Web在VBA中仅抓取网页的特定部分

Question

我正在重新审视网络抓取，以尝试开发一种可以从数据库中提取数据的工具。

我在这里使用的物质档案位于：https://echa.europa.eu/registration-dossier/-/registered-dossier/16016/7/1。

这里列出了可以在此档案中找到的各种毒理学信息，但我只对此处称为 DNEL 的出发点值 (POD) 感兴趣：

基本上复制一个答案给我提供了一段时间，我有以下代码来提取第一个 POD。

Public Sub GetContents()
    

'Start ECHA Search via XML HTTP Request

Dim XMLReq As New MSXML2.XMLHTTP60
Dim HTMLDoc As New MSHTML.HTMLDocument

XMLReq.Open "Get", "https://echa.europa.eu/registration-dossier/-/registered-dossier/16016/7/1", False
XMLReq.send
 
If XMLReq.Status <> 200 Then
        
    MsgBox "Problem" & vbNewLine & XMLReq.Status & " - " & XMLReq.statusText
    Exit Sub

    End If
 
HTMLDoc.body.innerHTML = XMLReq.responseText


'Retrieve Data

'POD Population and Route
Set Info = HTMLDoc.getElementById("sWorkersHazardViaInhalationRoute")

Debug.Print Info.innerText

'POD Type
Set Info = HTMLDoc.getElementsByClassName("HorDL")(0)
Set data = Info.getElementsByTagName("dd")(0)
Debug.Print data.innerText

'POD Value
Set data = Info.getElementsByTagName("dd")(1)
Debug.Print data.innerText

End Sub

这可以为第一个管理途径拉取 POD：WorkersHazardViaDermalRoute

Workers - Hazard via inhalation route
DNEL (Derived No Effect Level)
238 mg/m³

这很好，但我真的希望能够对其进行调整，以提取 DNEL 及其对每种给药途径的价值。此处以蓝色突出显示：

因此，对于这个示例，整个所需的输出将跨越 3 列（虽然只是想提取数据，但它现在在 3 列中并不重要）：

Workers - Hazard via inhalation route, DNEL (Derived No Effect Level), 238 mg/m³
Workers - Hazard via dermal route, DNEL (Derived No Effect Level), 84 mg/kg bw/day
General Population - Hazard via inhalation route, DNEL (Derived No Effect Level), 70 mg/m³
General Population - Hazard via dermal route, DNEL (Derived No Effect Level), 51 mg/kg bw/day
General Population - Hazard via oral route, DNEL (Derived No Effect Level), 24 mg/kg bw/day

我遇到的问题是我正在使用类元素“HorDL”来获取此信息，但不幸的是，该类不仅限于每条路线以蓝色突出显示的部分。所以 ("HorDL")(0) 可以找到，但是 ("HorDL")(1) 会立即在下面提取相同路线的信息。

出于这个原因，我怀疑使用这个类元素来提取信息并不是最好的方法，但是我想不出任何其他方法来做到这一点。

我已经有办法提取相关的档案，所以如果这可行，它将成为一个只提取相关信息的 Neat 工具。我考虑过提取所有信息，然后在 excel 中应用过滤器，但我认为这不是一个特别优雅的解决方案。

非常感谢任何回复。

Answer 1

这假设您只想要标题中带有关键字Workers 和General Population 的DNEL，其中排除带有Hazard for the eyes 的DNEL

注意：您应该声明所有变量，在模块顶部插入 Option Explicit 以帮助您执行它。

Option Explicit

Public Sub GetContents()
    Const DNELTitle As Long = 1
    Const DNELAssessment As Long = 2
    Const DNELValue As Long = 3
    
    Const resultFirstCell As String = "A1" 'Change the first cell address to insert the result accordingly
    
    Dim ws As Worksheet
    Set ws = ThisWorkbook.Worksheets("Sheet1") 'Change worksheet name accordingly
    
    'Start ECHA Search via XML HTTP Request
    Dim XMLReq As New MSXML2.XMLHTTP60
    Dim HTMLDoc As New MSHTML.HTMLDocument
    
    XMLReq.Open "Get", "https://echa.europa.eu/registration-dossier/-/registered-dossier/16016/7/1", False
    XMLReq.send
     
    If XMLReq.Status = 200 Then
        HTMLDoc.body.innerHTML = XMLReq.responseText
        
        '==== Loop through each anchors and get the relevant ID for interested DNEL
        Dim anchors As Object
        Set anchors = HTMLDoc.getElementById("SectionAnchors")
        Set anchors = anchors.getElementsByTagName("a")
        
        Dim anchorsColl As Collection
        Set anchorsColl = New Collection
        
        Dim i As Long
        For i = 0 To anchors.Length - 1
            Dim anchorText As String
            anchorText = anchors(i).innerText
            
            If InStr(anchorText, "Workers - ") <> 0 Or _
                InStr(anchorText, "General Population - ") <> 0 Then
                
                If InStr(anchorText, "Additional Information") = 0 And _
                    InStr(anchorText, "Hazard for the eyes") = 0 Then
                    
                    anchorsColl.Add Replace(anchors(i).href, "about:blank#", vbNullString)
                End If
            End If
        Next i
        '====
        
        If anchorsColl.Count <> 0 Then
            Dim outputArr() As String
            ReDim outputArr(1 To anchorsColl.Count, 1 To 3) As String
            
            For i = 1 To anchorsColl.Count
                Dim anchorEle As Object
                                
                Set anchorEle = HTMLDoc.getElementById(anchorsColl(i))
                outputArr(i, DNELTitle) = anchorEle.innerText
                
                'Loop through the anchor's sibling until it finds the DL tag to extract the values
                Do While anchorEle.nodeName <> "DL"
                    Set anchorEle = anchorEle.NextSibling
                Loop
                
                'Assumes that the assessment conclusion is in the first DD tag
                'Assumes that the value is in the second DD tag
                outputArr(i, DNELAssessment) = anchorEle.getElementsByTagName("dd")(0).innerText
                outputArr(i, DNELValue) = anchorEle.getElementsByTagName("dd")(1).innerText
            Next i
            
            'Write the extraction result to the worksheet starting from A1
            ws.Range(resultFirstCell).Resize(UBound(outputArr, 1), 3).Value = outputArr
        Else
            Debug.Print "No DNEL found."
        End If
        
        Set ws = Nothing
        Set HTMLDoc = Nothing
    Else
        MsgBox "Problem" & vbNewLine & XMLReq.Status & " - " & XMLReq.statusText
    End If
    
    Set XMLReq = Nothing
End Sub

Answer 2

到目前为止我自己的答案。

接下来，我将循环遍历一个值列表，以返回每个值的 DNEL。还需要包含某种错误处理。

Sub GetData()
    

'Start ECHA Search via XML HTTP Request

Dim XMLReq As New MSXML2.XMLHTTP60
Dim HTMLDoc As New MSHTML.HTMLDocument

XMLReq.Open "Get", "https://echa.europa.eu/registration-dossier/-/registered-dossier/16016/7/1", False
XMLReq.send
 
If XMLReq.Status <> 200 Then
        
    MsgBox "Problem" & vbNewLine & XMLReq.Status & " - " & XMLReq.statusText
    Exit Sub

    End If
 
HTMLDoc.body.innerHTML = XMLReq.responseText


'Retrieve Data for General population

'Defines class element for each route
Dim Route(1 To 3) As String

Route(1) = "sGeneralPopulationHazardViaInhalationRoute"
Route(2) = "sGeneralPopulationHazardViaDermalRoute"
Route(3) = "sGeneralPopulationHazardViaOralRoute"

'Loops through each element

r = 4
c = 6

Dim i As Long

For i = 1 To UBound(Route, 1)


Set Info = HTMLDoc.getElementById(Route(i))
Debug.Print Info.innerText

Set Info = HTMLDoc.getElementById(Route(i)).NextSibling.NextSibling.NextSibling
Set Data = Info.getElementsByTagName("dd")(0)
Debug.Print Data.innerText

Set Data = Info.getElementsByTagName("dd")(1)
Debug.Print Data.innerText


Cells(r, c) = Data.innerText

c = c + 1

Next i

r = r + 1


End Sub