VB.Net_Having 从 JSON 读取令牌时出现问题

Question

读取天气数据的程序

这是回复(json):

coord   
lon -0.1257
lat 51.5085
weather 
0   
id  802
main    "Clouds"
description "scattered clouds"
icon    "03d"
base    "stations"
main    
temp    22.43
feels_like  22.4
temp_min    19.82
temp_max    24.21
pressure    1021
humidity    64
visibility  10000
wind    
speed   4.12
deg 270
clouds  
all 40
dt  1625834363
sys 
type    2
id  2006068
country "GB"
sunrise 1625802859
sunset  1625861805
timezone    3600
id  2643743
name    "London"
cod 200

这是我用来 select 来自 json 的代码：

Imports System.Net
Imports System.IO
Imports Newtonsoft.Json.Linq
    Public deg As String = Chr(176)
    Public iconid As String = ""
    Public locationstr As String
    Public ApiKey As String = "MYAPIKEY"
#Region "Conditions"
    Public windspeedMPS As String = ""
    Public humidity As String = ""
    Public description As String
    Public cloudiness As String = ""
    Public temp As String = ""
    Public City As String = ""
#End Region

    Public Sub getweather(ByVal key As String)
        Dim req As HttpWebRequest = DirectCast(WebRequest.Create("http://api.openweathermap.org/data/2.5/weather?q=" & locationstr & "&appid=" & ApiKey & "&lang=en&units=metric"), HttpWebRequest)
        Dim res As HttpWebResponse = DirectCast(req.GetResponse, HttpWebResponse)
        Dim reader As New StreamReader(res.GetResponseStream)
        Dim serverresponse As String = reader.ReadToEnd
        Dim json As String = serverresponse
        Dim obj As JObject = JObject.Parse(json)
        Try
            windspeddMPS = obj.SelectToken("wind").SelectToken("speed")
            humidity = obj.SelectToken("main").SelectToken("humidity")
            description = obj.SelectToken("weather").SelectToken("description")
            cloudiness = obj.SelectToken("clouds").SelectToken("all")
            temp = obj.SelectToken("main").SelectToken("temp")
            City = obj.SelectToken("name")
            iconid = obj.SelectToken("weather").SelectToken("icon")
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

我可以 select 除了“描述”（组内的天气状况）和“图标”（天气状况图标 ID）令牌之外的所有令牌。

Answer 1

作为参考，这里是您正在使用的 API 网络文档：https://openweathermap.org/current

Visual Studio 有一个很酷的功能，称为将 JSON 粘贴为类，可以在编辑 > 选择性粘贴 > 将 JSON 粘贴为类下找到。如果你这样做，那么你会得到如下所示的东西：


Public Class Rootobject
    Public Property coord As Coord
    Public Property weather() As Weather
    Public Property base As String
    Public Property main As Main
    Public Property visibility As Integer
    Public Property wind As Wind
    Public Property clouds As Clouds
    Public Property dt As Integer
    Public Property sys As Sys
    Public Property timezone As Integer
    Public Property id As Integer
    Public Property name As String
    Public Property cod As Integer
End Class

Public Class Coord
    Public Property lon As Single
    Public Property lat As Single
End Class

Public Class Main
    Public Property temp As Single
    Public Property feels_like As Single
    Public Property temp_min As Single
    Public Property temp_max As Single
    Public Property pressure As Integer
    Public Property humidity As Integer
End Class

Public Class Wind
    Public Property speed As Single
    Public Property deg As Integer
End Class

Public Class Clouds
    Public Property all As Integer
End Class

Public Class Sys
    Public Property type As Integer
    Public Property id As Integer
    Public Property message As Single
    Public Property country As String
    Public Property sunrise As Integer
    Public Property sunset As Integer
End Class

Public Class Weather
    Public Property id As Integer
    Public Property main As String
    Public Property description As String
    Public Property icon As String
End Class

从这里，您可以反序列化 JSON 对 Rootobject class 的响应，这反过来您可以访问强类型对象以获取您的值：

' ... HTTP request to get JSON
Dim jsonObject = JsonConvert.DeserializeObject(Of Rootobject)(json)
Console.WriteLine(jsonObject.clouds.all)

VB.Net_Having 从 JSON 读取令牌时出现问题

VB.Net_Having Problem with reading a token from JSON

vb.net

api

json