淘寶網(wǎng)表現(xiàn)層設(shè)計(jì)分析

1、淘寶網(wǎng)表現(xiàn)層設(shè)計(jì)分析前幾天突然發(fā)現(xiàn)淘寶網(wǎng)訪問(wèn)非常慢而且出錯(cuò)（出現(xiàn)異常），猜測(cè)是淘寶網(wǎng)在發(fā) 布新版本時(shí)出現(xiàn)錯(cuò)誤或是某個(gè)服務(wù)器出現(xiàn)異常。但淘寶網(wǎng)的工程師在輸出錯(cuò)誤時(shí) 生成了客戶端注釋掉的Java異常信息（包含在!-和一之間），雖然在畫面上是 看不到的，但查看源代碼就可以清楚的看到這個(gè)Java出錯(cuò)信息。淘寶網(wǎng)采用阿里巴巴自己開(kāi)發(fā)的一個(gè)MVC框架，動(dòng)態(tài)網(wǎng)頁(yè)（jhtml頁(yè)面）的通 用入是口 WebxcontrollerServlet，最終調(diào)用/執(zhí)行模版是在TemplateModule的 子類中完成的，然后在Module執(zhí)行完成后跳轉(zhuǎn)到一個(gè)視圖（JSP文件），在Servlet 和Module中是通過(guò)Val

2、ve的職責(zé)鏈處理。圖1淘寶網(wǎng)部分類圖一個(gè)Web請(qǐng)求的基本處理流程是：客戶端發(fā)出Web請(qǐng)求WebxControllerServletPerformScreenTemplateValveTemplateModule附（本文基于下面的異常分析）：Exception: com.alibaba.webx.WebxException: Failed to execute screen: home.MyTaobao （template:screen/home/myTaobao.vm)atcom.alibaba.webx.WebxControllerServlet.handleRequest(WebxCont

3、rollerServlet.java:111)atcom.alibaba.webx.controller.AbstractWebxControllerServlet.doGet(Abstr actWebxControllerServlet.java:113)at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)atorg.apache.catalina.core.ApplicationFilterC

4、ernalDoFilter(Appl icationFilterChain.java:290)atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF ilterChain.java:206)atcom.alibaba.webx.filter.rundata.RunDataFilter.doFilter(RunDataFilter. java:48)atcom.alibaba.webx.filter.AbstractFilter.doFilter(AbstractFilter.java:150)atorg.a

5、pache.catalina.core.ApplicationFilterCernalDoFilter(Appl icationFilterChain.java:235)atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF ilterChain.java:206)mon.webx.filter.RemoteAddrFilter.doFilter(RemoteAddrFil ter.java:16)atcom.alibaba.webx.filter.AbstractFilter.doFilter(Abstr

6、actFilter.java:150)atorg.apache.catalina.core.ApplicationFilterCernalDoFilter(Appl icationFilterChain.java:235)atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF ilterChain.java:206)atcom.alibaba.webx.filter.timer.TimerFilter.doFilter(TimerFilter.java:93)atcom.alibaba.webx.filte

7、r.AbstractFilter.doFilter(AbstractFilter.java:150)atorg.apache.catalina.core.ApplicationFilterCernalDoFilter(Appl icationFilterChain.java:235)atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF ilterChain.java:206)atorg.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHea

8、derFi lter.java:96)atorg.apache.catalina.core.ApplicationFilterCernalDoFilter(Appl icationFilterChain.java:235)atorg.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF ilterChain.java:206)atorg.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperV alve.java:230)atorg.apach

9、e.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)atorg.jboss.web.tomcat.security.SecurityAssociationValve.invoke(Securit yAssociationValve.java:179)atorg.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValv e.java:84)atorg.apache.catalina.core.StandardHostValve.

10、invoke(StandardHostValve.j ava:127)atorg.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.j ava:102)atorg.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedC onnectionValve.java:157)atorg.apache.catalina.core.StandardEngineValve.invoke(StandardEngineVal ve.java:109)atorg

11、.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.jav a:262)atorg.apache.coyote.ajp.AjpAprPcess(AjpAprProcessor.java:419)atorg.apache.coyote.ajp.AjpAprProtocol$AjpConnectionHcess(AjpAprProtocol.java:378).AprEndpoint$Worker.run(AprEndpoint.java:15 08)at java.lang.Thread.run(Thread.java:5

12、95)Caused by: com.alibaba.service.pipeline.PipelineException: Failed to execute screen: home.MyTaobao (template:screen/home/myTaobao.vm)atcom.alibaba.turbine.pipeline.PerformScreenTemplateValve.performScreen Module(PerformScreenTemplateValve.java:112)atcom.alibaba.turbine.pipeline.PerformScreenTempl

13、ateValve.invoke(Perfor mScreenTemplateValve.java:48)atcom.alibaba.turbine.pipeline.AbstractValve.invoke(AbstractValve.java:33)atcom.alibaba.service.pipeline.DefaultPipeline.invokeNext(DefaultPipeli ne.java:224)atcom.alibaba.service.pipeline.DefaultPipeline.invoke(DefaultPipeline.j ava:187)atcom.alib

14、aba.turbine.pipeline.ChooseValve$Condition.invokeSubPipeline( ChooseValve.java:82)atcom.alibaba.turbine.pipeline.ChooseValve.invoke(ChooseValve.java:57)atcom.alibaba.turbine.pipeline.AbstractValve.invoke(AbstractValve.java:33)atcom.alibaba.service.pipeline.DefaultPipeline.invokeNext(DefaultPipeli ne

15、.java:224)atcom.alibaba.service.pipeline.DefaultPipeline.invoke(DefaultPipeline.j ava:187)atcom.alibaba.service.pipeline.TryCatchFinallyValve.invokeTryPipeline(TryCatchFinallyValve.java:114)atcom.alibaba.webx.WebxControllerServlet.handleRequest(WebxControllerSe rvlet.java:108).33 moreCaused by: com.alibaba.webx.WebxException: MyTaobao Response is null or failedatcom.taobao.web.mytaobao.mo