supesite完美实现调用资讯显示缩略图.doc

supesite完美实现调用资讯显示缩略图本调用代码用于放置在首页中，列表模块带缓存，每个分页的缓存时间相差20秒，避免同一时间所有缓存全部失效，某一时刻非常缓慢的问题。列表数量统计的模块也带缓存。取所有频道的资讯文章，有缩略图显示缩略图，无缩略图显示无缩略图的文件。对比嵌套循环查询，极大减少数据库查询次数(嵌套查询可能达到11次数据库查询)，本方法只需查询一次数据库。列表模块对应的SQL语句为SELECT i.itemid,i.catid,i.uid,i.username,i.subject,i.dateline,i.viewnum,i.replynum,i.digest,i.top,i.picid,,n.message,a.thumbpath,a.subject AS a_subject FROM supe_spaceitems iINNER JOIN supe_spacenews nON i.itemid=n.itemid INNER JOIN supe_categories cON i.catid=c.catid LEFT JOIN supe_attachments aON i.picid=a.aid WHERE i.type=newsORDER BY i.top DESC,i.itemid DESC两个INNER JOIN内联一个LEFT JOIN左连接做四表联查，全部为主键或者索引查询，相对效率高。由于用了联查，block模块中的perpage分页代码无效，只能自己调用multi函数处理分页内容。分页数量统计对应的SQL语句为SELECT count(itemid)AS total FROMsupe_spaceitemsWHERE type=newscachename缓存以mynews_pagexx命名的变量，解决缓存覆盖问题。SupeSite 7.5，256M内存VPS服务器在每秒1000次并发压力下，关闭缓存平均页面执行时间为0.08秒，开启缓存平均0.006秒执行时间。完整调用代码如下：！-Article begin-div class=article！-eval$basecachetime=3500；/*设置本页面基础缓存时间*/-！-eval$baseperpage=10；/*设置本页面的单页文章数量*/-！-eval$mypage=$_SGETpage?$_SGETpage：1；-！-eval$mystart=($mypage-1)*$baseperpage-！-eval$mycachename=mynews_page.$mypage-！-eval$mycachetime=$basecachetime+$mystart*2-！-block name=spacenewsparameter=type/news/sql/SELECT%20i.itemid%2C%20i.catid%2C%20i.uid%2C%20i.username%2C%20i.subject%2C%20i.dateline%2C%20i.viewnum%2C%20i.replynum%2C%20i.digest%2C%20i.top%2C%20i.picid%2C%20%2C%20n.message%2C%20a.thumbpath%2C%20a.subject%20AS%20a_subject%0D%0AFROM%20supe_spaceitems%20i%0D%0AINNER%20JOIN%20supe_spacenews%20n%20ON%20i.itemid%20%3D%20n.itemid%0D%0AINNER%20JOIN%20supe_categories%20c%20ON%20i.catid%20%3D%20c.catid%0D%0ALEFT%20JOIN%20supe_attachments%20a%20ON%20i.picid%20%3D%20a.aid%0D%0AORDER%20BY%20i.top%20DESC%2C%20i.itemid%20DESC/limit/$mystart,$baseperpage/cachename/$mycachename/cachetime/$mycachetime/tpl/data-！-Thiese Block had cached in dollar_SBLOCK$mycachename-！-loop$_SBLOCK$mycachename$value-！-eval$valuemessage=trim(strip_tags($valuemessage)；-！-eval$valuemessage=trim(cutstr($valuemessage,290,1)；-！-if$valuetop-！-eval$valuesubject=置顶.$valuetop.$valuesubject；-！-/if-！-if$valuedigest-！-eval$valuesubject.=精华.$valuedigest.；-！-/if-div class=posth2 ahref=title=$valuesubject$valuesubject/a/h2 span class=pmentsem$valuereplynum/em个评论/span div class=clear/div！-if$valuethumbpath-a href=img src=title=$valuea_subjectalt=$valuea_subjectclass=thumb_image/a！-else-a href=img src=title=$valuesubjectalt=$valuesubjectclass=thumb_image/a！-/if-div class=pcontent$valuemessage/div div class=clear/div div class=pmeta#date(Y-m-d,$valuedateline)#/a href=title=$valuename$valuename/a/$valueviewnum浏览/div ahref=title=阅读全文class=readmore阅读全文/a/div！-/loop-！-Navigation begin-div class=page_navi！-翻页输出控制-！-eval$mylistcount=1；-！-block name=categoryparameter=sql/SELECT%20count%28%20itemid%20%29%20AS%20total%20FROM%20%60supe_spaceitems%60/limit/1/cachetime/$basecachetime/cachename/indexcount/tpl/data-！-Index listcount has cached in mylistcount-！-eval$mylistcount=$_SBLOCKindexcount0total；-！-if$mylistcount-！-eval$_SGETaction=index；-！-eval$myurlarr=$_SGET；-！-eval unset($myurlarrpage)；-！-eval$_SBLOCKmynews_multip