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,"<","<") str = Replace(str,">",">") str = Replace(str,"'","'") str = Replace(str,"""",""") str = Replace(str,"&","&") 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
