Enterprise Java Beans – Koj puas tseem nco qab?
Taw qhia: Nyob rau cov tshooj no, Peb noj ib teg num rau lo lus teb ib co ntawm cov lus nug nug rau EJB. Enterprise Java beans siv nyob rau ntau tus neeg mob. Nws yuav kov lub lag luam logic (Zaum Noj Taum), kev paub cai (Taum Paus) thiab lus (MDB). Peb twb sim compiled tej thaj chaw tseemceeb hauv EJB thiab teb cov lus nug. Qhov no yog thawj koob rau EJB. Peb yuav luam tawm ib co series ntau nyob rau hnub tom ntej. Vam tias yuav pab koj heev.
1: EJB yog dab tsi?
Teb: Tus EJB muaj txhais tau tias yog ib qho kev pab cuam uas sau rau hauv daim ntawv thov kev pab thiab yuav siv cov EJB specifications.
2: Daim ntawv thov kev pab yog dab tsi?
Teb: Daim ntawv thov kev pab yuav raug txhais tau tias yog ib qho kev pab cuam uas muab ib cheeb tsam mus enterprise daim ntaub ntawv.
3: Vim li cas daim ntawv thov kev pab yuav nyiam heev rau txoj kev loj hlob enterprise daim ntawv thov?
Teb: Daim ntawv thov kev pab muab tag nrho tej kev txhawb nyiam mloog, ruaj, hav zoov. npaj ua daim ntawv thov enterprise. Li ntawd, cov enterprise daim ntawv thov kev pab yog yooj yim npaum li cas thaum uas daim ntawv thov kev pab yog siv rau kev siv.
4: Lub npe ob nrov thov nrov servers siv tam sim nowadays?
Teb: Weblogic thiab websphere daim ntawv thov kev pab.
5: Qhov twg yog ib daim ntawv thov kev pab mus dhia?
Teb: Daim ntawv thov kev pab yuav khiav ob remotely thiab rau lub tshuab rau nws tus kheej.
6: Qhov txawv ntawm daim ntawv thov kev pab thiab EJB pab?
Teb: Daim ntawv thov kev pab yuav muab txhawb nqa rau ib daim ntawv thov enterprise thiab EJB muab kev pab txhawb nqa tau enterprise xwb.
7: Dab tsi yog ib tug enterprise taum?
Teb: Taum Enterprise yeej tsim los encapsulate lub lag luam logic ntawm ib daim ntawv thov enterprise. Nws yog ib tug Java EE sab component thiab sau hauv EJB container.
8: Thaum koj siv enterprise pib?
Teb: Taum Enterprise taum yog siv rau ntau teev daim ntawv thov kev pab. Yog li yog ib daim ntawv thov enterprise yuav tsum tau muas, kev ntseeg siab, scalability etc. ces enterprise taum yog qhov zoo tshaj plaws.
9: Cov taum muaj cov taum EJB3.0?
Teb: Nyob rau hauv EJB3.0 muaj ntau hom enterprise taum
1) Qhib lub rooj zaum
2) Lus uas tau tsav taum
10: Dab tsi interfaces yog eliminated hauv EJB3.0?
Teb: Tej thaj chaw deb thiab tej thaj chaw deb ntawm EJB3.0 version.
11: Rau cov qauv EJB3.0 tau tsim?
Teb: EJB3.0 tau tsim raws li lub hom phiaj tiaj nras java object (POJ NIAM) qauv programming.
12: Dab tsi yog hu ua lag ua luam logic txheej nyob rau hauv EJB?
Teb: Qhib taum thiab hais-uas tau tsav ua ke constitute lub lag luam logic txheej txheem hauv EJB.
13: Li cas yog persistence txheej?
Teb: Qhov no yog tus txheej txheem lub luag hauj lwm rau persisting daim ntawv thov kev pab nyob rau hauv ib relational database. Kev muaj taum no siv nyob rau hauv no txheeb.
14: Dab tsi yog cov sab ntawm EJB2.x x qhia?
Teb: Tom qab no yog ib co sab ntawm EJB2.x x specification
ib) Tivthaiv tau kev siv interfaces los ntawm EJB framework pob. Ces cov components yog nruj nruj nreem.
b) EJB deployment descriptors yog txoj thiab yuam kev lawm.
c) Kev kuaj cov nyuaj yog ib qho nyuaj.
d) Persistence qauv no tsis zoo txhais hais tias.
15: Piav tej nta ntawm EJB3.0 qauv.
Teb: Tom qab no yog ib co tseem ceeb nkag tau rau hauv EJB3.00 qauv
ib) Qhov chaw muaj taum hloov los ntawm POJO.
b) Deployment Deployment piav txog tej ntaub ntawv yuav hloov los ntawm cov ntawv tshaj tawm
c) JPA siv rau persistence qauv
16: Yuav siv cov lusnotations uas siv los ntawm EJB3.00 specification?
Teb: Cov metadata raws li cov lus qhia uas siv los ntawm EJB3.00 specification.
17: Ua li cas koj thiaj txhais tau ib hoob kawm poJO li ib tug EJB tivthaiv?
Teb: Thaum uas siv ntau hom ntawv annotations ib POJO hoob kawm yuav raug txhais li ib tug EJB tivthaiv.
18: Yuav ua li cas yog hom taum taum EJB3.0?
Teb: Muaj ob hom taum taum ib) xibfwb thiab big) xeev.
19: Thaum koj siv lub xeev cov kev sib kho taum?
Teb: Lub xeev cov kev sib kho no yog siv thaum lub xeev conversational lub xeev yuav tsum tsis tswj.
20: Dab tsi yog cov components txhais hauv EJB2.x stateless qhib tau?
Teb: Muaj peb lub ntsiab sib txeeb
ib) EJB tiv thaiv kev cuam tshuam
b) EJB tsev interface
c) EJB tau hoob kawm
21: Dab tsi yog siv los qhia ib lub xeev cov kev sib kho taum?
Teb: @Stateless tau siv los txhais ib lub xeev noob taum.
22: Yog dab tsi yog lub npe ntawm daim ntawv tshaj tawm?
Teb: Cov ntawv tshaj tawm qhia rau lub thawv uas lub POJO yog qhib thiab tswj txoj sia lub neej thiab runtime semantics.
23: Dab tsi yog siv los qhia txog kev siv tej thaj chaw deb li cas?
Teb: Tus '@Remote' annotation siv los saib ib thaj chaw deb ntawm tej thaj chaw deb.
24: Thaum koj siv ib lub xeev muaj taum?
Teb: Lub xeev cov kev sib kho kom haum yog siv thaum lub xeev ntawm ib txoj kev ua lag ua luam yuav tsum khaws cia.
25: Dab tsi yog siv los qhia ib lub xeev cov kev sib kho taum?
Teb: Cov '@Stateful' annotation siv los qhia ib lub rooj zaum stateless tau.
26: Muaj peev xwm sib kho los yog kawg PoJO?
Teb: Qhov kev sib kho no yuav tsum yog ib tug concrete POJO.
27: Muaj peev xwm sib kho EJB subclass lwm qhib EJB?
Teb: Tsis yog, sib kho EJB tsis tau subclass lwm zaug EJB. Nws yuav tsuas sub hoob kawm ib POJO.
28: Vim li cas ib lus uas tau tsav yog siv?
Teb: Cov taum uas tau tsav cov taum asynchronous lus tsis pub dhau ib J2E raws li daim ntawv thov J2E.
29: Leej twg yog lub luag hauj lwm rau invoking lus uas tau tsav?
Teb: Lus uas tau tsav cov taum invoked los ntawm lub thawv. Lawv yeej tsis invoked los ntawm ib tug neeg tau los yog lwm taum.
30: Dab tsi annotation siv rau cov lus uas tau tsav?
Teb: Cov '@MessageDriven' annotation siv rau ib cov lus uas tau tsav tau.
31: Dab tsi yog lub npe ntawm qhov kev cuam tshuam los ntawm ib cov lus uas tau tsav tau?
Teb: Cov 'Messageener' interface yog DVR tau DVR tau tsav. Thiab muaj tsuas yog ib txoj kev txhais hauv nws hu ua 'onMessage'.
32: Lub npe ntawm cov cuab yeej siv rau cov lus uas tau tsav rau cov ntaub ntawv hais txog tus kheej?
Teb: Lub npe yog 'ActivationConfigproperty'. Nws muaj tag nrho cov ntaub ntawv hais txog.
33: Yog tej yam uas annotations rau hu rov qab methods?
Teb: Cov ntaub ntawv yuav siv los kos rov hu rau txoj kev uas yuav tsum tau txhaj koob tshuaj tivthaiv kabmob.
34: Yog txoj kev mus los cycle methods mandatory hauv EJB 3.0 specification?
Teb: Tsis yog, Kev siv lub neej cycle methods yog kev xaiv hauv EJB 3.0 specification. Tab sis lawv yog tus tswv num hauv EJB 2.x x qhia txawm tias koj tsis siv nws.
35: Piav lub neej los ntawm ib lub xeev zaug taum.
Teb: Tom qab no yog lub neej cycle theem ntawm lub xeev zaug xeev taum
ib) Tsim
b) Dependency injection
c) PostConstruct hu rov qab
d) Tshem
e) Predestruct hu rov qab
