实践xml缓存技术构建高性能web站点

打造一个高性能稳定的web站点一直是站长和程序员的梦想，本文用作者的一次亲身经历的来说说如何利用xml缓存技术实现站点的高性能。我是从今年开始做138手机主题网的，采用SQL2000做为数据库，开发语言用的是Asp，查询的时候都是动态查询，直接用like %的方式，那个时候反正一天的访问量小，同时在线的时候也就几十个人而已，所以服务器也就能胜任要求，随着访问量慢慢增加，当同时在线达到几百人时，此时服务器开始不堪重负，CPU常常达到100%不降，网页打开速度也超级慢，一个查询页面需要几秒钟甚至更长，于是我开始考虑优化程序和数据库，数据库建立索引，不是很理想，因为用的是like '% 这种方式，于是我想到了缓存，而xml本身的特点决定了他非常适合做数据库的缓存，好东西不敢独享，特发布出来，以便同行交流，共同进步。
实现的思路是这样的：程序读取信息时，先判断是否缓存了xml数据，如果有，则直接从xml中读取信息，否则从数据库中读取，并将此次结果生成xml文件，以便以后调用，加快速度，同时判断xml缓存文件是否过期，如果过期则需要重新生成xml。下面是具体的代码。
xmlcachecls.asp
<%
Rem xml数据缓存类
'--------------------------------------------------
'转载的时候请保留版权信息
'作者:walkman
'网址:手机主题 http://www.shouji138.com
'版本:ver1.0
'欢迎各位交流进步
'--------------------------------------------------
Class XmlCacheCls
 Rem 私有变量定义
 Private m_CacheTime  '缓存时间，单位秒
 Private m_PageSize  '每页大小
 Private m_CachePageNum 'xml缓存页大小
 Private m_XmlFile  'xml路径，用绝对地址,不需要加扩展名
 Private m_Sql   'SQL语句
 Private m_TableName  '表名或者视图名
 Private m_Columns  '列名 用,隔开
 Private m_CurPage  '当前页
 Private m_CacheType  '缓存类型：1,列表 2,详情
 Private m_DataConn  '数据源,必须已经打开
 Private m_QueryType  '查询类型：1,直接用sql 2,用存储过程
 Private m_SQLArr  '返回的数据数组
 Private m_RecordCount
 
 
 Rem 公共属性
 '缓存时间
 Public Property Let  CacheTime(v)
  m_CacheTime = v
 End Property
 Public Property Get  CacheTime
  CacheTime = m_CacheTime
 End Property
 
 '每页大小
 Public Property Let  PageSize(v)
  m_PageSize = v
 End Property
 Public Property Get  PageSize
  PageSize = m_PageSize
 End Property
 
 'xml缓存页大小
 Public Property Let  CachePageNum(v)
  m_CachePageNum = v
 End Property
 Public Property Get  CachePageNum
  CachePageNum = m_CachePageNum
 End Property
 
 'xml路径，用绝对地址
 Public Property Let  XmlFile(v)
  m_XmlFile = v
 End Property
 Public Property Get  XmlFile
  XmlFile = m_XmlFile
 End Property

 'xml路径，用绝对地址
 'http://www.knowsky.com/article.asp?typeid=2
 Public Property Let  Sql(v)
  m_Sql = v
 End Property
 Public Property Get  Sql
  Sql = m_Sql
 End Property

 '表名或者视图名
 Public Property Let  TableName(v)
  m_TableName = v
 End Property
 Public Property Get  TableName
  TableName = m_TableName
 End Property
 
 '列名 用,隔开
 Public Property Let  Columns(v)
  m_Columns = v
 End Property
 Public Property Get  Columns
  Columns = m_Columns
 End Property
 
 '当前页
 Public Property Let  CurPage(v)
  m_CurPage = v
 End Property
 Public Property Get  CurPage
  CurPage = m_CurPage
 End Property

 '缓存类型：1,列表 2,详情
 Public Property Let  CacheType(v)
  m_CacheType = v
 End Property
 Public Property Get  CacheType
  CacheType = m_CacheType
 End Property
 
 '缓存类型：1,列表 2,详情
 Public Property Set  Conn(v)
  Set m_DataConn = v
 End Property
 Public Property Get  Conn
  Conn = m_DataConn
 End Property

 '返回记录总数
 Public Property Get  RecordCount
  RecordCount = m_RecordCount
 End Property
 '返回记录数组
 'http://www.devdao.com/
 Public Property Get  SQLArr
  SQLArr = m_SQLArr
 End Property

 Rem 公共方法 读取数据
 Public Function ReadData
  If m_CacheType = 1 Then
   ReadListAndSearchData
  Else
   ReadContentData
  End If
 End Function
 
 Rem 读取详情信息
 Private Function ReadContentData
  Dim xmlfile
  xmlfile = m_XmlFile
  If FSOExistsFile(xmlfile) Then '存在xml缓存，直接从xml中读取
   ReadContentDataFromXml xmlfile
  Else
   ReadContentDataFromDB
  End If
 End Function
 
 Rem 从xml文件读取详情信息
 Private Function ReadContentDataFromXml(xmlfile)
  Dim SQLARR()
  Dim XmlDoc
  Set XmlDoc = Server.CreateObject("msxml2.FreeThreadedDOMDocument.3.0")
  XmlDoc.Load xmlfile
  Dim itemslength,itemsi
  itemslength = XmlDoc.documentElement.childNodes.length
  For itemsi=0 To itemslength-1
   ReDim Preserve SQLARR(itemslength-1,0)
   SQLARR(itemsi,0) = XmlDoc.documentElement.childNodes(itemsi).text
  Next
  Set XmlDoc = Nothing
  m_SQLArr = SQLArr
 End Function
 
 Rem 从Db中读取详情信息
 Private Function ReadContentDataFromDB()
  Dim rs
  Dim SQLARR
  Set rs = m_DataConn.execute(m_sql)
  IF Not Rs.eof Then
   SQLArr=Rs.GetRows(1)
   rs.close
   Set rs = Nothing
  Else
   rs.close
   Set rs = Nothing
   Exit Function
  End If
  m_SQLArr = SQLArr
 End Function

 Rem 读取列表数据
 Private Function ReadListAndSearchData
  Dim sPagesize,TotalPage,CurPage,TotalRec
  sPagesize = m_PageSize * m_CachePageNum
  m_CurPage = CLng(m_CurPage)
 
  If m_CurPage Mod m_CachePageNum = 0 Then
   CurPage = m_CurPage/m_CachePageNum
  Else
   CurPage = int(clng(m_CurPage)/m_CachePageNum)+1
  End If
  Dim xmlfile
  xmlfile = getXmlFileName(CurPage)
  If FSOExistsFile(xmlfile) Then '存在xml缓存，直接从xml中读取
   ReadListAndSearchDataFromXml xmlfile
  Else
   ReadListAndSearchDataFromDB
  End If
 End Function
 Rem 从xml中读列表数据
 Private Function ReadListAndSearchDataFromXml(xmlfile)
  Dim SQLARR()
  Dim XmlDoc
  Set XmlDoc = Server.CreateObject("msxml2.FreeThreadedDOMDocument.3.0")
  XmlDoc.Load xmlfile
  Dim totalrecont
  totalrecont = XmlDoc.documentElement.selectSingleNode("totalrec").text
  m_RecordCount = totalrecont
  Dim TotalRec
  TotalRec = m_RecordCount
  If totalrecont = 0 Then
   Set XmlDoc = Nothing
   m_SQLArr = SQLARR
   Exit Function
  End If
  Dim TotalPage,curpage
  curpage = m_CurPage
  If m_CurPage Mod m_CachePageNum = 0 Then
   CurPage = m_CurPage/m_CachePageNum
  Else
   CurPage = int(clng(m_CurPage)/m_CachePageNum)+1
  End If
  If TotalRec Mod m_CachePageNum =0 Then
   TotalPage = totalrecont/m_CachePageNum
  Else
   TotalPage = int(clng(totalrecont)/m_CachePageNum)+1
  End If
 
  If curpage>TotalPage Then curpage=TotalPage
  Dim starti
  Dim startn
  startn = m_curpage - (curpage-1) * m_CachePageNum
  Rem 计算开始位置
  starti = (startn-1) * m_pagesize
  Dim items,item
  Set items = XmlDoc.documentElement.SelectNodes("item")
  Dim i
  Dim num
  Dim length
  length = items.length
  num = 0
  For i = starti To m_PageSize + starti -1
   If i >=length Then Exit For
   Set item = items(i)
   Dim attrlength
   attrlength = item.attributes.length
   ReDim Preserve SQLARR(attrlength,num)
   Dim Attribute
   Dim Attributei
   Attributei = 0
   For Attributei = 0 To attrlength-1
    SQLArr(Attributei,num) = item.attributes(Attributei).Nodevalue
   Next  
   num = num + 1
  Next
  Set XmlDoc = Nothing
  m_SQLArr = SQLArr
 End Function
 
 Rem 从DB中读列表数据
 Private Function ReadListAndSearchDataFromDB
  Dim rs,TotalRec,CurPage
  CurPage = m_CurPage
  Set Rs = Server.CreateObject("Adodb.Recordset")
  Rs.open m_sql,m_DataConn,1
  TotalRec = rs.recordcount
  m_RecordCount = TotalRec
  rs.pagesize = m_PageSize
  If  CurPage>rs.PageCount Then  CurPage = rs.PageCount
  If Not rs.eof Then rs.absolutePage=m_CurPage
  Dim SQLARR()
  Dim k
  k = 0
  While Not rs.eof and k<m_PageSize
   Dim fieldlegth
   fieldlegth = rs.Fields.count
   ReDim Preserve SQLARR(fieldlegth,k)
  
   Dim fieldi
   For fieldi = 0 To fieldlegth-1
    SQLArr(fieldi,k) = rs.Fields(fieldi).value
   Next
   rs.movenext
   k=k+1
  Wend
  rs.close
  Set rs = Nothing
  m_SQLArr = SQLArr
 End Function

 Rem 获取xml文件名称
 Private Function getXmlFileName(num)
  Dim tmpstr
  tmpstr = LCase(m_XmlFile)
  If Right(tmpstr,4) = ".xml" Then
   tmpstr = Left(tmpstr,Len(tmpstr)-Len(".xml"))
  End If
  tmpstr = Replace(tmpstr,"%","_")
  tmpstr = tmpstr & "_" & num & ".xml"
  getXmlFileName = tmpstr
 End Function
 
 Rem 公共方法 将数据写入xml文件
 Public Function WriteDataToXml
  If m_CacheType = 1 Then
   WriteListAndSearchDataToXml
  Else
   WriteContentDataToXml
  End If
 End Function

 Rem 写具体某条信息的详情xml
 Private Function WriteContentDataToXml
  Rem xml未过期则直接退出
  Dim xmlfile
  xmlfile = m_XmlFile
  If FSOExistsFile(xmlfile) Then
   If Not isXmlCacheExpired(xmlfile,m_CacheTime) Then  Exit Function
  End If
  Dim rs
  Set rs = Server.CreateObject("Adodb.Recordset")
  Rs.open m_sql,m_DataConn
  CreateContentXmlFile xmlfile,Rs
 End Function

 Rem 列表和搜索xml数据
 Private Function WriteListAndSearchDataToXml
 
  Dim sPagesize,TotalPage,CurPage,TotalRec
  sPagesize = m_PageSize * m_CachePageNum
  m_CurPage = CLng(m_CurPage)
 
  If m_CurPage Mod m_CachePageNum = 0 Then
   CurPage = m_CurPage/m_CachePageNum
  Else
   CurPage = int(clng(m_CurPage)/m_CachePageNum)+1
  End If
  Dim xmlfile
  xmlfile = getXmlFileName(CurPage)
  Rem 如果xml未过期则直接退出
  If FSOExistsFile(xmlfile) Then
   If Not isXmlCacheExpired(xmlfile,m_CacheTime) Then  Exit Function
  End If
  Dim rs
  Set Rs = Server.CreateObject("Adodb.Recordset")
  Rs.open m_sql,m_DataConn,1
  TotalRec = rs.recordcount
  rs.pagesize = sPagesize
  If  CurPage>rs.PageCount Then  CurPage = rs.PageCount
  CreateListAndSearchXMLFile xmlfile,TotalRec,Rs,sPagesize
 End Function
 
 Rem 私有方法
 Rem 得到文件的最后修改时间
 Private Function FSOGetFileLastModifiedTime(file)
  Dim fso,f,s  
  Set fso=CreateObject("Scripting.FileSystemObject")  
  Set f=fso.GetFile(file)  
  FSOGetFileLastModifiedTime = f.DateLastModified
  Set f = Nothing
  Set fso = Nothing
 End Function

 Rem 判断xml缓存是否到期
 Private Function isXmlCacheExpired(file,seconds)
  Dim filelasttime
  filelasttime = FSOGetFileLastModifiedTime(file)
  If DateAdd("s",seconds,filelasttime) < Now Then
   isXmlCacheExpired = True
  Else
   isXmlCacheExpired = False
  End If
 End Function
 Rem 文件是否存在
 Private Function FSOExistsFile(file)
  Dim fso
  Set fso = Server.CreateObject("Scripting.FileSystemObject")
  If fso.FileExists(file) Then
   FSOExistsFile = true
  Else
   FSOExistsFile = false
  End If
  Set fso = nothing
 End Function
 
 Rem 生成详细数据的xml
 Private Function CreateContentXmlFile(xmlfile,Rs)
  Dim xmlcontent
  xmlcontent = "<?xml version=""1.0"" encoding=""gb2312""?>" & vbnewline
  xmlcontent = xmlcontent & "<root>" & vbnewline
 
  Dim field
  For Each field In rs.Fields
   xmlcontent = xmlcontent & "<"&field.name&">"
   Dim value
   value = field.value
   If TypeName(value) = "String" Then
    xmlcontent = xmlcontent & "<![CDATA[" & Trim(value) & "]]>"
   Else
    xmlcontent = xmlcontent &  Trim(value)
   End If
   xmlcontent = xmlcontent & "</"&field.name&">" & vbnewline
  Next
  rs.close
  Set rs = Nothing
  xmlcontent = xmlcontent & "</root>" & vbnewline
 
  Dim folderpath
  folderpath = Trim(left(xmlfile,InstrRev(xmlfile,"\")-1))
  Call CreateDIR(folderpath&"") '创建文件夹
  WriteStringToXMLFile xmlfile,xmlcontent
 End Function

 Rem 生成列表的xml
 Private Function CreateListAndSearchXMLFile(xmlfile,TotalRec,Rs,sPagesize)
  Dim xmlcontent
  xmlcontent = ""
  xmlcontent = xmlcontent & "<?xml version=""1.0"" encoding=""gb2312""?>" & vbnewline
  xmlcontent = xmlcontent & " <root>" & vbnewline
  xmlcontent = xmlcontent & "  <totalrec>" & TotalRec & "</totalrec>" & vbnewline
  Dim k
  k = 0
  Dim field
  While Not rs.eof and k<sPagesize
   xmlcontent = xmlcontent & "  <item "
   For Each field In rs.Fields
    xmlcontent = xmlcontent & field.name & "=""" & XMLStringEnCode(field.value) & """ "
   Next
   xmlcontent = xmlcontent &  "></item>" & vbnewline
   rs.movenext
   k=k+1
  Wend
  rs.close
  Set rs = Nothing
  xmlcontent = xmlcontent & " </root>" & vbnewline
  Dim folderpath
  folderpath = Trim(left(xmlfile,InstrRev(xmlfile,"\")-1))
  Call CreateDIR(folderpath&"") '创建文件夹
  WriteStringToXMLFile xmlfile,xmlcontent
 End Function
 Rem xml转义字符
 Private Function XMLStringEnCode(str)
  If str&"" = "" Then XMLStringEnCode="":Exit Function
  str = Replace(str,"<","&lt;")
  str = Replace(str,">","&gt;")
  str = Replace(str,"'","&apos;")
  str = Replace(str,"""","&quot;")
  str = Replace(str,"&","&amp;")
  XMLStringEnCode = str
 End Function
 Rem 写文件
 Private Sub WriteStringToXMLFile(filename,str)
  'On Error Resume Next
  Dim fs,ts
  Set fs= createobject("scripting.filesystemobject")
  If Not IsObject(fs) Then Exit Sub  
  Set ts=fs.OpenTextFile(filename,2,True)
  ts.writeline(str)
  ts.close
  Set ts=Nothing
  Set fs=Nothing
 End Sub

 Rem 创建文件夹
 Private function CreateDIR(byval LocalPath)
  On  Error  Resume  Next
  Dim i,FileObject,patharr,path_level,pathtmp,cpath
  LocalPath = Replace(LocalPath,"\","/")
  Set  FileObject = server.createobject("Scripting.FileSystemObject")
  patharr = Split(LocalPath,"/")
  path_level = UBound (patharr)
  For  i = 0 To  path_level
   If  i=0 Then 
    pathtmp=patharr(0) & "/"
   Else 
    pathtmp = pathtmp & patharr(i) & "/"
   End If
   cpath = left(pathtmp,len(pathtmp)-1)
   If  Not  FileObject.FolderExists(cpath) Then
    'Response.write cpath
    FileObject.CreateFolder cpath
   End  If
  Next
  Set  FileObject = Nothing
  If  err.number<>0 Then
   CreateDIR = False
   err.Clear
  Else
   CreateDIR = True
  End  If
 End  Function
End Class
%>

此类包含两种缓存方式：一种是基于列表方式的，如按照某个类别显示信息、搜索某个关键词进行显示；另外一种是详细页面的缓存，如显示具体的某篇文章。
此类与具体的业务逻辑无关，只负责xml数据的读取和存储，判断是否缓存过期决定是否需要更新缓存。按照三层构架模式的话，它处于数据访问层。

调用这个类的代码：
Business.asp
<%
Rem xml数据缓存类业务逻辑层代码
'--------------------------------------------------
'转载的时候请保留版权信息
'作者:walkman
'网址:手机主题 http://www.shouji138.com
'版本:ver1.0
'欢迎各位交流进步
'--------------------------------------------------
Rem 根据classid取列表数据
Function GetListarr(classid,curpage,PageSize,CachePageNum,ByRef RecordCount)
 openConn
 Dim sql
 sql = "select thmid,thmname,picfileurl,win_theme.adddate from win_theme where  win_theme.ClassID="&classid&" order by thmid desc"
 Dim cache
 Set cache = new XmlCacheCls
 cache.PageSize = PageSize     '每页N条记录
 cache.CachePageNum = CachePageNum    '一个xml文件缓存M页的数据量
 cache.XmlFile = Server.Mappath("xmlcache/classxml/list_"&classid&".xml")
 cache.Sql = sql
 cache.CurPage = curpage
 cache.CacheType = 1
 Set cache.Conn = conn
 cache.ReadData
 Dim SqlArr
 SQLArr = cache.SQLArr
 RecordCount = cache.RecordCount
 Set cache = Nothing
 GetListarr = SqlArr
End Function

Rem 根据classid生成xml缓存
Function CreateListxml(classid,curpage,PageSize,CachePageNum,CacheTime)
 Dim sql
 sql = "select thmid,thmname,picfileurl,win_theme.adddate from win_theme where  win_theme.ClassID="&classid&" order by thmid desc"
 Dim cache
 Set cache = new XmlCacheCls
 cache.CacheTime = CacheTime '缓存时间
 cache.PageSize = PageSize     '每页N条记录
 cache.CachePageNum = CachePageNum    '一个xml文件缓存M页的数据量
 cache.XmlFile = Server.Mappath("xmlcache/classxml/list_"&classid&".xml")
 cache.Sql = sql
 cache.CurPage = curpage
 cache.CacheType = 1
 Set cache.Conn = conn
 cache.WriteDataToXml
 Set cache = Nothing
End Function

Rem 根据keyword取列表数据
Function GetSearcharr(keyword,curpage,PageSize,CachePageNum,ByRef RecordCount)
 openConn
 Dim sql
 Dim sqlkey
 sqlkey = Replace(keyword,"'","")
 sql = "select thmid,thmname,picfileurl,win_theme.adddate from win_theme where  ThmName like '%"&sqlkey&"%' or ThmRange  like '%"&sqlkey&"%' or ThmInstro  like '%"&sqlkey&"%'  order by thmid desc"
 Dim cache
 Set cache = new XmlCacheCls
 cache.PageSize = PageSize     '每页N条记录
 cache.CachePageNum = CachePageNum    '一个xml文件缓存M页的数据量
 cache.XmlFile = Server.Mappath("xmlcache/searchxml/list_"&Server.URlEncode(Replace(keyword,"'",""))&".xml")
 cache.Sql = sql
 cache.CurPage = curpage
 cache.CacheType = 1
 Set cache.Conn = conn
 cache.ReadData
 Dim SqlArr
 SQLArr = cache.SQLArr
 RecordCount = cache.RecordCount
 Set cache = Nothing
 GetSearcharr = SqlArr
End Function
 
Rem 根据keyword生成xml缓存
Function CreateSearchxml(keyword,curpage,PageSize,CachePageNum,CacheTime)
 Dim sql
 Dim sqlkey
 sqlkey = Replace(keyword,"'","")
 sql = "select thmid,thmname,picfileurl,win_theme.adddate from win_theme where  ThmName like '%"&sqlkey&"%' or ThmRange  like '%"&sqlkey&"%' or ThmInstro  like '%"&sqlkey&"%'  order by thmid desc"
 Dim cache
 Set cache = new XmlCacheCls
 cache.CacheTime = CacheTime '缓存时间
 cache.PageSize = PageSize     '每页N条记录
 cache.CachePageNum = CachePageNum    '一个xml文件缓存M页的数据量
 cache.XmlFile =  Server.Mappath("xmlcache/searchxml/list_"&Server.URlEncode(Replace(keyword,"'",""))&".xml")
 cache.Sql = sql
 cache.CurPage = curpage
 cache.CacheType = 1
 Set cache.Conn = conn
 cache.WriteDataToXml
 Set cache = Nothing
End Function
Rem 根据classid取列表数据
Function GetDetailarr(thmid)
 openConn
 Dim sql
 sql = "select a.thmid,a.thmname,a.classid,b.classname,a.picfileurl,a.thmver,a.thmsize,a.thminstro,a.thmrange,a.thmfileurl,a.adddate from win_theme a,Win_Classify b where a.classid=b.classid and  a.thmid="&thmid&""
 Dim thmidmod
 thmidmod = thmid Mod 100
 
 Dim cache
 Set cache = new XmlCacheCls
 cache.XmlFile = Server.Mappath("xmlcache/detailxml/"&thmidmod&"/"&thmid&".xml")
 cache.Sql = sql
 cache.CacheType = 2
 Set cache.Conn = conn
 cache.ReadData
 Dim SqlArr
 SQLArr = cache.SQLArr
 Set cache = Nothing
 GetDetailarr = SqlArr
End Function
Rem 根据keyword生成xml缓存
Function CreateDetailxml(thmid,CacheTime)
 Dim sql
 sql = "select a.thmid,a.thmname,a.classid,b.classname,a.picfileurl,a.thmver,a.thmsize,a.thminstro,a.thmrange,a.thmfileurl,a.adddate from win_theme a,Win_Classify b where a.classid=b.classid and  a.thmid="&thmid&""
 Dim thmidmod
 thmidmod = thmid Mod 100
 Dim cache
 Set cache = new XmlCacheCls
 cache.CacheTime = CacheTime '缓存时间
 cache.XmlFile =  Server.Mappath("xmlcache/detailxml/"&thmidmod&"/"&thmid&".xml")
 cache.Sql = sql
 cache.CacheType = 2
 Set cache.Conn = conn
 cache.WriteDataToXml
 Set cache = Nothing
End Function

Rem 检测动态数组是否已分配
Function   ismalloc(a)
 On   Error Resume Next
 Dim   i  
 i   =   UBound(a)
 If Err Then
 ismalloc = False
 Else
 ismalloc   =   True  
 End If 
End   Function 
 
Function showData(SQLArr)
 If Not  ismalloc(SQLArr) Then Exit Function
 Dim i,k
 Dim num
 num = 0
 i = UBound(SQLArr,1)
 k = UBound(SQLArr,2)
 Dim m,n
 For m = 0 To k
  num = num+1
 %>
 <ul class="listbox" onMouseOver="overtb(this)" onMouseOut="outtb(this)">
<li>
<a title="<%=SQLArr(1,m)%>" href="detail.asp?id=<%=SQLArr(0,m)%>" target="_blank">
  <img height="140" alt="<%=SQLArr(1,m)%>" src="http://www.shouji138.com<%=SQLArr(2,m)%>" width="107" border="0"></a>
</li>
<li class="green bold">
<a title="<%=SQLArr(1,m)%>" href="detail.asp?id=<%=SQLArr(0,m)%>" target="_blank">
<%=walkgottopic(Trim(SQLArr(1,m)),18)%></a>
</li>
 <li><%=DateValue(SQLArr(3,m))%></li>
 </ul>
 <%
 next
End Function
%>
这个文件是业务逻辑层代码，负责根据不同的业务逻辑来实现xml数据的读取和写入，并提供接口方法给web表现层调用。
具体的调用代码：
list.asp
只显示相关代码。
<%
。。。。。。
Dim classid
classid = Request("classid")
If classid = "" Or (Not IsNumeric(classid)) Then Response.write "参数错误！":Response.End()
classid = CLng(classid)
Dim sPagesize,TotalPage,CurPage,TotalRec,CachePageNum
sPagesize = 20
CachePageNum = 10
CurPage = Trim(Request("page"))
IF CurPage="" Or (Not IsNumeric(CurPage)) Then
  CurPage=1
Else
  CurPage=Clng(CurPage)
End IF
Dim myarr
myarr = GetListarr(classid,CurPage,sPagesize,CachePageNum,TotalRec)
'总页数
TotalPage = int(clng(TotalRec)/sPagesize*-1)*-1
If Clng(TotalRec)>0 Then
 showData myarr
End If
................
%>
最后在页面最底部调用一个asp的script语句来更新xml缓存。
<script type="text/javascript" src="setcache.asp?action=list&curpage=<%=curpage%>&classid=<%=classid%>"></script>

setcache.asp
相关代码
<%
openconn
Dim action
action = Trim(Request("action"))&""
Dim curpage
curpage = Request("curpage")
Dim classid
Dim keyword
Dim thmid
If action = "list" Then
 classid = Request("classid")
 If classid="" Or (Not IsNumeric(classid)) Or curpage="" Or (Not IsNumeric(curpage)) Then
 Else
  CreateListxml CLng(classid),CLng(curpage),20,10,60 * 60 * 2  '创建分类的xml
 End If
ElseIf action = "search" Then
 keyword = Trim(Request("keyword"))
 If keyword=""  Then
 Else
  CreateSearchxml keyword,CLng(curpage),20,10,60 * 60 * 2  '创建搜索的xml
 End If
ElseIf action = "detail" Then
 thmid = Request("id")
 If thmid="" Or (Not IsNumeric(thmid))  Then
 Else
  CreateDetailxml CLng(thmid),60 * 60 * 2  '创建详情的xml
 End If
End If
Call Closeconn
Response.write " "
Response.End
%>
至此，核心代码都分享出来了，实践证明，通过这样的方式，我的138手机主题网的服务器的CPU占用率和内存占用率明显下降，访问速度也明显提高，从以前的需要几秒甚至10多秒，到现在只需要10几毫秒。
为了方便大家理解其中的代码，我特地做了一个demo，供同行学习交流。地址：http://www.shouji138.com/aspnet2/demo
此例程的完整下载包：http://www.shouji138.com/aspnet2/demo/xmlcachedemo.rar
本人QQ:441003232 欢迎大家交流共同进步。
也可以访问本人的小站：手机主题:http://www.shouji138.com