Question

我需要将此URL下载到json，以便将其转换为对象。

不过，当我运行以下代码时，字符串返回为“”。

URL：https://data.ny.gov/resource/d6yy-54nr.json

我在做什么错了？

注意：代码在VB.net中，对象在C＃中（没关系）

    Protected Sub btnProcess_Click(sender As Object, e As EventArgs)
        Try
            Dim result = DownloadAndSerializedJsonFromUrl(Of a27baseball.Common.Objects.Oreo.DownloadJsonPowerball)("https://data.ny.gov/resource/5xaw-6ayf.json")
        Catch ex As Exception
            Response.Write(ex.ToString())
        End Try
    End Sub

    Private Function DownloadAndSerializedJsonFromUrl(Of T As New)(ByVal url As String) As T
        Using w = New WebClient()
            Dim json_data = String.Empty

            Try
                json_data = w.DownloadString(url)
            Catch __unusedException1__ As Exception
                Response.Write(__unusedException1__.ToString())
            End Try

            Return If(Not String.IsNullOrEmpty(json_data), JsonConvert.DeserializeObject(Of T)(json_data), New T())
        End Using
    End Function

namespace a27baseball.Common.Objects.Oreo
{
    public class DownloadJsonPowerball
    {
        public string draw_date { get; set; }

        public string winning_numbers { get; set; }

        public string multiplier { get; set; }
    }
}

Answer 1

您应该反序列化为List<a27baseball.Common.Objects.Oreo.DownloadJsonPowerball>类型，而不是a27baseball.Common.Objects.Oreo.DownloadJsonPowerball类型。由于json文件的内容包含您对象类型的数组。

 Dim result = DownloadAndSerializedJsonFromUrl(Of List(Of a27baseball.Common.Objects.Oreo.DownloadJsonPowerball))("https://data.ny.gov/resource/5xaw-6ayf.json")

Answer 2

 public static void Json()
            {
                string url = "https://data.ny.gov/resource/d6yy-54nr.json";
                WebRequest request = WebRequest.Create(url);
                WebResponse reply;
                reply = request.GetResponse();
                StreamReader returninfo = new StreamReader(reply.GetResponseStream());
                string getinfo = returninfo.ReadToEnd();
                List<Draw> Info = Newtonsoft.Json.JsonConvert.DeserializeObject<List<Draw>>(getinfo);
                foreach (var info in Info)
                {



                }
 public class Draw
    {
        public DateTime draw_time { get; set; }
        public string winning_numbers { get; set; }
        public string multiplier { get; set; }
    }

我这样尝试过，也许可以帮上忙。

Answer 3

100％正确答案：

我错过了这一行代码：

   ServicePointManager.SecurityProtocol = CType(3072, SecurityProtocolType)

最终代码：

   Private Function DownloadAndSerializedJsonFromUrl(Of T As New)(ByVal url As String) As T
        Using w = New WebClient()
            Dim json_data = String.Empty

            Try
                ServicePointManager.SecurityProtocol = CType(3072, SecurityProtocolType)
                json_data = w.DownloadString(url)
            Catch __unusedException1__ As Exception
                Response.Write(__unusedException1__.ToString())
            End Try

            Return If(Not String.IsNullOrEmpty(json_data), JsonConvert.DeserializeObject(Of T)(json_data), New T())
        End Using
    End Function

字符串中不存在JSON数据，我可以使用JsonConver DeserializeObject方法将其转换！

谢谢大家！

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https://stackoverflow.com/users/login?ssrc=head&returnurl=https%3a%2f%2fstackoverflow.com%2fquestions%2f22627977%2fthe-underlying-connection-was-closed-an-unexpected-error-occurred-on-a-send

将.json文件从URL下载到对象

3 个答案: