计算机系 Java EE 外文翻译 外文文献 英文文献Word下载.docx

计算机系 Java EE 外文翻译 外文文献 英文文献Word下载.docx

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（5）AnoverviewofhowtobuildFlexapplicationsusingevents,states,MXMLcomponents,andmodules.

（6）AnintroductiontodevelopingaFlexapplicationwithreal-timeserverdatapush.

（7）Howtoboostproductivitydevelopingdata-intensiveapplicationsusingtheDataManagementserviceinLiveCycleDataServices.

（8）AnoverviewofmodeldrivendevelopmentusingFlashBuilderandLiveCycleDataServicestogenerateclientandserver-sidecode.

（9）HowtodeployaFlexapplicationonaportalserver.

（10）BesuretoalsowatchthevideoIntroductiontoFlex4andJavaintegration.

（11）Tolearnmoreaboutthetechnologiesusedtobuildtheseapplications,readThetechnologiesforbuildingFlexandJavaapplicationsarticle.

Client/serverarchitecture

FlexandJavaapplicationsuseamulti-tierarchitecturewherethepresentationtieristheFlexapplication,thebusinessorapplicationtieristheJavaEEserverandcode,andthedatatieristhedatabase.Youcanwritetheback-endcodejustasyounormallywouldforaJavaapplication,modelingyourobjects,definingyourdatabase,usinganobject-relationalframeworksuchasHibernateorEJB3,andwritingthebusinesslogictoqueryandmanipulatetheseobjects.ThebusinesstiermustbeexposedforaccessviaHTTPfromtheFlexapplicationandwillbeusedtomovethedatabetweenthepresentationanddatatiers.

TypicalHTMLapplicationsconsistofmultiplepagesandasausernavigatesbetweenthem,theapplicationdatamustbepassedalongsotheapplicationitself（thecollectionofpagesandfunctionalityitconsistsof）canmaintainstate.Incontrast,Flexapplications,bynature,arestateful.AFlexapplicationisembeddedinasingleHTMLpagethattheuserdoesnotleaveandisrenderedbyFlashPlayer.TheFlexapplicationcandynamicallychangeviewsandsendandretrievedataasynchronouslytotheserverinthebackground,updatingbutneverleavingthesingleapplicationinterface（seeFigure1）（similartothefunctionalityprovidedbytheXMLHttpRequestAPIwithJavaScript.）

Figure1.Theclient/serverarchitecture.

Client/servercommunication

Flexapplicationscancommunicatewithback-endserversusingeitherdirectsocketconnectionsormorecommonly,throughHTTP.TheFlexframeworkhasthreeremoteprocedurecallAPIsthatcommunicatewithaserveroverHTTP:

HTTPService,WebService,andRemoteObject.AllthreewrapFlashPlayer'

sHTTPconnectivity,whichinturn,usesthebrowser'

sHTTPlibrary.Flexapplicationscannotconnectdirectlytoaremotedatabase.

YouuseHTTPServicetomakeHTTPrequeststoJSPorXMLfiles,toRESTfulwebservices,ortootherserverfilesthatreturntextoverHTTP.YouspecifytheendpointURL,listenerfunctions（thecallbackfunctionstobeinvokedwhentheHTTPServicerequestreturnsasuccessfulorunsuccessfulresponse）,andadatatypeforthereturneddata（whattypeofdatastructureitshouldbetranslatedintooncereceivedintheFlexapplication）.YoucanspecifythedatatobehandledasrawtextandassignedtoaStringvariableorconvertedtoXML,E4X,orplainoldActionScriptobjects.IfyougetbackJSON,youcanusetheAdobeFlexcorelibpackageofclassestodeserializetheJSONobjectsintoActionScriptobjects.TomakecallstoSOAPbasedwebservices,youcanusetheHTTPServiceAPIorthemorespecializedWebServiceAPI,whichautomaticallyhandlestheserializationanddeserializationofSOAPformattedtexttoActionScriptdatatypesandviceversa.

ThethirdoptionformakingremoteprocedurecallsistousetheRemoteObjectAPI.ItmakesaFlashRemotingrequesttoamethodofaserver-sideJavaclassthatreturnsbinaryActionMessageFormatoverHTTP.Whenpossible,useFlashRemotingwhosebinarydatatransferformatenablesapplicationstoloaddataupto10timesfasterthanwiththemoreverbose,text-basedformatssuchasXML,JSON,orSOAP（seeFigure2）.ToseeacomparisonofAMFtoothertext-basedserializationtechnologies,seeJamesWard'

sCensusRIABenchmarkapplication.

Figure2.MethodsforconnectingFlexandJava.

FlashRemoting

FlashRemotingisacombinationofclientandserver-sidefunctionalitythattogetherprovidesacall-and-responsemodelforaccessingserver-sideobjectsfromFlashPlatformapplicationsasiftheywerelocalobjects.ItprovidestransparentdatatransferbetweenActionScriptandserver-sidedatatypes,handlingtheserializationintoActionMessageFormat（AMF）,deserialization,anddatamarshalingbetweentheclientandtheserver.

FlashRemotingusesclient-sidefunctionalitybuiltintoFlashPlayerandserver-sidefunctionalitythatisbuiltintosomeservers（likeColdFusionandZend）butmustbeinstalledonotherservers（asBlazeDSorLiveCycleDataServicesonJavaEEservers,WebORBorFluorineFXon.NETservers,theZendframeworkoramfphponPHPservers,andmore）.SeethetechnologiesforbuildingFlexandJavaapplicationsarticleformoredetailsaboutBlazeDSandLiveCycleDataServices.

BlazeDSandLiveCycleDataServicesuseamessage-basedframeworktosenddatabackandforthbetweentheclientandserver.TheyprovideRemoting,Proxying,andMessagingservices,andforLiveCycle,anadditionalDataManagementservice.TheFlexapplicationsendsarequesttotheserverandtherequestisroutedtoanendpointontheserver.Fromtheendpoint,therequestispassedtotheMessageBroker,theBlazeDSandLiveCycleDataServicesenginethathandlesalltherequestsandroutesthemthroughachainofJavaobjectstothedestination,theJavaclasswiththemethodtoinvoke（seeFigure3）.

Figure3.FlashRemotingarchitecture.

AMF

AMFisabinaryformatusedtoserializeActionScriptobjectsandfacilitatedataexchangebetweenFlashPlatformapplicationsandremoteservicesovertheInternet.Adobepublishesthisprotocol;

thelatestisAMF3SpecificationforActionScript3.YoucanfindtableslistingthedatatypemappingswhenconvertingfromActionScripttoJavaandJavatoActionScripthere.

Forcustomorstronglytypedobjects,publicproperties（includingthosedefinedwithgetandsetmethods）areserializedandsentfromtheFlexapplicationtotheserverorfromtheservertotheFlexapplicationaspropertiesofageneral0bject.Toenablemappingbetweenthecorrespondingclientandserver-sideobjects,youusethesamepropertynamesintheJavaandActionScriptclassesandthenintheActionScriptclass,youusethe[RemoteClass]metadatatagtocreateanActionScriptobjectthatmapsdirectlytotheJavaobject.

HereisanexampleEmployeeActionScriptclassthatmapstoaserver-sideEmployeeJavaDTOlocatedintheservicespackageontheserver.

packagevalueobjects.Employee{[Bindable][RemoteClass（alias="

services.Employee"

）]publicclassEmployee{publicvarid:

int;

publicvarfirstName:

String;

publicvarlastName:

（...）}}

InstallingBlazeDSorLiveCycleDataServices

TouseFlashRemotingwithBlazeDSorLiveCycleDataServices,youneedtoinstallandconfigurethenecessaryserver-sidefiles.ForBlazeDS,youcandownloaditasaWARfilewhichyoudeployasawebapplicationorasaturnkeysolution.Theturnkeydownloadcontainsaready-to-useversionofTomcatinwhichthetheBlazeDSWARfilehasalreadybeendeployedandconfiguredalongwithavarietyofsampleapplications.Similarly,forLiveCycleDataServices,theinstallerletsyouchoosetoinstallLiveCyclewithanintegratedTomcatserverorasaLiveCycleDataServiceswebapplication.

Ineitherscenarioawebapplicationcalledblazedsorlcds（usuallyappendedbyaversionnumber）iscreated.YoucanmodifyandbuildoutthisapplicationwithyourJavacode,ormoretypically,youcancopytheJARfilesandconfigurationfilestheblazedsorlcdswebapplicationcontainsandaddthemtoanexistingJavawebapplicationontheserver（seeFigure4）.

Figure4.TherequiredBlazeDSorLiveCycleDataServicesfiles.

Modifyingweb.xml

Ifcopyingthefilestoadifferentwebapplication,youalsoneedtomodifytheweb.xmlfiletodefineasessionlistenerforHttpFlexSessionandaservletmappingforMessageBroker,whichhandlesalltherequestsandpassesthemofftothecorrectserver-sideJavaendpoints.Youcancopyandpastethesefromtheoriginalblazedsorlcdswebapplicationweb.xmlfile.

<

!

--HttpFlexSessionattributeandbindinglistenersupport-->

<

listener>

listener-class>

flex.messaging.HttpFlexSession<

/listener-class>

/listener>

--MessageBrokerServlet-->

servlet>

servlet-name>

MessageBrokerServlet<

/servlet-name>

display-name>

/display-name>

servlet-class>

flex.messaging.MessageBrokerServlet<

/servlet-class>

init-param>

param-name>

services.configuration.file<

/param-name>

param-value>

/WEB-INF/flex/services-config.xml<

/param-value>

/init-param>

load-on-startup>

1<

/load-on-startup>

/servlet>

servlet-mapping>

url-pattern>

/messagebroker/*<

/url-pattern>

/servlet-mapping>

Optionally,youmayalsowanttocopyandpaste（anduncomment）themappingforRDSDispatchServlet,which