Computers, Programming
Hais ntawm Java khoom qauv: ib tug paub daws teeb chav kawm ntawv, ib tug interface
Lub tswv yim tseem ceeb ntawm cov abstract chav kawm ntawv yog muaj nyob rau hauv cov nram no theses: tej zaum yuav tsum tau tsis muaj ua noj ua haus cov chav kawm ntawv, thiab nyob rau hauv "ntub" daim ntawv. Tej teb yuav tsis tau ncaj qha mus siv (instantiate).
Yuav ua li cas yog ib tug paub daws teeb hauv chav kawm ntawv nyob rau hauv Java
Xav txog lwm cov piv txwv. Muaj yog ib tug Java paub daws teeb hauv chav kawm ntawv Calendar nyob rau hauv Java.util pob. Nws tsis siv ib lub daim ntawv qhia hnub, uas yog siv, piv txwv li, nyob rau hauv Western thiab Eastern Europe, Tuam Tshoj, North Kauslim, Thaib teb, thiab lwm yam Tiam sis nws tsis muaj ntau pab nta, xws li muab ib tug ob peb hnub mus rau ib tug tej hnub: .. Cov zog yog yuav tsum tau rau tej daim ntawv qhia hnub ntawm kev siv. Nws yog tsis yooj yim sua los tsim ib daim ntawv luam ntawm cov paub daws teeb hauv chav kawm ntawv.
Abstract chav kawm ntawv, paub daws teeb Java txoj kev
Xav tias koj xav kom tsim ntau yam graphical hais, e.g., geometric duab: .. Ib tug vajvoog, duab plaub, lub hnub qub, thiab lwm yam Thiab muaj ib lub taub ntim uas thim lawv. Txhua tivthaiv ntawm cov tsos sib txawv, li ntawd, tus uas tsim nyog txoj kev (txawm yog hais tias nws yog hu ua xim) yog siv txawv. Txawm li cas los, txhua tivthaiv muaj ntau yam zoo sib xws: .. Tus naj npawb yuav tsum tau muaj nyob rau hauv lub thawv yuav muaj ib cov xim yuav tsum tau pom thiab tsis pom, thiab lwm yam Nyob rau hauv lwm yam lus, koj yuav tsum tau tsim ib tug niam txiv hauv chav kawm ntawv rau tag nrho cov ntawm cov nuj nqis, qhov twg txhua tivthaiv yuav tau lub general zog.
Yog hais tias ib tug hauv chav kawm ntawv muaj paub daws teeb txoj kev, cov chav kawm ntawv yog paub daws teeb. Ua ntej lo lus chav kawm ntawv muab cov lo lus tseem ceeb paub daws teeb, lub npe ntawm cov qauv - ib yam nkaus thiab. Tom qab lub npe ntawm xws li ib tug qauv no yog tsim nyog los muab tso rau ib tug semicolon. Nyob rau hauv Java, ib tug paub daws teeb hauv chav kawm ntawv yuav tsis ua ntawv luam. Yog hais tias peb xav kom ban lawv creation, txawm yog hais tias muaj yog tsis muaj paub daws teeb txoj kev ntawm lub chav kawm ntawv, cov chav kawm ntawv muaj peev xwm yuav tshaj tawm hais tias abstract. Tab sis yog hais tias tus hauv chav kawm ntawv muaj tsawg kawg yog ib tug paub daws teeb method, cov chav kawm ntawv yuav tsum paub daws teeb. Nws yog tsis yooj yim sua rau hauv chav kawm ntawv yog thiab paub daws teeb yog, thiab thaum kawg, thiab txoj kev ib yam nkaus thiab. Cov kev tsis tau paub daws teeb, lwm yam, zoo li qub, cov haiv neeg. Yuav kom subclass ib tug yuav tshaj tawm uas tsis yog-paub daws teeb thiab instantiate, lawv yuav tsum siv tag nrho paub daws teeb txoj kev niam txiv. Cov chav kawm ntawv nws tus kheej muaj peev xwm siv nws paub daws teeb txoj kev.
Piv txwv li:
- paub daws teeb hauv chav kawm ntawv AClass {
- pej xeem paub daws teeb tsis muaj dabtsis txoj kev (rau cov menyuam a) ;
- }
- chav kawm ntawv BClass extends AClass {
- pej xeem tsis muaj dabtsis txoj kev (rau cov menyuam a) {
- // lub cev
- }
Pub cov tsiaj ntawv xws li paub daws teeb hauv chav kawm ntawv. Lawv yuav xa mus rau ib tug uas tsis yog-paub daws teeb tus me nyuam ntawm cov hoob kawm ntawd los yog yuav thov.
Interfaces nyob rau hauv Java - ib tug lwm txoj rau ntau yam qub txeeg qub teg
Nyob rau hauv Java, muaj yog tsis muaj ntau yam qub txeeg qub teg, vim hais tias ces muaj tej yam teeb meem. Ib tug hauv chav kawm ntawv yuav tsis tau txais los ntawm ob peb cov chav kawm ntawv. Tab sis nws yuav siv ntau yam interfaces.
Java interfaces thiab paub daws teeb kawm ntawv - lub tswv yim no zoo sib xws, tab sis tsis zoo tib yam. Lub interface yuav tshaj tawm hais tias raws li pej xeem, ces nws yog muaj nyob rau tag nrho cov, los yog koj yuav tso tawm tus modifier pej xeem, ces cov interface yog muaj tsuas yog nyob rau hauv nws pob. Abstract lo lus tseem ceeb yog tsis yuav tsum tau, vim hais tias cov interface thiab thiaj li yog paub daws teeb, tab sis koj muaj peev xwm qhia kom meej.
Ib tug interface tshaj tawm
Nws pib nrog ib tug header, thiab tej zaum yuav thawj mus rau tus lo lus tseem ceeb rau pej xeem, ces - lo lus interface. Ces yuav muaj ib lo lus ncua thiab hloov interfaces, los ntawm uas pub no. Nws yog tsis tau tso cai rau rov hais dua, thiab nws yog tsis yooj yim sua kom tsim ib tug cyclic piv ntawm cov qub txeeg qub teg kev sib raug zoo. Ces los txog rau interface lub cev, ntawm nyob rau hauv curly kev zawm hniav. Nyob rau hauv lub cev ntawm lub interface ntsiab yog tshaj tawm hais tias: Teb constants thiab paub daws teeb txoj kev. Tag nrho cov teb yog pej xeem zaum kawg zoo li qub - tag nrho ntawm cov modifiers yog tsis tsim nyog. Tag nrho cov kev pom tau hais tias yuav pej xeem paub daws teeb - cov modifiers kuj yuav teev. Tam sim no, txaus yog hais txog qhov sib txawv ntawm ib tug paub daws teeb hauv chav kawm ntawv los ntawm lub Java interface.
- pej xeem interface AI extends B, C, D {
- // lub cev
- }
Yuav kom tshaj tawm ib tug hauv chav kawm ntawv interface txais, yuav tau siv cov lo lus tseem ceeb implements:
- chav kawm ntawv AClass siv BI, CI, DI {}
Uas yog, yog tias tom qab cov chav kawm ntawv tshaj tawm siv qee interface lub npe, nws cov qeb implements. Qub txeeg qub teg ntawm no hauv chav kawm ntawv tau txais nws cov ntsiab, li ntawd, lawv kuj muag nws.
Ntau yam ntawm ib tug interface hom no kuj tso cai. Lawv yuav xa mus rau ib hom ntawm cov chav kawm ntawv uas implements no interface, los yog thov. Tej tsiaj muaj tag nrho cov ntsiab ntawm lub Nruas chav kawm ntawv, vim hais tias cov khoom yog generated los ntawm cov chav kawm ntawv, thiab lawv, nyob rau hauv lem, neeg los ntawm lub Nruas chav kawm ntawv.
Nyob rau hauv no tsab xov xwm, peb tau sib tham txog ib co ntsiab ntawm Java khoom qauv - paub daws teeb kev kawm ntawv, paub daws teeb txoj kev interface.
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