Migrating a JSF-Based Web Application from Spring 3 to Java EE 7 and CDI
•
6 j'aime•3,304 vues
This talk is a detailed case study about the migration of a JSF-based web application from Spring 3 to Java EE 7 and CDI. It is presented at the JavaOne 2014 conference. At first sight this didn’t seem to be too difficult. Both technologies are based on similar concepts and provide similar mechanisms for dependency injection (DI). So migrating pure annotation based bean wiring from Spring to CDI was obvious and straight forward. But the deeper we looked into the source code the more Spring specific code we found with no direct and easy mapping in neither of JEE7, EJB3 or CDI available. Some of the problems and challenges we were confronted with were: - How to migrate XML based bean wirings? - How to migrate FactoryBeans? - How to migrate AspectJ based AOP proxies? - How to implement Spring profiles for environment based wiring? - How to implement custom bean scopes? - How to implement custom Spring XML schema notations and wiring? - How to migrate code that is built against Spring APIs? - How to migrate unit test based on Spring Test? To answer these questions the talk will present the patterns and strategies used to map, transform and migrate the different concepts from Spring 3 to JEE7with CDI. The talk will discuss the changes and implications of the migration on the system’s architecture.
Recommandé
Recommandé
Contenu connexe
Tendances
Tendances (20)
Similaire à Migrating a JSF-Based Web Application from Spring 3 to Java EE 7 and CDI
Similaire à Migrating a JSF-Based Web Application from Spring 3 to Java EE 7 and CDI (20)
Plus de Mario-Leander Reimer
Plus de Mario-Leander Reimer (20)
Dernier
Dernier (20)
Migrating a JSF-Based Web Application from Spring 3 to Java EE 7 and CDI
- 1. Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI Mario-Leander Reimer mario-leander.reimer@qaware.de QAware
- 2. 2| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer This talkwill … Give a brief overview of the system’s architecture Try to explain the rationale behind the migration Outline differences and similarities between both technologies Show patternsandstrategiesused during the migration to translate the different concepts Discuss implications on the system’s architecture Highlight problems, challenges and lessons learned
- 3. 3| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer A<<Application Cluster>> AIR LoaderMechanicA<<System>> AIR CentralA<<Subsystem>> MaintenanceA<<System>> AIR RepositoryI<<Subsystem>> Apache SolrA<<Client>> AIR ClientI<<Subsystem>> .NET WPFA<<Subsystem>> Solr ExtensionsA<<Subsystem>> DefectsA<<Subsystem>> Flat RatesA<<Subsystem>> Service BulletinsServiceTechnicianA<<Ext. System>> 3rd Party ApplicationA<<Subsystem>> AIR Fork DLLA<<Subsystem>> AIR Call DLLLaunchI<<Subsystem>> Spring FrameworkI<<Subsystem>> JEE 5A<<System>> AIR ControlI<<Subsystem>> JenkinsA<<Subsystem>> DocumentsA<<Subsystem>> VehiclesA<<Subsystem>> MeasuresBackend Databasesand SystemsA<<Subsystem>> Repair OverviewA<<Subsystem>> MasterdataA<<Subsystem>> JSF Web UIA<<Subsystem>> REST APIIndependentWorkshopA<<Client>> BrowserSearch andDisplayA<<Ext. System>> 3rd Party iOS AppA<<Subsystem>> AIR iOS LibA<<Subsystem>> DefectsA<<Subsystem>> Flat RatesA<<Subsystem>> Service BulletinsI<<Subsystem>> Spring FrameworkA<<Subsystem>> DocumentsA<<Subsystem>> PartsA<<Subsystem>> WS ClientsA<<Subsystem>> File StorageA<<Subsystem>> Solr AccessA<<Subsystem>> ProtocollA<<Subsystem>> WatchlistA<<Subsystem>> MasterdataA<<Subsystem>> RetrofitsAIR DBDocumentStorageA<<Ext. System>> AIR BusI<<Ext. System>> Backend SystemsQueryA<<Subsystem>> VehiclesExecuteLoad400 GBSolr IndexA<<Subsystem>> Maintenance
- 4. 4| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Whywouldyouwanttomigratea stableandrunningsystem? The shortanswer: IT governance. The longanswer: JEE nowprovidesthesame functionalityandisa standard Easy andcostefficientmigrationtofutureJEE versions Lowercostsforweb infrastructureandapplicationoperations Easy applicationmaintenanceby*-shorecompanies Noadditional vendorsupportrequired, noadditional costs
- 5. 5| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer
- 6. 6| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Annotation basedwiringofcomponentsusingconstructorinjection
- 7. 7| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer UsageofcustomSpring annotationsformoreexpressiveness
- 8. 8| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer XML basedwiringofcomponentsforSpring specificbeansandmorecomplexcomponents
- 9. 9| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer FactoryBeanstobuildbeaninstanceswithregularJava code
- 10. 10| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Usageofpropertyplaceholdersupporttoinjectconfigurationvalues
- 11. 11| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Implementation ofAspectJbasedproxiesforcrosscuttingconcerns
- 12. 12| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer ProgrammaticbeanlookupusingtheRegistry patternandtheApplicationContext
- 13. 13| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer UsageofSpring beanprofilesforenvironmentspecificbeanconfigurations
- 14. 14| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Spring XML namespacesforsyntacticsugar
- 15. 15| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Unit andmoduletestsheavilyuseandrelyon theSpring Testing framework
- 16. 16| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Wewerefacedwithmorequestionsthanwehadanswersfor How to migrate basic annotation based bean wiring? How to migrate XML based bean wiring and factory beans? How to migrate Spring property placeholder support? How to migrate AspectJ based AOP proxies? How to migrate programmatic bean lookups? How to migrate Spring bean profiles? How to migrate custom Spring XML namespaces? How to migrate code that is built against Spring APIs? How to migrate unit test based on Spring Test?
- 17. 17| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer
- 18. 18| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer
- 19. 19| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer All new Java EE 7 Maven Coordinates
- 20. 20| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Individual Mavenmodulesasmainunitofmigration ReplaceSpring annotationsandwiringswithCDI equivalent ReplaceXML contextdefinitionswithbeans.xml Optional: adjustcomponentstobenefitfromCDI Find and/orbuildsubstitutesforSpring specificfeatures Adjustunitandintegrationtests
- 21. 21| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Basic Spring toCDI annotationmigrationisstraightforward, withsubtledifferences Caution: Spring andCDI havea different defaultscope! CDI usesclientproxiesper default(exceptfor@Dependent), in Spring youhavetodo thisexplicitly. This mightinfluenceyourwiringstyle. Becarefulwithfinal. Spring Annotation CDI Annotation @Component(„myBean“) @Named(„myBean“) @Scope(„singleton“) @ApplicationScoped @Scope(„prototype“) @Dependent @Scope(„request“) @RequestScoped @Scope(„session“) @SessionScoped @Autowired @Inject Default Default
- 22. 22| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Bothtechnologiessupport@Qualifiertodistinguishvariousimplementations Tip: do not use@Namedtoqualifyyourcomponentsin CDI, use custom@Qualifierannotationsinstead.
- 23. 23| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer @Stereotype istheCDI equivalenttocustom@Componentannotations Tip: check the@Target annotationoftheCDI stereotype, and includeMETHODso itcanbeappliedto@Producesmethods.
- 24. 24| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Migrate*-components.xml tobeans.xml Tip: useCDI 1.1 bean-discovery-mode=„annotated“ astheequivalenttoSpring‘scomponentscan.
- 25. 25| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer XML based bean wiring as well as factory beans are migrated to Producer methods -Factory beanscanalso usedependencyinjection -Support forlifecycle -Constructorinjection -Nestedfactorybean
- 26. 26| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer XML based bean wiring as well as factory beans are migrated to Producer methods
- 27. 27| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer ThereisnodirectequivalenttoSpring‘s@Value(„${some.property}“) annotation
- 28. 28| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Property injectionsupportforCDI usingtheDeltaSpikeConfigurationMechanism Tip: havea lookat Apache DeltaSpikebeforeyoustartbuilding yourowncustomCDI extensionsformissingfeatures.
- 29. 29| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Migrating Spring AOP using @Interceptor and @InterceptorBindingannotations Activate aspectsandautoproxy relevant beans Pointcutforall publicmethodsin classesannotatedwith@Service Pointcutforall publicmethodsin classesannotatedwith@Repository
- 30. 30| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Migrating Spring AOP using @Interceptor and @InterceptorBindingannotations
- 31. 31| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer The CDI way for programmatic bean lookup improved our code enormously BeanManageristhe~ equivalenttoApplicationContext MigratedApplicationContextAwarestaticregistryclasstousetheBeanManagerinstead Advice: don‘tuseBeanManagerdirectly.It‘stoolowlevel. Don‘tusea staticregistryeither. Gruesometestability! Tip: ifstaticaccesstocontextualreferencesisreallyrequired, usetheDeltaSpikeBeanProviderimplementation.
- 32. 32| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Are Alternatives theequivalenttoSpring‘sbeandefinitionprofiles? Almost. Problem: Alternatives needtobeactivatedin thebean.xml Not suitableforenvironmentspecific, dynamicactivation. Usea CDI extensiontovetoannotatedtype ifprofileisnot active. Alternative: UsetheDeltaSpikeProjectStagemechanism.
- 33. 33| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer The migrationofourcustomSpring XML namespacesseemedtobea challenge Create instanceoftype FiniteStateMachinewithgivenID asbeanname Enumtype definitions Create transitioninstancewithgivenproperties Bean lookupbynameforactioninstancetoexecute
- 34. 34| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Programmaticapproach: combineBuilderpatternwitha producermethod Usedfornamedaction beanlookup
- 35. 35| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Improvedapproach: usea CDI extensiontoreadXML filesandcreateFSM beans Createsinstances, usestheBuilderfromfirstapproach
- 36. 36| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer DirectusageofsimplifiedJMS 2.0 API insteadofSpring‘sJmsTemplate Sending Receiving
- 37. 37| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer ReplacingSpring‘sTesting Framework was painfulanda lotofwork SpringJUnit4ClassRunnerMockitoJUnitRunner This workreallypaidof Simplifiedunittestswithbetterisolation decreasedexecutiontime Different approachesandtestrunnersforCDI testsavailable: JglueCDI-Unit: @RunWith(CdiRunner.class) DeltaSpikeTest-Control: @RunWith(CdiTestRunner.class) Arquillian: @RunWith(Arquillian.class) Testing a CDI enabledJAR in isolationiscomplexandlaborious(orjust didn‘twork)
- 38. 38| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer Andtherewas a lotmorecodetomigrate MigratedSpring taskexecutionandschedulingfuntionalityto@AsyncmethodsorJEE7 ManagedExecutorService The JPA persistencecodemigrationwentsmoothly Migratedpersistence.xml fromJPA 1.0 to2.1 Simple JPA unittestsusingDBUnitfortestdatasetup The JSF web layermigrationwas quitetedious Homogenizeannotationusage: replacedFacesbeanannotationswithCDI equivalent(e.g. @ManagedBean@Named) RemovedRegistry basedlookupofservicefacadeinstances Migratedandsimplifiedunittests, thisalso improvedtestquality
- 39. 39| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer 28 daysand300K LOC later…
- 40. 40| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer 28 daysand300K LOC later… … wehadtheAIR Central web applicationfullymigratedandrunningon Glassfishv4. Migration effortswereordersofmagnitudelowerthaninitiallyestimatedandanticipated! The standaloneAIR Loaderapplicationswerenexttomigrate: usingCDI fromJava SE, evenmorecomplexSpring XML namespace, comprehensiveusageofSpring JDBC.
- 41. 41| JavaOne2014 | Migrating a JSF-based web application from Spring 3 to Java EE 7 and CDI| M.-Leander Reimer LessonsLearnedandResumé JEE7 andCDI havedefinitelycaughtupon Spring Therewas noSpring featurethatcouldnot bemigrated Someconvenienceisstill missing, but CDI provideslightweightandeasy touseextensionmechanisms, thereisgrowingsupportfromtheOpen Source community. Questionandrethinkestablishedpatternsandbestpractices More carefulwhenusingandbindingtoa specificframework
Notes de l'éditeur
- Detailed case study about the technology migration of a current project for a major German car manufacturer Ask audience: who uses Spring / who uses JEE? Disclaimer: No prejudice! No bashing on either technology. This talk is purely about technology.
- Some Facts: - Rollout since last year, by the end of this year world wide - 17250 concurrent sessions / h - Spring Framework with some JEE5 Glassfish v2 and JDK6 400K LOC, 200K Tests, 100K Generated, 100K Handwritten Good quality, good performance, good acceptance
- Blueprint approval required for all used open source libraries Benefit from latest bug fixes and technology improvements More efficient and faster development mit einem lachenden und einem weinenden Auge == with mixed feelings
- Our first reaction: no way this is possible in adequate time. This is like taking out and replacing the spine! But we were curious, it should definitely be possible.
- Usually only @Component is enough. You can also give your beans a name. @Scope support: singleton and prototype. Session and request also supported in combination with a webapp. Careful with injection scoped proxies. Visibility guarantees, strong expression of dependencies
- More expressiveness: Custom Component annotations, like @Service or @Repository Custom Qualifiers for type safety
- Good old logging aspect example. measure execution times, echo parameters, start and end of invocation
- Service Locator pattern also called Registry
- An example: Spring DSL for a FiniteStateMachine. Other examples: other Spring namespaces, Mule ESB, Camel Looks fancy, but it is not really hard to implement: XSD, NamespaceHandler and BeanDefinition parser.
- Absolutely essential. Test basic wiring of components using mocks. Every Maven module has ist own integration test to test module wiring in isolation.
- You get the point. The longer you develop, the more you use technology to it‘s full potential. This is our migration agenda for the next 30 minutes.
- New technology and programming wouldn‘t be so much fun if it was boring and straight forward. It is those technically challanging projects that make live as a developer interesting and worthwhile. It was time to learn something new. Still unsure about the effort it would take.
- JEE7 Migration: Areas of Interests a lot of congruence Spring – CDI Everything else CDI Extensions (Deltaspike + Custom) Common Annotations Interceptors for AOP JPA Persistence JMS for Asnyc Stuff Enterprise Beans for Services (maybe) Concurrency for Replacement of Executors.* Servlets -> 3.0 with CDI Web Fragements New JSF + EL JAX-RS / JAX-WS
- All New Java EE 7 Maven Coordinates + 2 few more Definitely less than all the required Spring dependencies + transitive tail deps
- Every business component is usually composed of API, Core and UI module. Sometimes loader module. We have 100+ different Maven modules, all following the same pattern. But obviously with subtle differences in Spring API usage and wiring.
- No equivalent for @Scope(„globalSession“) in CDI No equivalent for @ConversationScoped in Spring Subtle differences: Default scope in Spring is Singleton, in CDI it is @Dependent In CDI you will get a client proxy, in Spring usually not. JSR-330: no @Required or @Lazy
- Characterize your components using stereotypes. @Component can be anything. Usually you also define the lifecycle using @Scope here also.
- A producer method acts as a source of objects to be injected, where: - the objects to be injected are not required to be instances of beans, - the concrete type of the objects to be injected may vary at runtime or - the objects require some custom initialization that is not performed by the bean constructor For example, producer methods let us: - expose a JPA entity as a bean, - expose any JDK class as a bean, - define multiple beans, with different scopes or initialization, for the same implementation class, or - vary the implementation of a bean type at runtime.
- A producer method acts as a source of objects to be injected, where: - the objects to be injected are not required to be instances of beans, - the concrete type of the objects to be injected may vary at runtime or - the objects require some custom initialization that is not performed by the bean constructor For example, producer methods let us: - expose a JPA entity as a bean, - expose any JDK class as a bean, - define multiple beans, with different scopes or initialization, for the same implementation class, or - vary the implementation of a bean type at runtime.
- No equivalent to Spring‘s @Value annotation in JSR-330.
- Tip: before you start building a CDI extension or missing feature, have a look at Apache DeltaSpike
- AOP as the swiss army nife for cross-cutting concerns: - Logging, security, transactions, …
- AOP as the swiss army nife for cross-cutting concerns: - Logging, security, transactions, …
- My most favourite CDI feature: programmtic bean lookup. The simplicity is just awesome. Provides all you need to get hold of desired instances. Good testability.
- Bean definition profiles: enhancements in Spring Framework 3.1 Don‘t forget to activate the stereotype in beans.xml Naive approach: Alternatives and stereotype activation. Better: use DeltaSpike ProjectStages. Optimal: Build a custom CDI extension.
- Main advantage: it‘s code. It‘s readable and testable. Slight disadvantage: does get quite long for big FSMs. Also you need to hand code it.
- Idea: reuse the existing XML definitions for the FSMs. Parse these configurations and build bean instances. Again, the Apache DeltaSpike project saved us a lot of work. 3h and 290 LOC, comments included. https://github.com/rmannibucau/cdi-light-config
- We often used Spring tests with injection and mocks. Migrated towards Mockito mocks and injection. No problem.
- Nothing to be scared of anymore. CDI from Java SE DeltaSpike Core
- Nothing to be scared of anymore. CDI from Java SE DeltaSpike Core
- http://realworldpatterns.com/ - Real world Java EE Patterns. Rethinking Best Practices. You live and learn: man lernt nie aus! Basics are easy to understand and implement. And mostly sufficient. Basics: this also applies to building Spring based applications.