从Web服务器下载文件

问题描述

我从URL得到以下响应.我该如何编码将两个文件下载到名称为id的硬盘中.

I have the following response from a URL. How do I code to download the two files to my hard drive with the name = id.

HTTP/1.1 200 OK
Content-Type: application/json

{
  "files": [
    {
      "format": "fillz-order-tab",
      "checksum": "6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b",
      "acknowledged": false,
      "uri": "https://file-api.fillz.com/v1/orders/created/20140611T003336Z-8b975127",
      "date_created": "20140611T003336Z",
      "id": "20140611T003336Z-8b975127"
    },
    {
      "format": "fillz-order-tab",
      "checksum": "d4735e3a265e16eee03f59718b9b5d03019c07d8b6c51f90da3a666eec13ab35",
      "acknowledged": false,
      "uri": "https://file-api.fillz.com/v1/orders/created/20140611T013545Z-3e2f2083",
      "date_created": "20140611T013545Z",
      "id": "20140611T013545Z-3e2f2083"
    }
  ]
}

我调用URL的代码如下:

My code that calls the URL is the following:

Using response As HttpWebResponse = TryCast(request.GetResponse(), HttpWebResponse)
                    Dim reader As New StreamReader(response.GetResponseStream())
                    result = reader.ReadToEnd()

我在Visual Basic 2008中使用json.net.

I am using json.net with visual basic 2008.

这些是我的课程

Public Class file
    Public format As String
    Public checksum As String
    Public acknowledged As String
    Public uri As String
    Public date_created As String
    Public id As String
End Class


Public Class RootObject
    Public Property files() As List(Of file)
        Get

        End Get
        Set(ByVal value As List(Of file))

        End Set

    End Property
End Class

这是我反序列化json结果的代码

This is my code to deserializare json results

Dim res As RootObject = JsonConvert.DeserializeObject(Of FillzAPI.FileAPI.RootObject)(result)

我想从网址响应中读取每个ID

I want to read each id from the url response

For Each Data As FileAPI.RootObject In res

Next

下一个错误:

表达式的类型为'FillzAPI.FileAPI.RootObject'，这不是集合类型.

Expression is of type 'FillzAPI.FileAPI.RootObject', which is not a collection type.

如何解决此错误?

推荐答案

一些可以为您工作的代码:

A few points which will give you working code:

• 有一种下载JSON数据的简便方法.
• 你不小心将RootObject.files声明为列表数组，并将其Get和Set方法为空.
• File是类的不幸名称，因为它与System.IO.File冲突.
• 最好有(我命名为)FileData中的内容作为属性.你可以采取自动声明的属性的优势，而不必键入Get/Set方法.

• There is an easier way to download the JSON data.
• You've accidentallydeclared RootObject.files as an array of lists, and its Get andSet methods are empty.
• File is an unfortunate name for a class asit conflicts with System.IO.File.
• It would be better to have thethings in (what I named) FileData as properties. You can takeadvantage of auto-declared properties and not have to type theGet/Set methods.

将所有这些放在一起，我到达了

Putting all those together, I arrived at

 Option Infer On

Imports System.IO
Imports System.Net
Imports Newtonsoft.Json

Module Module1

    Public Class FileData
        Public Property format As String
        Public Property checksum As String
        Public Property acknowledged As String
        Public Property uri As String
        Public Property date_created As String
        Public Property id As String
    End Class

    Public Class RootObject
        Public Property Files As List(Of FileData)
    End Class

    Sub Main()
        ' I set this up on a local web server. Adjust as required.
        Dim src = "http://127.0.0.1/JsonSample.txt"

        ' An easy way to get a string from a web server...
        Dim wc As New WebClient
        'TODO: Try..Catch any error that wc.DownloadString throws.
        Dim jsonData = wc.DownloadString(src)

        'TODO: Try..Catch any error that JsonConvert.DeserializeObject throws.
        Dim y = JsonConvert.DeserializeObject(Of RootObject)(jsonData)

        ' Somewhere to save the downloaded files...
        Dim dest = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory), "My JSON test")
        If Not Directory.Exists(dest) Then
            Directory.CreateDirectory(dest)
        End If

        For Each x In y.Files
            Console.WriteLine(x.uri)
            'TODO: Try..Catch any error that wc.DownloadFile throws. Also perhaps use async methods.
            wc.DownloadFile(x.uri, Path.Combine(dest, x.id))
        Next

        Console.ReadLine()

    End Sub

End Module

哪个输出

并保存文件.

这篇关于从Web服务器下载文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！