外文翻译ajax方法和服务器端技术

外文原文来源MASTERINGAJAX14AUG2007FROMOREILLYMEDIAINC4AJAXANDTHESEVERSIDETECHNOLOGLESYOUDBEFORGIVENATTHISPOINTFORTHINKINGTHATAJAXISALLABOUTWHATHAPPENSONTHECLIENTSIDEINTHEINITIALDEFINITONOFAJAX,THETERM“WITHINPUTFROMTHESERVER”WASTHEIMPORTANTCAVEATINFACT,MANYAJAXDEVELOPERSWOULDCONSIDERANAPPLICATIONTHATUSESXMLHTTPREQUESTTOUPDATETHEPAGEWITHOUTANYINPUTFROMTHESERVERNOTTOBEANAJAXAPPLICATIONATALLSOFAR,THEDISCUSSIONSHAVEAVOIDEDTALKINGABOUTTHEOTHERSIDEOFTHECLIENT/SERVERCOMMUNICATIONTHESERVERSIDEINREALITY,THOUGH,THISISLIKEHAVINGAPHONECALLANDCONDUCTINGACONVERSATIONWITHOUTBEINGABLETOHEARTHEOTHERPERSONSPEAKINFACT,THEFIRSTTWOCHAPTERSOFTHISBOOKHAVENOTUSEDANYSERVERSIDECODETHISISASTATEOFAFFAIRSTHATCANNOTCONTINUEONEOFTHEINITIALGOALSOFTHISBOOKHASBEENTOREMAINAGNOSTICANDAMBIVALENTABOUTTELLINGYOUWHICHSERVERSIDETECHNOLOGYTOUSEINFACT,THEDISCUSSIONINTHISCHAPTERASSUMESTHATYOUALREADYHAVEMADEYOUCHOICETHEREFORE,TELLINGYOUWHICHONETHEAUTHORSPREFERISONLYGOINGTOANTAGONIZEONEOFTHEGREATADVANTAGESOFUSINGAJAXTECHNIQUESISTHATYOUSHOULDBEABLETOFITANYSERVERSIDETECHNOLOGYINTOYOURAJAXAPPLICATIONSWITHEASETHISCHAPTERDEMONSTRATESTHISTHEWAYINWHICHAJAXREADTHEXMLHTTPREQUESTOBJECTCOMMUNICATESWITHTHESERVERISFUNDAMENTALLYTHESAMEFOREACHTECHNOLOGYBUTONCETHEINFORMATIONHASARRIVED,THEWAYINWHICHITISDEALTWITHDIFFERSALITTLEFOREACHTECHNOLOGYITSEVIDENTTHATITSNOTPOSSIBLETOTOUCHONALLDEALTWITHDIFFERSALITTLEFOREACHTECHNOLOGYITEVIDENTTHATITSNOTPOSSIBLETOTOUCHONALLSERVERSIDETECHNOLOGIESINTHISCHAPTER,SOTHEAUTHORSSELECTEDTHETHREECONSIDEREDTOBETHEMOSTCOMMONANDMOSTPERTINENTTOTHEAJAXDEVELOPERASPNET,PHP,ANDJAVAIFYOUWORKWITHANOTHERTECHNOLOGY,THENYOUSHOULDBEABLETOLOOKATTHEPATTERNSHEREANDGLEANHOWYOUMIGHTGETTHEINFORMATIONBACKTHISDISCUSSIONDOESNOTGOINTOMASSIVEDETAILABOUTHOWEACHOFTHESETECHNOLOGIESWORKS,NORDOESITTEACHYOUTHEINSANDOUTSOFSYNTAXORUSAGERATHER,THISCHAPTERCUTSTOTHECHASEANDPROVIDESANEXAMPLEOFHOWANAJAXAPPLICATIONCANMESHWITHEACHTECHNOLOGYANDHOWTHATPARTICULARSERVERSIDETECHNOLOGYCANRELAYINFORMATIONANDDATA,WHICHCANBEUSEDINTHEAPPLICATION,BACKTOTHECLIENTINDEPENDENTUSERCONTROLSCONCEPTUALLY,TWOTYPESOFUSERCONTROLSEXISTINDEPENDENTANDINTEGRATEDINDEPENDENTUSERCONTROLSDONTINTERACTWITHTHERESTOFTHECODEONYOURFORMTHEFOOTERUSERCONTROLISONESUCHEXAMPLEANOTHEREXAMPLEMIGHTBEALINKMENUCONTROLTHATCONTAINSALISTOFBUTTONSOFFERINGLINKSTOOTHERPAGESTHISLINKMENUUSERCONTROLCANHANDLETHEEVENTSFORALLTHEBUTTONSANDTHENRUNTHEAPPROPRIATERESPONSEREDIRECTCODETOMOVETOANOTHERWEBPAGEORITCANJUSTBEANORDINARYHYPERLINKCONTROLTHATDOESNTHAVEANYASSOCIATEDSERVERSIDECODEEVERYPAGEINTHEWEBSITECANTHENINCLUDETHESAMELINKMENUUSERCONTROL,ENABLINGPAINLESSWEBSITENAVIGATIONWITHNONEEDTOWORRYABOUTFRAMESNOTEYOUCANUSETHEMOREFEATURERICHNAVIGATIONCONTROLSTOPROVIDEWEBSITENAVIGATIONCREATINGYOUROWNCUSTOMCONTROLSGIVESYOUASIMPLE,MOREFLEXIBLE,BUTLESSPOWERFULAPPROACHTOPROVIDINGNAVIGATIONYOUMIGHTUSECUSTOMCONTROLSRATHERTHANAWHOLESITEMAPFORSTRAIGHTFORWARDNAVIGATIONBETWEENAFEWPAGESTHEFOLLOWINGSAMPLEDEFINESASIMPLECONTROLTHATPRESENTSANATTRACTIVELYFORMATTEDLISTOFLINKSNOTETHATTHESTYLEATTRIBUTEOFTHETAGWHICHDEFINESFONTSANDFORMATTINGHASBEENOMITTEDFORCLARITYTHELINKSDONTACTUALLYTRIGGERANYSERVERSIDECODEINSTEAD,THEYRENDERTHEMSELVESASORDINARYHTMLANCHORTAGSWITHAHARDCODEDURLTOTESTTHISMENU,YOUCANUSETHEFOLLOWINGMENUHOSTASPXWEBPAGEITINCLUDESTWOCONTROLSTHEMENUCONTROLANDALABELCONTROLTHATDISPLAYSTHEPRODUCTQUERYSTRINGPARAMETERBOTHAREPOSITIONEDUSINGATABLEWHENTHEMENUHOSTASPXPAGELOADS,ITADDSTHEAPPROPRIATEINFORMATIONTOTHELBLSELECTIONCONTROLYOUCOULDUSETHELINKMENUCONTROLTOREPEATTHESAMEMENUONSEVERALPAGESTHISISPARTICULARLYHANDYINASITUATIONWHEREYOUCANTUSEMASTERPAGESTOSTANDARDIZELAYOUTPOSSIBLYBECAUSETHEPAGESARETOODIFFERENTWRITERINTHEUSEOFBEFOREOROUTPUTSTREAM,HTTPHEADSHOULDBESETHTTPSERVLETRESPONSETOPROVIDESUCHAMETHODCANBEUSEDAFTERTHEWRITEROROUTPUTSTREAMWILLRESPONDBACKTOTHEMAINPARTOFTHEUSERTOTURNOFFAFTERTHECOMPLETIONOFWRITEROROUTPUTSTREAMTOALLOWTHESERVERTORESPONDTOALREADYKNOWFINISHEDEVENTSTHETWOMODELSOFPROGRAMEXECUTIONWHICHARENOTNECESSARILYMUTUALLYEXCLUSIVEARELINEARANDEVENTDRIVENTHEKEYTOUNDERSTANDINGASPNETISTHATITISEVENTDRIVENLINEARPROGRAMSMOVEFROMSTEP1,TOSTEP2,ANDSOON,TOTHEENDOFALLTHESTEPSFLOWCONTROLSTRUCTURESWITHINTHECODESUCHASLOOPS,IFSTATEMENTS,ORMETHODCALLSMAYREDIRECTTHEFLOWOFTHEPROGRAM,BUTESSENTIALLY,ONCETHEPROGRAMEXECUTIONBEGINS,ITRUNSITSCOURSEUNAFFECTEDBYANYTHINGTHEUSERORSYSTEMMAYDOBEFOREGUIENVIRONMENTS,MOSTCOMPUTERPROGRAMSWERELINEARINCONTRAST,EVENTDRIVENPROGRAMMINGRESPONDSTOSOMETHINGHAPPENINGSUCHASABUTTONBEINGPRESSEDMOSTOFTEN,EVENTSAREGENERATEDBYUSERACTION,BUTEVENTSCANBERAISEDBYTHESYSTEMFOREXAMPLE,THESYSTEMMIGHTRAISEANEVENTWHENAFILETHATYOUOPENFORREADINGHASBEENREADINTOMEMORYORWHENYOURBATTERYSPOWERISRUNNINGLOWINASPNET,OBJECTSMAYRAISEEVENTSANDOTHEROBJECTSMAYHAVEASSIGNEDEVENTHANDLERSFOREXAMPLE,ABUTTONMAYRAISETHECLICKEVENT,ANDTHEPAGEMAYHAVEAMETHODTOHANDLETHEBUTTONSCLICKEVENTSUCHASBUTTON1_CLICKYOURCODEINTHEEVENTHANDLERTHENRESPONDSTOTHEBUTTONSBEINGCLICKEDINWHATEVERWAYISAPPROPRIATEFORYOURAPPLICATIONTHEMAINPOINTTOREMEMBERHEREISTHATSERVERCONTROLSAREOBJECTSTHATCANRAISEEVENTSANYACTIONAUSERTAKESWITHASERVERCONTROLONTHEBROWSERRAISESANEVENTYOURSERVERSIDECODERESPONDSTOTHATEVENT,RUNNINGTHECODEYOUHAVEPLACEDINTHEEVENTHANDLERMETHODTHEWEBSERVICESSTANDARDSHAVELONGSPECIFIEDUSINGSOAPTOSENDANDRECEIVEDATAFROMAWEBSERVICETHEPROBLEMISTHATYOUCANTJUSTATTACHDATAITQUERYSTRING,ORSTUFFITINTHEBODYOFTHEDOCUMENTWITHSOAPYOUHAVETOCREATEASPECIFICSOAPDOCUMENTFIRSTSOAPMESSAGESARENORMALXMLDOCUMENTSTHEYHAVEPARTICULARTAGSINDICATINGWHICHSECTIONOFTHEXMLDOCUMENTISTHEHEADERANDWHICHSECTIONOFTHEDOCUMENTBODYOFTHEMESSAGEALSO,IFYOUSENDSOAPMESSAGESTOAWEBSERVICE,THENYOUGETBACKMESSAGESINASOAPFORMATFROMTHEWEBSERVICE,ANDDISENTANGLINGTHERESPONSECANBEABITMORECOMPLEXTHANWITHJUSTASTRAIGHTFORWARDXMLDOCUMENTTHEADVANTAGEOFSOAPISTHATITALLOWSTHEDOCUMENTTOCONTAINMOREINSTRUCTIONSTHANITTYPICALLYCOULDOTHERWISEWHENYOUARELEARNINGABOUTWEBSERVICES,THOUGH,SOAPINTRODUCESALAYEROFOBFUSCATIONTHATYOUREBETTEROFFWITHOUTSOAPHASACTUALLYSPARKEDOFFANOTHERHEATEDSETOFDEBATESONTHEWEB,WHEREPEOPLEESPOUSEUSINGTHEHTTPMETHODSCOININGTHETERMRESTAGAINSTTHEMORECONVOLUTEDSOAPAPPROACH4AJAX方法和服务器端技术此时此刻，对于初学者而言，还应考虑如何再客户端上运行AJAX方法，AJAX再最初阶段被解释定义为很重要的警告可以从服务器端输入是。实际上许多AJAX方法的发明者再使用XMLHTTPREQUEST来更新网页输入的程序时，不考虑任何从AJAX服务中的输入。到目前为止，有关会话已经提及到关于客户端/服务器的交流（即服务器端）的另外一面。确切的说这就像是打电话和使用无法听到对方声音的会话。这本书的前两个章节，并没有使用服务器端代码，而此时如果不使用服务器端代码，个人的业务将无法继续进行。在这本书中，一个最重要的要点是要保持再叙述服务器端技术时一些较为模糊或者很难理解的一些技术上的应用。在这一章所介绍的知识将解决用户的这一问题,也就是往往会造成用户再阅读其他书时对书本产生迷惑之处。AJAX最大的优点也是最重要一点是可以将AJAX技术推广运用在任何服务器端，以下内容将所探讨的就是主要针对将AJAX技术运用在服务器端这一问题。在运用AJAX技术与服务器进行会话时，基本上与使用其他技术与服务器进行会话没有什么本质上的差别，显而易见的如果要是想使信息运用下面这个章节所介绍的服务器端技术传送到所需的位置，是不可能实现的，所以用户通常使用以下三种有关于AJAX的应用程序来进行程序的执行，即ASPNET技术平台,PHP技术,JAVA技术。如果你想使用除以上三种以外的其它技术来进行程序的执行，则需要再程序执行时，对当前程序执行的形式和信息每次回执的方式进行考虑，不过此类方法并不运用于再使用再使用任意一种方法来执行，在此同时，在一些语句或语法的输入/输出时也不会给予相应的提示。实际上，有一些问题例如关于AJAX应用程序平台如何来使用每个技术方法进行程序的处理一般情况下的服务器端代码如何对信息和执行日志进行回执的操作；又或者再说明情况下，被运用于应用程序的信息会被传送到客户端，上述这些类似问题，在此章节都会为读者进行详细的叙述，并逐个问题进行举例分析。静态的用户控件用户控件可以静态或动态添加到WEB页面中，静态用户控件不需要再窗体中放入太多的代码。页脚用户控件就是静态的用户控件。另外一个方法就是添加LINKMENU控件与BUTTON控件相结合来使用RESPONSEREDIRECT方法来实现页面之间的跳转。或者使用普通的超链接HYPERLINK控件，此类控件不需要一些隐藏的服务代码。每个页面都可以同时存在一个又相同功能的LINKMENU用户控件，也可以不必为网站导航的框架担心。注意你能使用较多导航控件设计网站导航。创建自定义用户控件给你们简单、更有人性化、但却是不是最有效的方法提供站点导航。再少量的页面中用户控件比整个的站点导航更为实用。下列的例子生动形象的呈现出一组简单的超连接控件的运用。注意，DIV标签是用来定义字型和格式，可以省略。超链接不是获取客户端和服务器的相关信息，相反的。它们是将HTTP相应数据及有关响应的信息重新定向到新的URL中。学会下面这个方法，你将会实现把一个菜单控件和一个LABLE控件通过一个TABLE同时运用再一个页面MENUHOSTASPX中。当MENUHOSTASPX进行加载的时候，它把适当的数据加入LBLSELECTION控件。你可以运用LINKMENU控件重复使用相同的菜单再多个页面中。可能是因为网页之间差别太大，当母版页做不到将页面标准化区分的时候，我们可以使用这种方法。为了响应客户端,一个HTTPSERVLETRESPONSE对象提供返回数据给用户的两个方法。你可以用GETWRITER方法返回，或者GETOUTPUTSTREAM方法以输出流返回。你应该用GETWRITER返回文本数据，而用GETOUTPUTSTREAM返回二进制数据