Video: Peb puas tuaj yeem muab cov niam txiv cov khoom rau cov khoom me me hauv Java?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Niam txiv thiab Me nyuam cov chav kawm muaj tib cov ntaub ntawv tus tswv cuab hauv Java . Cov ntaub ntawv sib txawv ntawm cov Niam txiv chav kawm muaj peev xwm tuav nws khoom siv raws li nws tus menyuam yam khoom siv. Cov ntaub ntawv tuav lub tus menyuam chav kawm khoom siv yuav tsis tuaj yeem nkag mus rau cov tswv cuab (functions lossis variables) ntawm cov tus menyuam chav kawm.
Hais txog qhov no, puas muaj peev xwm muab ib qho khoom ntawm ib hom me nyuam rau qhov sib txawv ntawm hom niam txiv piv txwv?
Tsis yog-tab sis a khoom ntawm niam txiv hom tau ua muab rau qhov sib txawv ntawm hom menyuam.
Peb puas tuaj yeem muab cov khoom superclass rau subclass? Tsis yog. Nws ua rau xoom qhov tso cai rau qhov ntawd. Qhov laj thawj yog vim li cas subclass feem ntau txhais tus cwj pwm ntxiv. Yog koj muab tau a superclass khoom rau a subclass siv, koj yuav khiav mus rau hauv cov teeb meem ntawm runtime thaum koj sim nkag mus rau cov tub kawm uas tsis muaj nyob.
Tom qab ntawd, lo lus nug yog, cov menyuam kawm ntawv puas tuaj yeem tsim cov khoom ntawm niam txiv chav kawm?
Hauv cov ntsiab lus yooj yim, Yam khoom ntawm niam txiv chav kawm tau tuav khoom ntawm cov menyuam kawm ntawv . Rov qab ua tau tsis muaj tseeb.
Ib yam khoom puas tuaj yeem faib lwm yam khoom?
Ua tau ib khoom ntawm a subclass nkag mus tiv thaiv teb ntawm lwm yam khoom ntawm lwm subclass ? Muaj qee zaus, txawm li cas los xij, thaum koj xav txwv ib txoj hauv kev subclass tsuas yog los yog, tsawg dua, tso cai subclass txoj kev nkag mus rau ib qho chaw superclass. Nyob rau hauv tas li ntawd, koj tshaj tawm ib chav kawm feature raws li kev tiv thaiv.
Pom zoo:
Peb puas tuaj yeem muab padding hauv feem pua?
Qhov feem pua : Qhov loj ntawm padding yog txheeb ze rau qhov dav ntawm lub ntsiab lus cheeb tsam (piv txwv li qhov dav sab hauv, thiab tsis suav nrog, padding, ciam teb thiab cov npoo ntawm lub caij). Yog li, yog tias koj #wrapper yog 940px wide, 5% padding = 0.05 × 940pixels = 47 pixels
Subclass puas tuaj yeem hu rau niam txiv tus tsim qauv?
Tsis muaj subclass tsis tuaj yeem tau txais cov neeg tsim khoom ntawm nws cov superclass. Constructors yog cov tswv cuab tshwj xeeb ntawm cov chav kawm uas lawv tsis tau txais los ntawm subclass. Constructors yog siv los muab lub xeev siv tau rau ib yam khoom ntawm creation
Puas txhais tau tias yog kev sib raug zoo ntawm cov khoom ntawm ib yam khoom thiab lub peev xwm ntawm tus neeg sawv cev uas muab cov lus qhia rau kev siv cov khoom?
Kev them nyiaj yog kev sib raug zoo ntawm cov khoom ntawm ib yam khoom thiab lub peev xwm ntawm tus neeg sawv cev uas txiav txim siab seb qhov khoom siv tau li cas
Peb puas tuaj yeem tsim cov khoom dynamic hauv C# thiab DynamicObject yog dab tsi?
Hauv C#, koj qhia meej hom khoom alate-bound li dynamic. Koj tuaj yeem tsim koj tus kheej hom uas tau txais DynamicObjectclass. Tom qab ntawd koj tuaj yeem hla cov tswv cuab ntawm cov chav kawm DynamicObject kom muab sijhawm ua haujlwm dynamicfunctionality
Peb puas tuaj yeem siv cov lus npaj rau xaiv cov lus nug hauv Java?
Yuav siv cov lus npaj li cas rau xaiv cov lus nug hauv Java nrog MySQL? Tam sim no koj tuaj yeem tso saib tag nrho cov ntaub ntawv ntawm lub rooj siv Java PreparedStatement. Koj yuav tsum siv txoj kev executeQuery()