ASP实例：利用缓存提高数据显示效率
实例演示.先建立一个简单的,写个function读取一下,写入一个dim变量temp中:
asp代码
<%
function displayrecords()
dim sql, conn, rs
sql = "select id, [szd_f], [szd_t] from admin"
set conn = server.createobject("adodb.connection")
conn.open "driver={microsoft access driver (*.mdb)}; dbq="&server.mappath("db.mdb")
set rs = server.createobject("adodb.recordset")
rs.open sql, conn, 1, 3
if not rs.eof then
dim temp
temp = "<table width=""90%"" align=""center"""
temp = temp & " border=""1"" bordercolor=""silver"""
temp = temp & " cellspacing=""2"" cellpadding=""0"">"
temp = temp & "<tr bgcolor=""#ccddee""><td width=""5%"""
temp = temp & ">id</td><td>操作</td>"
temp = temp & "<td>数值</td></tr>"
while not rs.eof
temp = temp & "<tr><td bgcolor=""#ccddee"">"
temp = temp & rs("id") & "</td><td>" & rs("szd_f")
temp = temp & "</td><td>" & rs("szd_t")
temp = temp & "</td></tr>"
rs.movenext
wend
temp = temp & "</table>"
displayrecords = temp
else
displayrecords = "data not available."
end if
rs.close
conn.close
set rs = nothing
set conn = nothing
end function
写入缓存
function displaycachedrecords(secs)
dim retval, datval, temp1
retval = application("cache_demo")
datval = application("cache_demo_date")
if datval = "" then
datval = dateadd("s",secs,now)
end if
temp1 = datediff("s", now, datval)
if temp1 > 0 and retval <> "" then
displaycachedrecords = retval
debugging code :
response.write "<b><font color=""green"">利用缓存读取数据"
response.write " ... (" & temp1 & " 秒剩余)</font></b>"
response.write "<br><br>"
else
dim temp2
change displayrecords() to the function whose
value you want to cache
temp2 = displayrecords()
application.lock
application("cache_demo") = temp2
application("cache_demo_date") = dateadd("s",secs,now)
application.unlock
displaycachedrecords = temp2
debugging code :
response.write "<b><font color=""red"">刷新缓存显示 ..."
response.write "</font></b><br><br>"
end if
end function
%>
<!--
response.write displayrecords()
-->
<html>
<head>
<title>利用缓存从数据库---读取数据</title>
<style>
body, p, td { font-family:sans-serif; font-size:8pt; }
td { padding-left: 5; }
</style>
</head>
<body>
<%
dim t1, t2
t1 = timer
response.write displaycachedrecords(20)
t2 = timer
%>
<p align="center">
停留时间: <%= left((cdbl((t2 - t1) * 1000.0)), 5) %> ms
</p>
</body>
</html>