在处理大型的XML文档的时候,在服务器端直接使用XML DOM的时候速度是比较慢的,当我第一次接触到SAX的时候,我意识到我们应该在服务器端将DOM和SAX结合起来以提高我们程序的效率。我们在ASP中最常使用的就是使用COM来完成这个工作(也许你有更好的方法,下面只是包含了最基本的代码而已 )。
首先我们创建一个DLL来封装SAX的功能好了。
测试环境:Win2k Prof.+MSXML3.0 sp1+VB6
要使用SAX我们必须引用(Reference)Microsoft XML 3.0(我的机器安装的是MSXML3.0 sp1)
工程名:SAXTesting
类名:clsSAXTest
方法:Public Function MyXMLParser(XML文件物理路径) as DOMDocument
代码:
Option Explicit
Public Function MyXMLParser(ByVal strXMLFilePath As Variant) As DOMDocument
Dim reader As New SAXXMLReader
Dim contentHandler As New ContentHandlerImpl
Dim errorHandler As New ErrorHandlerImpl
Set reader.contentHandler = contentHandler
Set reader.errorHandler = errorHandler
On Error GoTo ErrorHandle
Dim XMLFile As String
XMLFile = strXMLFilePath
reader.parseURL (XMLFile)
Dim xmlDoc As MSXML2.DOMDocument
Set xmlDoc = CreateObject("MSXML2.DOMDocument")
xmlDoc.loadXML strXML
Set MyXMLParser = xmlDoc
Set xmlDoc = Nothing
Exit Function
ErrorHandle:
Err.Raise 9999, "My XML Parser", Err.Number & " : " & Err.Description
End Function
类名:modPublic
代码:
Option Explicit
Global strXML As String
类名:ContentHandlerImpl
代码:
Option Explicit
Implements IVBSAXContentHandler
Private Sub IVBSAXContentHandler_startElement(strNamespaceURI As String, strLocalName As String,
strQName As String, ByVal attributes As MSXML2.IVBSAXAttributes)
Dim i As Integer
intLocker = intLocker + 1
If intLocker > 1 Then
End If
strXML = strXML & "<" & strLocalName
For i = 0 To (attributes.length - 1)
strXML = strXML & " " & attributes.getLocalName(i) & "=""" & attributes.getValue(i) &
""""
Next
strXML = strXML & ">"
If strLocalName = "qu" Then
Err.Raise vbObjectError + 1, "ContentHandler.startElement", "Found element <qu>"
End If
End Sub