jsp動態(tài)網(wǎng)站技術(shù)-外文文獻(xiàn)翻譯大學(xué)論文

大學(xué)教務(wù)處第28頁JSPdynamicwebtechnologyJSP(JavaServerPages)isinitiatedbySunMicrosystems,Inc.,withmanycompaniestoparticipateintheestablishmentofadynamicwebpagetechnicalstandards.JSPtechnologysomewhatsimilartoASPtechnology,itisinthetraditionalHTMLpagesinthedocumentparagraphinsertedJAVAprocedures(Scriptlet)andJSPtag(tag),thusJSPdocuments.UsingJSPdevelopmentoftheWebapplicationiscross-platformthatcanrunonLinux,isalsoavailableforotheroperatingsystems.JSPtechnologytousetheJavaprogramminglanguagepreparedbythecategoryofXMLtagsandscriptlets,toproducedynamicpagespackageprocessinglogic.Pagealsovisitbytagsandscriptletsexistintheservicessideoftheresourcesoflogic.JSPpagelogicandwebpagedesignanddisplayseparation,supportreusablecomponent-baseddesign,Web-basedapplicationdevelopmentisrapidandeasy.WebserverinthefaceofvisitsJSPpagerequest,thefirstimplementationoftheproceduresof,andthentogetherwiththeresultsoftheimplementationofJSPdocumentsinHTMLcodewiththereturntothecustomer.InserttheJavaprogrammingoperationofthedatabasecanbere-orientedwebsites,inordertoachievetheestablishmentofdynamicpagesneededtofunction.

JSPandJavaServlet,isintheimplementationoftheserver,usuallyreturnedtotheclientisanHTMLtext,aslongastheclientbrowserwillbeabletovisit.JSP1.0specificationofthefinalversionislaunchedinSeptember1999,Decemberhasintroduced1.1specifications.AtpresentrelativelynewisJSP1.2norms,JSP2.0normsofthedrafthasalsobeenintroduced.JSPpagesfromHTMLcodeandJavacodeembeddedinoneofthecomponents.TheserverwasinthepagesofclientrequestsaftertheJavacodeandthenwillgeneratetheHTMLpagestoreturntotheclientbrowser.JavaServletJSPisthetechnicalfoundationandlarge-scaleWebapplicationdevelopmentneedsofJavaServletandJSPsupporttocomplete.JSPwiththeJavatechnologyeasytouse,fullyobject-oriented,andaplatform-independentandsecure,mainlyforallthecharacteristicsoftheInternet.

JSPdynamicwebsitedevelopmentandtechnology.EarlydynamicwebsitedevelopmentandtechnologyusingaCGI-BINinterface.DeveloperstowriteinterfaceswiththerelevantproceduresandaseparateWeb-basedapplications,thelatterthroughtheWebservertocalltheformer.Thisdevelopmenttechnologythereisaseriousexpansionoftheproblem-eachnewCGIproceduralrequirementsontheserveraddanewprocess.Ifmultipleuserswithaccesstotheprogram,theseprocesseswillrunoutoftheWebserveralltheresourcesavailable,untilitscollapse.InordertoovercomethedisadvantagesoftheproposedMicrosoftActiveServerPages(ASP)technology,whichusethe"plug-in"andAPIsimplifiesWebapplicationdevelopment.CGIandASPcomparedtoitsadvantagescanincludeHTMLtags,candirectlyaccessthedatabaseandtheuseofunlimitedexpansionoftheActiveXcontrol,sotheprocedureonthepreparationofamoreflexible.ButthetechnologyisbasicallylimitedtoMicrosoftoperatingsystemplatform,themainworkenvironmentisMicrosoft'sIISapplicationstructure,theASPtechnologycannoteasilyachievecross-platformWebserverprogramdevelopment.HypertextPreprocessor(HypertextPre-processor),PHPdynamicwebsitedevelopmentandtechnologysimilartoASP,isalsoakindofembeddedinHTMLdocumentserver-sidescriptinglanguage.MostofitsgrammarandC,Java,Perl,andothersimilarlanguageandformeditsownuniquestyle,useofthelanguageWebprogrammerscanquicklydevelopdynamicpages.PHPinmostUnixplatforms,GUN/LinuxandMicrosoftWindowsplatformcanrun.PHP'smainadvantagesare:easeofinstallation,thelearningprocesssimpledatabaseconnectionconvenience,compatibilitystrongexpansionofthestrongcanobject-orientedprogramming,andsoon.However,PHP,therearesomeweaknesses,mainlyPHPisaninterpretationoflanguage,nottosupportmulti-threadedstructure,thesupportplatformanddatabaseconnectionsarelimited,especiallyinsupportofthestandardswithregardtoinherentweaknesses,forsomee-commerceapplications,PHPisnotappropriate.TherearealsotechnologiessuchasJavaServletstechnology,makeuseofthetechnologycanbeeasilypreparedusingtheJavalanguageinteractiveserver-sidecode.AJavaServletsisaJava-basedtechnologyrunningontheserver-sideprogram(andAppletdifferent,thelatterrunninginthebrowser).DeveloperstowritesuchaJavaServlets,toreceivefromtheWebbrowser'sHTTPrequest,togenerateadynamicresponse(mayneedtoquerythedatabasetocompletesucharequest),thensendHTMLorXMLdocumentsresponsetothebrowser.Thetechnologyforordinarypagesdesignerstoeasilygraspitisverydifficult.Thisapproach,theentirepageintheJavaServletsaretobecreated.IfthedevelopersormanagerswanttoadjustWebpagesthathavetoeditandre-buildtheJavaServlets.SunMicrosystems(SunMicrosystemsInc.)InWebservers,applicationservers,thetradingsystemanddevelopmenttoolsproviderofbroadsupportandcooperation,integrationandbalancealreadyexistsintheJavaprogrammingenvironment(suchasJavaServletsandJavaBeans)Tosupportthetechnologyandtoolshaveanew,Web-basedapplicationdevelopmentmethods-JavaServerPagesTechnology(JSP).Thisdynamicwebsitedevelopmentandtechnologymainlyhavethefollowingcharacteristics:ToanyWeborapplicationserverrunningon;Fromtheapplicationoflogicanddisplaypages;Tocarryouttherapiddevelopmentandtesting;SimplifiesthedevelopmentofWeb-basedinteractiveapplicationsfortheprocess.JSPtechnologymethodsInordertofacilitatetherapidanddynamicdevelopmentofthesite,JSPinthefollowingareasmadeimprovements,makingitarapidestablishmentofcross-platformdynamicsite'spreferredoption.Willgenerateanddisplaythecontentsofseparation

UsingJSPtechnology,WebpagesanddeveloperscanuseHTMLorXMLlogodesignandformattingthefinalpages,andusetheJSPlogoorlegshadgenerateddynamiccontentonthepage(thecontentisbasedonchangesintherequest,forexample,requestaccountinformationAbottleofwineoraspecificprice,etc.).ContentgeneratedbythelogicofthelogoandpackagingJavaBeanscomponents,andtiedupinthescript,allofthescriptsintheserver-siderun.AsthecorelogicinthelogoandpackagingwasintheJavaBeans,Webpagedesignersandmanagementpersonnel,willbeabletoeditanduseJSPpagesandwillnotaffectthecontentgenerated.Intheserver,JSPengineexplainedJSPlogoandscript,generatedbythecontentoftherequest(forexample,byvisitingJavaBeanscomponents,theuseofJDBCtoaccessthedatabaseorcontain),andwillresultinHTML(orXML)pagesintheformofsendingBacktothebrowser.Thishelpstoprotectthemselvesfromthecode,canguaranteethatanyHTML-basedWebbrowser'scompleteavailability.

2.Reusablecomponents

ThevastmajorityofJSPpagesrelyonreusable,cross-platformcomponents(JavaBeansorEnterpriseJavaBeanscomponents)toimplementtheproceduresrequiredbytheapplicationofthecomplexityoftreatment.Developerstoshareandexchangetheimplementationofthegeneraloperationofthecomponents,ormakethesecomponentsformoreusersandgroupsusedbythecustomer.Component-basedmethodstoacceleratetheoveralldevelopmentprocessandenableorganizationsofallkindsintheirexistingskillsandoptimizetheresultsofdevelopmenteffortsinthebalance.

3.UseoflogoWebpagedevelopersarenotfamiliarwiththescriptinglanguageprogrammers.JSPtechnologypackagehasmanyfunctions,whichisineasy-to-use,XMLandJSPrelatedtotheidentificationofdynamiccontentgenerationneeds.JSPstandardlogotoaccessandexamplesofJavaBeanscomponents,componentattributesetorretrieve,downloadApplet,andtheimplementationofothermethodsmoredifficulttocodingandtime-consumingfunction.

4.Adaptationplatform

AlmostallplatformssupportJava,JSP+JavaBeansalmostallplatformsunimpededaccess.Fromaporttoanotherplatform,JSPandJavaBeansdonotevenhavetorecompile,becauseJavabytecodestandardsandareplatform-independent.

5.Databaseconnection

JavainthedatabaselinkingthetechnologyisJDBC,JavaprogramthroughJDBCdriveranddatabaselinkedtotheimplementationofenquiries,suchasdataextractionoperation.SunhasalsodevelopedaJDBC-ODBCbridge,useofthistechnologywithJavaprogramscanaccessthedatabaseODBCdriver,themajorityofdatabasesystemscomewithODBCdriver.Inaddition,throughthedevelopmentofthelogo,JSPtechnologycanbefurtherexpanded.Third-partydevelopersandotherpersonnelforthecommonfunctionscancreatetheirownlogofor.ThismakesWebpagedeveloperscanusefamiliartoolsandthesamelogoastheimplementationofspecificfeaturesofthecomponenttotheirwork.JSPtechnologyeasilyintegratedintoavarietyofapplicationsinarchitecture,tousetheexistingtoolsandskills,andbeextendedtosupportenterprise-classdistributedapplications.UseofJavatechnologyaspartofthefamily,andtheJava2(EnterpriseArchitecture)anintegralpartof,JSPtechnologycansupportthehighlycomplexWeb-basedapplications.JSPpagesbecauseofthebuilt-inscriptinglanguageisbasedonJava,andalloftheJSPpageshavebeencompiledintoJavaServlets,soJSPpageswithallthebenefitsofJavatechnology,includingrobuststoragemanagementandsecurity.AspartoftheJavaplatform,JSPwiththeJavaprogramminglanguage,"apreparation,theentireoperation"characteristics.

JSPapplicationofthemodel.JSPpagesusuallybeencompiledintoJavaServlets,thisisastandardJavaextension.PagesdeveloperstovisitalloftheJavaapplicationenvironment,totakeadvantageofJavatechnologyandtheexpansionofportability.Thismakesthenextpageofthecall,theserverwillbeveryquickresponse(whichavoidstheCGI-BINforeachHTTPrequesttogenerateanewprocess).JSPpagescancontainavarietyofdifferentapplicationsinarchitectureormodel,canbeusedbydifferentagreements,partsandcomponentsbytheformatoftheCommonwealth.BasedonthedynamicinformationdisseminationandJSPtechnologyisanopen,scalablecreatedynamicWebpagesstandards.Regardlessofwhatusedtocreatetools,developerscanuseJSPpagestocreateaportableWebapplications,indifferentWebserverapplicationstorunon.

JSP動態(tài)網(wǎng)站技術(shù)：JSP(JavaServerPages)是由SunMicrosystems公司倡導(dǎo)、許多公司參與一起建立的一種動態(tài)網(wǎng)頁技術(shù)標(biāo)準(zhǔn)。JSP技術(shù)有點(diǎn)類似ASP技術(shù)，它是在傳統(tǒng)的網(wǎng)頁HTML文件中插入JAVA程序段(Scriptlet)和JSP標(biāo)記(tag)，從而形成JSP文件。用JSP開發(fā)的Web應(yīng)用是跨平臺的，即能在Linux下運(yùn)行，也能在其他操作系統(tǒng)上運(yùn)行。JSP技術(shù)使用Java編程語言編寫類XML的tags和scriptlets，來封裝產(chǎn)生動態(tài)網(wǎng)頁的處理邏輯。網(wǎng)頁還能通過tags和scriptlets訪問存在于服務(wù)端的資源的應(yīng)用邏輯。JSP將網(wǎng)頁邏輯與網(wǎng)頁設(shè)計和顯示分離，支持可重用的基于組件的設(shè)計，使基于Web的應(yīng)用程序的開發(fā)變得迅速和容易。Web服務(wù)器在遇到訪問JSP網(wǎng)頁的請求時，首先執(zhí)行其中的程序段，然后將執(zhí)行結(jié)果連同JSP文件中的HTML代碼一起返回給客戶。插入的Java程序段可以操作數(shù)據(jù)庫、重新定向網(wǎng)頁等，以實(shí)現(xiàn)建立動態(tài)網(wǎng)頁所需要的功能。JSP與JavaServlet一樣，是在服務(wù)器端執(zhí)行的，通常返回該客戶端的就是一個HTML文本，因此客戶端只要有瀏覽器就能瀏覽。JSP的1.0規(guī)范的最后版本是1999年9月推出的，12月又推出了1.1規(guī)范。目前較新的是JSP1.2規(guī)范，JSP2.0規(guī)范的征求意見稿也已出臺。JSP頁面由HTML代碼和嵌入其中的Java代碼所組成。服務(wù)器在頁面被客戶端請求以后對這些Java代碼進(jìn)行處理，然后將生成的HTML頁面返回給客戶端的瀏覽器。JavaServlet是JSP的技術(shù)基礎(chǔ)，而且大型的Web應(yīng)用程序的開發(fā)需要JavaServlet和JSP配合才能完成。JSP具備了Java技術(shù)的簡單易用，完全的面向?qū)ο?，具有平臺無關(guān)性且安全可靠，主要面向因特網(wǎng)的所有特點(diǎn)。

\o"返回頁首"\o"返回頁首"JSP動態(tài)網(wǎng)站開發(fā)技術(shù)早期的動態(tài)網(wǎng)站開發(fā)技術(shù)使用的是CGI－BIN接口。開發(fā)人員編寫與接口相關(guān)的單獨(dú)的程序和基于Web的應(yīng)用程序，后者通過Web服務(wù)器來調(diào)用前者。這種開發(fā)技術(shù)存在著嚴(yán)重的擴(kuò)展性問題——每一個新的CGI程序要求在服務(wù)器上新增一個進(jìn)程。如果多個用戶并發(fā)地訪問該程序，這些進(jìn)程將耗盡該Web服務(wù)器所有的可用資源，直至其崩潰。為克服這一弊端，微軟公司提出了ActiveServerPages(ASP)技術(shù)，該技術(shù)利用“插件”和API簡化了Web應(yīng)用程序的開發(fā)。ASP與CGI相比，其優(yōu)點(diǎn)是可以包含HTML標(biāo)簽，可以直接存取數(shù)據(jù)庫及使用無限擴(kuò)充的ActiveX控件，因此在程序編制上更富有靈活性。但該技術(shù)基本上是局限于微軟的操作系統(tǒng)平臺之上，主要工作環(huán)境是微軟的IIS應(yīng)用程序結(jié)構(gòu)，所以ASP技術(shù)不能很容易地實(shí)現(xiàn)跨平臺的Web服務(wù)器程序開發(fā)。HypertextPreprocessor（超文本預(yù)處理器），即PHP動態(tài)網(wǎng)站開發(fā)技術(shù)與ASP相似，也是一種嵌入HTML文檔的服務(wù)器端腳本語言。其語法大部分與C、Java、Perl等語言相似，并形成了自己的獨(dú)有風(fēng)格，利用該語言Web程序員可以快速地開發(fā)出動態(tài)網(wǎng)頁。PHP在大多數(shù)Unix平臺、GUN/Linux和微軟Windows平臺上均可以運(yùn)行。PHP的優(yōu)點(diǎn)主要有：安裝方便，學(xué)習(xí)過程簡單；數(shù)據(jù)庫連接方便，兼容性強(qiáng)；擴(kuò)展性強(qiáng)；可以進(jìn)行面向?qū)ο缶幊痰取５玃HP也存在一些弱點(diǎn)，主要是PHP是一種解釋型語言，不支持多線程結(jié)構(gòu)，支持平臺和連接的數(shù)據(jù)庫都有限，特別是在支持的標(biāo)準(zhǔn)方面存在先天不足，對于某些電子商務(wù)應(yīng)用來說，PHP是不適合的。還有一些技術(shù)，如JavaServlets技術(shù)，利用該技術(shù)可以很容易地用Java語言編寫交互式的服務(wù)器端代碼。一個JavaServlets就是一個基于Java技術(shù)的運(yùn)行在服務(wù)器端的程序（與Applet不同，后者運(yùn)行在瀏覽器端）。開發(fā)人員編寫這樣的JavaServlets，以接收來自Web瀏覽器的HTTP請求，動態(tài)地生成響應(yīng)（可能需要查詢數(shù)據(jù)庫來完成這種請求），然后發(fā)送包含HTML或XML文檔的響應(yīng)到瀏覽器。這種技術(shù)對于普通的頁面設(shè)計者來說要輕易地掌握是很困難的。采用這種方法，整個網(wǎng)頁必須都在JavaServlets中制作。如果開發(fā)人員或者Web管理人員想要調(diào)整頁面顯示，就不得不編輯并重新編譯該JavaServlets。

太陽微系統(tǒng)公司(SunMicrosystemsInc.)在Web服務(wù)器、應(yīng)用服務(wù)器、交易系統(tǒng)以及開發(fā)工具供應(yīng)商間廣泛支持與合作下，整合并平衡了已經(jīng)存在的對Java編程環(huán)境（例如JavaServlets和JavaBeans）進(jìn)行支持的技術(shù)和工具后產(chǎn)生了一種新的、開發(fā)基于Web應(yīng)用程序的方法——JavaServerPages技術(shù)（JSP）。這種動態(tài)網(wǎng)站開發(fā)技術(shù)主要有以下一些特點(diǎn)：能夠在任何Web或應(yīng)用程序服務(wù)器上運(yùn)行；

分離了應(yīng)用程序的邏輯和頁面顯示；

能夠進(jìn)行快速的開發(fā)和測試；

簡化了開發(fā)基于Web的交互式應(yīng)用程序的過程。JSP的技術(shù)方法

為了快速方便地進(jìn)行動態(tài)網(wǎng)站的開發(fā)，JSP在以下幾個方面做了改進(jìn)，使其成為快速建立跨平臺的動態(tài)網(wǎng)站的首選方案。

1.將內(nèi)容的生成和顯示進(jìn)行分離

用JSP技術(shù)，Web頁面開發(fā)人員可以使用HTML或者XML標(biāo)識來設(shè)計和格式化最終頁面，并使用JSP標(biāo)識或者小腳本來生成頁面上的動態(tài)內(nèi)容（內(nèi)容是根據(jù)請求變化的，例如請求賬戶信息或者特定的一瓶酒的價格等）。生成內(nèi)容的邏輯被封裝在標(biāo)識和JavaBeans組件中，并且捆綁在腳本中，所有的腳本在服務(wù)器端運(yùn)行。由于核心邏輯被封裝在標(biāo)識和JavaBeans中，所以Web管理人員和頁面設(shè)計者，能夠編輯和使用JSP頁面，而不影響內(nèi)容的生成。

在服務(wù)器端，J