将sax加入我们的asp应用中

    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 !amp; " : " !amp; 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 !amp; "<" !amp; strlocalname



for i = 0 to (attributes.length - 1)

strxml = strxml !amp; " " !amp; attributes.getlocalname(i) !amp; "=""" !amp; attributes.get＆#118alue(i) !amp;



""""

next



strxml = strxml !amp; ">"



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 !amp; "</" !amp; strlocalname !amp; ">"



end sub



private sub ivbsaxcontenthandler_characters(text as string)

text = replace(text, vblf, vbcrlf)

strxml = strxml !amp; 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 !amp; "<@" !amp; target !amp; " " !amp; data !amp; ">"



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 !amp; "*** error *** " !amp; 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

%>