Bài giảng Lập trình mạng nâng cao: EJB: Stateful Session Bean - Nguyễn Xuân Vinh

Learning objectives of this chapter include: Define a Stateful Session Bean, list the characteristics of a Stateful Session Bean, write Stateful session bean programs, differentiate between Stateless and Stateful Session beans.
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Bài giảng Lập trình mạng nâng cao: EJB: Stateful Session Bean - Nguyễn Xuân Vinh TRƯỜNGĐẠIHỌCNÔNGLÂMTP.HCMGV:NGUYỄNXUÂNVINHMÔN:LẬPTRÌNHMẠNG2 KHOACÔNGNGHỆTHÔNGTIN EJB: Stateful Session Bean15/01/16 Presenter:NguyễnXuânVinh InformationTechnologyFaculty/XX NongLamUniversity1 TRƯỜNGĐẠIHỌCNÔNGLÂMTP.HCM KHOACÔNGNGHỆTHÔNGTIN SessionObjectivesGV:NGUYỄNXUÂNVINH  DefineaStatefulSessionBean  ListthecharacteristicsofaStatefulSessionBean.  WriteStatefulsessionbeanprograms.  DifferentiatebetweenStatelessandStatefulSessionbeans.MÔN:LẬPTRÌNHMẠNG215/01/16/XX2 TRƯỜNGĐẠIHỌCNÔNGLÂMTP.HCM KHOACÔNGNGHỆTHÔNGTIN ReviewofSession3(1of3)GV:NGUYỄNXUÂNVINH  Thebeanclass,theEJBobject,theremoteinterface,thehomeinterface,the homeobject,thedeploymentdescriptors,andthejarfilesconstitutethe enterprisebean.  Beanclasscontainstheimplementationofthebusinesslogicmethods.  EJBcontainerperformsimportantmanagementfunctionswhenitintercepts clientrequestssuchas: *TransactionlogicMÔN:LẬPTRÌNHMẠNG2 *Securitylogic *Beaninstancelogic  TheRemoteinterfaceduplicatesthemethodsexposedbythebeanclass.  ResponsibilitiesoftheEJBhomeobject: *CreatingEJBobjects *SearchingforexistingEJBObjects *RemovingEJBObjects15/01/16/XX3 TRƯỜNGĐẠIHỌCNÔNGLÂMTP.HCM KHOACÔNGNGHỆTHÔNGTIN ReviewofSession3(2of3)GV:NGUYỄNXUÂNVINH  Thedeploymentdescriptor:AfilethattellstheEJBserverabout theclasses,thehomeinterface,andtheremoteinterfacethatMÔN:LẬPTRÌNHMẠNG2 formthebean.  Thelifetimeofasessionbeanmaylasttillsuchtimeasthatofa clientsession.Itcouldbeaslongasawindowisopenoras longasanapplicationisopen.Sessionbeansdonot,therefore, surviveapplicationservercrashesormachinecrashes.  Threeclassesareessentialfordeployment:  HomeInterface15/01/16  RemoteInterface  Beanclass/XX4 TRƯỜNGĐẠIHỌCNÔNGLÂMTP.HCM KHOACÔNGNGHỆTHÔNGTIN ReviewofSession3(3of3)GV:NGUYỄNXUÂNVINH  Theejbjar.xmlfileisacompressedfilethatcontains thedeclarationsoftheenterprisebeanclass,theMÔN:LẬPTRÌNHMẠNG2 remoteinterfaceandthehomeinterface.  AnEJBclientcanbe: *AnordinaryJavaBean *AnotherEJB *AJSPPage *Aservlet *Anapplet15/01/16 *Astandaloneapplication/XX5 CharacteristicsofStatefulSession TRƯỜNGĐẠIHỌCNÔNGLÂMTP.HCM KHOACÔNGNGHỆTHÔNGTIN BeansGV:NGUYỄNXUÂNVINH  Conversionalstateoccurswhenaclientcallsamethodonabean.  Poolinghastobedonetoconserveresourcesandenhancesscalability.  Thecontainerswapsoutabeanandsavestheconversationalstateto theharddiskorotherstoragedevices.Thisprocessiscalled passivation.MÔN:LẬPTRÌNHMẠNG2  Whentheclientrequestsforamethod,thepassivatedconversational stateisreturnedtothebean.Thebeanisagainreadytomeetthe request.Thisprocessiscal ...