

public class CovidResult
{
   [JsonProperty("confirmed")]
   public ValueModel Confirmed { get; set; }
   [JsonProperty("recovered")]
   public ValueModel Recovered { get; set; }
   [JsonProperty("deaths")]
   public ValueModel Deaths { get; set; }
}

public class ValueModel
{
   [JsonProperty("value")]
   public int Value { get; set; }
}

你可以 fork 或下載這個 repo： https : //github.com/fatihyildizhan/CoronaParser

Answer 2

你的模態應該是

public class Total
{
    public Confirmed confirmed { get; set; }
    public Recovered recovered { get; set; }
    public Deaths deaths { get; set; }
    public string dailySummary { get; set; }
    public DailyTimeSeries dailyTimeSeries { get; set; }
    public string image { get; set; }
    public string source { get; set; }
    public string countries { get; set; }
    public CountryDetail countryDetail { get; set; }
    public DateTime lastUpdate { get; set; }
}

public class Confirmed
{
    public int value { get; set; }
    public string detail { get; set; }
}

public class Recovered
{
    public int value { get; set; }
    public string detail { get; set; }
}

public class Deaths
{
    public int value { get; set; }
    public string detail { get; set; }
}

public class DailyTimeSeries
{
    public string pattern { get; set; }
    public string example { get; set; }
}

public class CountryDetail
{
    public string pattern { get; set; }
    public string example { get; set; }
}

如果stringResult有一個實際值，你所要做的就是：

JsonConvert.DeserializeObject<Total>(stringResult);

此外，當對模態有疑問時，您可以隨時使用http://json2csharp.com/

Answer 3

我建議你使用 JSon.NET 又名 Newtonsoft。 您可以從 nuget 包管理器添加它。 這是將傳入的 json 數據映射到自定義類 Total 的代碼。 只需添加您的類構造函數，它將 json 數據作為字符串類型的參數，並且我添加了一種方法來縮短代碼

public class Total {

    public Total(string json) {
        JObject jObject = JObject.Parse(json);
        Confirmed = GetStringFromJToken(jObject, "confirmed");
        Recovered = GetStringFromJToken(jObject, "recovered");
        Deaths = GetStringFromJToken(jObject, "deaths");

        LastUpdated = (string)jObject["lastUpdate"];
    }

    private string GetStringFromJToken(JObject jObject, string key) {
        JToken keyToken = jObject[key];
        return (string)keyToken["value"];
    }

    [Key]
    public int Id { get; set; }
    [Column(TypeName = "int")]
    [Required]
    public string Confirmed { get; set; }
    [Column(TypeName = "int")]
    [Required]
    public string Recovered { get; set; }
    [Column(TypeName = "int")]
    [Required]
    public string Deaths { get; set; }
    [Column(TypeName = "datetime2")]
    [Required]
    public string LastUpdated { get; set; }
}