如何使用Newtonsoft反序列化復雜的JSON？（NASAAPINeoFeed）-有解無憂

我是論壇的新手，我有一個問題。

我正在嘗試使用 Newtonsoft 反序列化 NASA API 的 Neo Feed，但出現此錯誤

Newtonsoft.Json.JsonSerializationException：無法將當前 JSON 物件（例如 {"name":"value"}）反序列化為型別 'System.Collections.Generic.IEnumerable1[NasaApi.Models.Near_Earth_Objects]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly. To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List<T>) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object. Path 'links', line 1, position 9. at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent) at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType) at Newtonsoft.Json.JsonSerializer.Deserialize(JsonReader reader, Type objectType) at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings) at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings) at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value) at NasaApi.Services.NearEarthObjectService.GetAllNeos() in C:\Users\santanitaxx1050\Desktop\NasaApi\NasaApi\Services\NearEarthObjectService.cs:line 18 at lambda_method5(Closure , Object ) at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments) at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask1 actionResultValueTask) 在 Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker 呼叫程式, 任務 lastTask, State next, Scope scope, Object state, Boolean isCompleted) 在 Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker。 Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeInnerFilterAsync>g__Awaited|13_0(ControllerActionInvoker 呼叫程式) 在 Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker 的 Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) Rethrow(ActionExecutedContextSealed context) , Task lastTask, State next, Scope 范圍, Object state, Boolean isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|20_0（ResourceInvoker 呼叫程式，Task lastTask，State next，Scope 范圍，Object 狀態，Boolean isCompleted）在 Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0（ResourceInvoker 呼叫程式，Task 任務，IDisposable 范圍）在Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0（端點端點，任務 requestTask，ILogger 記錄器） ) 在 Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context) 在 Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext) 在 Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext,ISwaggerProvider swaggerProvider) 在 Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

HEADERS

Accept: / Host: localhost:7008 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.79 Safari/537.36 :method: GET Accept-Encoding: gzip, deflate, br Accept-Language: es-ES,es;q=0.9 Cache-Control: no-cache postman-token: ec30b624-b8b6-770d-57ce-4b6dcda1ffc2 sec-gpc: 1 sec-fetch-site: none sec-fetch-mode: cors sec-fetch-dest: empty

I tried

public async Task<IEnumerable<Near_Earth_Objects>> GetAllNeos()
{
    var json = await _httpClient.GetStringAsync($"feed?start_date=2021-11-07&end_date=2021-11-10&api_key=Na1sKwJGK1HVeOF4Yx8aLNp4u8ygT5GSSMF26HQ2");
    return JsonConvert.DeserializeObject<IEnumerable<Near_Earth_Objects>>(json);
}

With this JSON

{
"links": {
    "next": "http://www.neowsapp.com/rest/v1/feed?start_date=2021-12-12&end_date=2021-12-15&detailed=false&api_key=Na1sKwJGK1HVeOF4Yx8aLNp4u8ygT5GSSMF26HQ2",
    "prev": "http://www.neowsapp.com/rest/v1/feed?start_date=2021-12-06&end_date=2021-12-09&detailed=false&api_key=Na1sKwJGK1HVeOF4Yx8aLNp4u8ygT5GSSMF26HQ2",
    "self": "http://www.neowsapp.com/rest/v1/feed?start_date=2021-12-09&end_date=2021-12-12&detailed=false&api_key=Na1sKwJGK1HVeOF4Yx8aLNp4u8ygT5GSSMF26HQ2"
},
"element_count": 76,
"near_earth_objects": {
    "2021-12-12": [
        {
            "links": {
                "self": "http://www.neowsapp.com/rest/v1/neo/2004341?api_key=Na1sKwJGK1HVeOF4Yx8aLNp4u8ygT5GSSMF26HQ2"
            },
            "id": "2004341",
            "neo_reference_id": "2004341",
            "name": "4341 Poseidon (1987 KF)",
            "nasa_jpl_url": "http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2004341",
            "absolute_magnitude_h": 16.05,
            "estimated_diameter": {
                "kilometers": {
                    "estimated_diameter_min": 1.6389095149,
                    "estimated_diameter_max": 3.6647130844
                },
                "meters": {
                    "estimated_diameter_min": 1638.9095149478,
                    "estimated_diameter_max": 3664.7130843945
                },
                "miles": {
                    "estimated_diameter_min": 1.0183708442,
                    "estimated_diameter_max": 2.277146434
                },
                "feet": {
                    "estimated_diameter_min": 5376.9998930214,
                    "estimated_diameter_max": 12023.337275805
                }
            },
            "is_potentially_hazardous_asteroid": false,
            "close_approach_data": [
                {
                    "close_approach_date": "2021-12-12",
                    "close_approach_date_full": "2021-Dec-12 13:35",
                    "epoch_date_close_approach": 1639316100000,
                    "relative_velocity": {
                        "kilometers_per_second": "17.8282207618",
                        "kilometers_per_hour": "64181.5947426121",
                        "miles_per_hour": "39879.9470221525"
                    },
                    "miss_distance": {
                        "astronomical": "0.3316696597",
                        "lunar": "129.0194976233",
                        "kilometers": "49617074.634744839",
                        "miles": "30830620.5431592182"
                    },
                    "orbiting_body": "Earth"
                }
            ],
            "is_sentry_object": false
        },

making this model

public class Near_Earth_Objects
{
    [JsonProperty("id")]
    public int Id { get; set; }
    [JsonProperty("name")]
    public string Nombre { get; set; }
    
    [JsonProperty("estimated_diameter:kilometers:estimated_diameter_min")]
    public double DiametroMin { get; set; }
    
    [JsonProperty("estimated_diameter:kilometers:estimated_diameter_max")]
    public double DiametroMax { get; set; }
    
    [JsonProperty("close_approach_data:relative_velocity:kilometers_per_hour")]
    public double Velocidad { get; set; }
    
    [JsonProperty("close_approach_data: close_approach_date")]
    public DateTime Fecha { get; set; }
    
    [JsonProperty("close_approach_date: orbiting_body")]
    public string Planeta { get; set; }
}

my deserialization code is this

public async Task<IEnumerable<Near_Earth_Objects>> GetAllNeos()
{
    var json = await _httpClient.GetStringAsync($"feed?start_date=2021-11-07&end_date=2021-11-10&api_key=Na1sKwJGK1HVeOF4Yx8aLNp4u8ygT5GSSMF26HQ2");
    return JsonConvert.DeserializeObject<IEnumerable<Near_Earth_Objects>>(json);
}

to see what JSON response try this on POSTMAN:

我希望這個答案對你有所幫助。祝你好運。

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標籤：c# json .net serialization json.net

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