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）。 

废话少说，还是直接进入实际的代码部分了（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 

Private Sub IVBSAXContentHandler_endElement(strNamespaceURI As String, strLocalName As String, 

strQName As String) 
     
    strXML = strXML & "</" & strLocalName & ">" 
     
End Sub 

Private Sub IVBSAXContentHandler_characters(text As String) 
    text = Replace(text, vbLf, vbCrLf) 
    strXML = strXML & text 
     
End Sub 

Private Property Set IVBSAXContentHandler_documentLocator(ByVal RHS As MSXML2.IVBSAXLocator) 

End Property 

Private Sub IVBSAXContentHandler_endDocument() 

End Sub 

Private Sub IVBSAXContentHandler_endPrefixMapping(strPrefix As String) 

End Sub 

Private Sub IVBSAXContentHandler_ignorableWhitespace(strChars As String) 

End Sub 

Private Sub IVBSAXContentHandler_processingInstruction(target As String, data As String)
     
    strXML = strXML & "<?" & target & " " & data & ">" 

End Sub 

Private Sub IVBSAXContentHandler_skippedEntity(strName As String) 

End Sub 

Private Sub IVBSAXContentHandler_startDocument() 

End Sub 

Private Sub IVBSAXContentHandler_startPrefixMapping(strPrefix As String, strURI As String) 

End Sub 


类名：ErrorHandlerImpl 
代码： 
Option Explicit 

Implements IVBSAXErrorHandler 


Private Sub IVBSAXErrorHandler_fatalError(ByVal lctr As IVBSAXLocator, msg As String, ByVal 

errCode As Long) 
         
        strXML = strXML & "*** error *** " & msg 
     
End Sub 

Private Sub IVBSAXErrorHandler_error(ByVal lctr As IVBSAXLocator, msg As String, ByVal errCode As 

Long) 
     
End Sub 

Private Sub IVBSAXErrorHandler_ignorableWarning(ByVal oLocator As MSXML2.IVBSAXLocator, 

strErrorMessage As String, ByVal nErrorCode As Long) 

End Sub 


OK，让我们编译这个DLL，应该是没什么问题了。让我们在ASP中看看运行的结果怎么样： 
XML文件： 
<?xml version="1.0"?> 
<root foo="bar.com"> 
<PARTS> 
   <PART foo="bar.com"  foo2="bar.com"> 
<PARTNO>12345</PARTNO> 
<DESCRIPTION>VIP - Very Important Part</DESCRIPTION> 
   </PART> 
   <PART> 
<PARTNO>5678</PARTNO> 
<DESCRIPTION>LIP - Less Important Part</DESCRIPTION> 
   </PART> 
</PARTS> 
</root> 

ASP文件： 
<% 
Set a = CreateObject("SAXTesting.clsSAXTest") 
Set xmlDoc = a.MyXMLParser("D:\test.xml") 
Response.contenttype="text/xml" 
response.write xmlDoc.xml 
set xmlDoc=nothing 
set a=nothing 
%>