课堂考勤管理系统设计及实现英文翻译.docx

课堂考勤管理系统设计及实现英文翻译.docx

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课堂考勤管理系统设计及实现英文翻译

课堂考勤管理系统设计及实现英文翻译

英文翻译

年级:

2002

学号:

20020051

姓名:

苏宁博

专业:

计算机科学与技术指导老师:

陈帆

二零零六年六月

英文翻译第1页

ActiveServerPages&XHTML&XMLActiveServerPages

WhenyousurftheInternetandperuseaWebpagewithinteractivecontent,chancesarethatthepagewasdevelopedusingMicrosoftCorp.’sActiveServerPages（ASP）technologyor

SunMicrosystemsInc.’sJavaServerPages（JSP）technology.Forexample,aWeb

pagecontainingaweatheroutlooktypicallyoffersdynamicinformationbasedon

specificrequestsfromtheWebbrowser.Thegraphicalpresentationofthepagewon’t

change,regardlessofwhethertheuserrequestsafive-dayforecastforDenveror

Seattle,butaccurateweatherinformation-whichusuallygetspulledfroma

database-does.

ASPsandJSPsaretwoofthemostpopulartechnologiesforgeneratingthattypeofdynamiccontentforaWebpage.Theprimarydifferencebetweenthetwo

developmentmethodsisthatASPsgenerallyinteractwithaback-endenvironment

builtwithMicrosofttechnologies,whileJSPsliveinaJava-basedenvironment.

MicrosoftintroducedASPs,alongwithitsInternetInformationServer3.0,toallowdeveloperstocreateWebpagesthatcaninteractwithdatabasesandother

applications.

AnASPisaserver-sidescriptingenvironmentusedtocreatedynamic,interactiveWebpages.ItcontainsHTML,whichdefinesthepagelayout,fontsandgraphic

elements,andembeddedprogrammingcodethat’swritteninaMicrosoftscripting

language.

MostASPsarewrittenusingVisualBasicScriptorJavaScript,butscriptingenginesforlanguagessuchasPerlandPythonareavailablethroughthird-partyvendors.

WhenaWebbrowsermakesarequest,theembeddedscriptrunsandpullsupafile

withan.aspextensionfromtheWebserver,whichreturnsthenewresultstothe

browser.

英文翻译第2页

Asyoumightexpect,JavaServerPagesareSun’sJavaequivalentofMicrosoft’sASPs.JSPtechnologyisbuiltontopofservlets,aportableJavaprogramthat

providesserver-sideprocessing.

XHTML

ThedaysinwhichyoucouldlearnHTMLinashorttimeandcraftyourownWebpageusingatexteditorarenumbered.Onthebrightside,handlinganyWebsite

that’sbiggerthan10or20pagesisabouttogetaloteasier.

“ThebigwinisthatyounolongerhavetoforcedatastructuresinHTML.”saysStevenPemberton,chairmanoftheWorldWideWebConsortiums（W3C）HTML

WorkingGroup.

W3CworkswithbusinessesandgovernmentstocreateWebstandards.Butbrowsermakershistoricallyhaven’twaitedforW3Cspecificationsandhaveeither

implementedstandardsbeforethey’refullydefinedorimplementedthemincorrectly.

XHTMListheW3CsattempttoredrawlinesblurredbybrowsermakersHTMLwas

createdtobeastructurallanguage-nothingmore.Butbrowsermakersquicklybegan

pushingtheenvelope,addingpresentationcapabilities.Thatofteninvolved

nonstandardtagsortrickyshortcutssuchasusingtablestolayoutapage,which

couldslowpage-loadingtimesdrasticallyandcomplicateWebsitecontent

management.

IntheXHTMLspecification,thelanguageisonceagainonlystructural.Tagsareusedtomarkupheadings,paragraphs,lists,hypertextlinksandotherstructuralparts

ofthedocument.Stylesheets,ontheotherhand,handleissuesofpresentation:

fonts,

colorsandmargins.Theintentistosimplifysites,decreasedownloadtimesandmore

easilypresentthesamecontenttomultipletypesofdevices.

XHTMLworksbyseparatingcontentfromstyle.ContentcreatorscraftHTML;designerscreatestylesheets.ThissimplifiestheWebservers’job,sincesitevisitors

needtodownloadastylesheetonlyonce.Everysubsequentpagethatreferstothat

stylesheetdownloadsmuchmorequickly.Changingthelookofthesiteissimplified

becauseyouhavetochangeonlyafewstylesheets,notthousandsofHTMLpages.

英文翻译第3页

Webserverprocessingpowerissavedandlessmaterialistransmitted,sinceHTML

documentsarefreeoffonttagsandcolorspecifications.

AfutureversionofXHTMLwillintroducemodules.Manydevices,suchascell

phones,wouldneedonlyasubsetofXHTMLbecausemoduleswouldautomatically

filtertheXHTMLtoincludeonlywhatthedeviceneeds.

XHTMLwillultimatelyreplaceproprietaryWebfileformatssuchasPortable

DocumentFormatfilesandFlashandothermultimediaformats.Forexample,the

SynchronizedMultimediaIntegrationLanguage（SMILVersion1.0,

pronounced"smile"）allowsdesignerstodescribethetemporalbehaviorandlayoutof

aWebpageaswellasassociatehyperlinkswithobjects.AlongwiththeScalable

VectorGraphicsXMLstandard,designerscouldcreateanimationsorevenaugment

televisionfeedsusingXML.

DEFINITION

PutXMLandHTMLtogether,andyoucomeupwithXHTML,the

next-generationlanguagestandardfortheWeb.Thenewlanguageholdsthepromise

ofsimplifyinglifeforWebdevelopersbyclarifyingtheseparationbetweendata,

metadataandpresentationinformation.

XML

Peopleevenremotelyinvolvedwithintranetdevelopmentknowtheacronym

HTML.Thesamecan’tbesaidforXML-atleastnotyet.Forthosewhodon’tknow,

XMLstandsforExtensibleMarkupLanguage.Itdatesbackslightlymorethanayear,towhentheWorldWideWebConsortium（W3C）authorizedthecreationof

somethingcalledtheSGMLActivity.Nobodynoticed.XMLbrokethesurfacelast

Novemberwiththereleaseofthefirstlanguagespecification.Oneortwopeople

noticed.OnFebruary,MicrosoftCorp.andNetscapeCommunicationsCorp.

becamepubliclyinterestedinXML.Nowalotofpeoplearenoticing.Here’sanexplanationofwhyXMwasbuilt,whatitlookslikeandhowitcanbeputto

practicaluseonyourintranet.XMLisadrasticallysimplifiedsubsetoftheW3C''sStructuredGeneralMarkupLanguage（SGML）.Itprovideswhat’sneededtomake

intranetapplicationsrunsmarterandfaster.Onanintranet,XMLwillenabletwo

英文翻译第4页

capabilitiesnotablyabsentfromtoday’sWebtechnology.XMLwillmakeintranet

datamucheasiertomanage,becauseitwillbemuchricherandmoreself-describing.

Anditwillenablethedevelopmentofsmarter,fasterapplicationsbytransferringprocessingfromthegenerallyoverloadedservertotheoftenunderworkeddesktop

PC.WhyXML?

Webtechnologyisgreatbecauseit’seasy.Usersdon’tneedanytraininginhow

tomakeitgo,andinformationproviderscangetWeb-basedapplicationsrunningon

intranetsinnotime.ButWebtechnologyalsoisapain,becauseit’sstupidandslow.

It’sstupidbecauseitturnsapowerfuldesktopPCintoadumbbatchterminal.It’sslowbecausetogetanyworkdoneyouhavetosendabatchofinformationacross

thenetworktotheserverandthenbacktoyourdesktop.Theseproblemscanbe

solvedbydownloadingsomeoftheprocessingworktothefatPCsittinginfrontof

theuser.Thatway,theapplicationcodeonthedesktopcanrespondinstantlytoeachuserkeystrokeandcandoatleastpartofitsworkwithoutnetworkroundtripstotheserver.Oneofthekeystrategiesforsolvingthisproblemistheuseofsmarter

data.

IntranetsmostlyrunonHTML,whichdoesagreatjobofdisplayingdocument

andgraphics.Itcomeswithafixedsetoftagsandstructuresoptimizedforits

purpose.Thisisfine,butwhatifyouwantsomeindexinginformation,orwanttoidentifypartnumbers,orinventoriesordateofemploymentinyourintranetdata?

HTMLjustdoesn’tdothis,andwon’t.ThisiswhatXMLabout.Ratherthan

providingasetofpredefinedtags,XMLrequiresyoutodefineyourown.This

meanthedocumentsonyourintranetbecomericher,smarter,customizedtoyourneedsandreadyforusebyyourapplications.

Technicalhighlights

WhileXMLisactuallyasimplifiedversionofSGML,youdon’tneedto

understandSGMLtounderstandXML.

Thisisgood,becauseSGMLisincrediblygeneral,flexibleandhardto

understand.XMLtakesthemostcommonlyusedpartsofGMLandpackagesthem

inaneasy-to-understandway.

英文翻译第5页

WithXML,documentcomponentsaremarkedwithtagsandattributes,justasin

HTML.Youcaninventyourowntagsandattributesand,ifyouwant,sharethem

andcontroltheirusewithaformaldeclarationcalledaDocumentTypeDeclaration.What’smore,XMLisdesignedsoit’sincrediblyeasytowriteprogramstoreadand

extractinformationfromXMLfiles.Agoodprogrammercanwhipupsuchaprogram

inaday.

Inaddition,XMLhasbuilt-infacilitiesforreusingsharedinformationinmultiple

documentsormultipletimesinonedocument.Italsohandlesalltheworld’s

alphabets,basedontheUnicodestandard--youcanmixArabic,English,JapaneseandRussianwithnoproblems.

UnlikeHTML,XMLdoesn’thavebuilt-intagformatting,sincetherearenobuilt-intags.SotopresentXMLonscreenorpaper,youhavetowriteastylesheet.

Infact,XMLwouldn’tbeusefulifnotforthearrivalofCascadedStyleSheets（CSS）ontheWebtechnologyscene.

CSScontrolthedisplayofWebpagesbyusinganexternalstylesheetratherthan

built-intagbehaviors.

SinceXMLhasnobuilt-intagbehaviors,youhavetohavestylesheetsto

displayitatall.Butpagecreationismuchmoreflexileandsophisticated.

XMLalsorequiresanothernewWebtechnology--DynamicHTML.Oneof

XML’smainpurposesistoallowprogramsrunninginthebrowser（JavaorActiveX）

toaccessandmanipulatethedatayousendoveryourintranet.Upuntilrecently,withtheannouncementofDynamicHTMLfromMicrosoftandNetscape,browsers

didn’tmakethispossible.

WhileDynamicHTMLaddressestheproblem,thetwocompanies''versionsare

incompatible.Thegoodnewsisthattheyarenowworkingtogether