The java.lang.nullpointerexception ndi vuto la Java lomwe limachitika pomwe pulogalamu ya Java ikuyesera kugwiritsa ntchito china m'malo mwa chinthu.
RuntimeException ikuwonjezedwa ndi NullPointerException, yomwe ndi gulu la anthu onse.
NullPointerException imakwezedwa muzochitika zosiyanasiyana, monga mukamatchula njira yachinthu chopanda pake. Cholakwika ichi chidzachitikanso ngati chinthu sichinagwire ntchito ndipo muyesa kupeza kapena kusintha gawo la chinthucho.
Ngati muyesa kupeza utali wa gulu lopanda pake, kuchotserako kudzakwezedwanso.
M'nkhaniyi, tiwona momwe tingagwiritsire ntchito Null Pointer Exception ku Java.
Pamene java.lang.nullpointerexception ichitika?
Pamene kusintha kwa java komwe sikuloza ku chinthu chilichonse kumapezeka pazochitika zilizonse, java.lang.nullpointerexception imayamba.
Kupatula nthawi yothamanga java.lang.nullpointerexception Kupatula pa nthawi yothamanga ndi java.lang.nullpointinterexception. Mukatanthauzira zosinthika koma osazipereka ku chinthu mpaka mutayesa kuzigwiritsa ntchito, mupeza java nullpointerexception.
Mukutanthauza chinthu chomwe sichinakhalepo. Mu Java, null amatanthauza mtengo winawake. Nthawi zambiri amagwiritsidwa ntchito kusonyeza kuti kusinthaku sikunaperekedwe mtengo kapena sikunapatsidwe mtengo uliwonse.
Kuti mupewe NullPointerException, onetsetsani kuti zinthu zonse zakhazikitsidwa bwino musanagwiritse ntchito zosinthika.
Zotsatirazi ndi zina mwazomwe zimachitika pafupipafupi za NullPointerException:
- Kupeza pa katundu wa null chinthu
- Kugwiritsa ntchito null object kuitana njira
- Pa chinthu chachabechabe, pogwiritsa ntchito synchronized
- Kuponyera zachabechabe kuchokera ku njira yoponya mwapadera
- Zotsutsa zopanda pake zimaperekedwa ku njira.
- Kupeza chinthu cha null index (monga mndandanda)
- Pazida za jakisoni wodalira ngati Spring, izi sizolondola.
Chitsanzo cha java.lang.nullpointerexception
NullPointerException idzaponyedwa ngati mtundu wa Java wapangidwa womwe sukutanthauza chinthu ndipo umagwiritsidwa ntchito pochita zina.
Chitsanzo chotsatirachi chikuyesera kudziwa kutalika kwa chingwe chomwe chatsekedwa.
Kukonza java.lang.nullpointerexception
Konzani 1
Pezani mtundu wa java womwe umaponya java.lang kupatula. Ngati pulogalamuyo iponya NullPointerException, yang'anani kawiri kuti kusinthaku kumaperekedwa kumtengo kapena chinthu.
Java.lang.nullpointerexception idzachotsedwa ngati mtengo waperekedwa ku java variable.
Konzani 2
Gwiritsani ntchito ternary operator kuti mutchule mtengo wokhazikika musanagwiritse ntchito kusintha kwa java kuti muchitepo kanthu ngati java.lang.nullpointerexception imaponyedwa mu variable.
Mtengo wosinthika udzagwiritsidwa ntchito ngati uli nawo. Apo ayi, kuti mupewe java.lang.nullpointerexception, mtengo wokhazikika ungagwiritsidwe ntchito.
Konzani 3
Ngati simukutsimikiza kuti ndi kusintha kotani komwe kumayambitsa java.lang.nullpointerexception kapena ngati pali mwayi woponya java.lang.nullpointerexception, kapena ngati pali chiopsezo chotaya java.lang.nullpointerexception m'malo angapo; zimatenga nthawi kuti muwonjezere cheke ku code.
Kuti muthane ndi vutoli yonjezerani chipika chophatikizirapo.
Konzani 4
Ngati kusintha kwa java mu pulogalamuyi kuponya java.lang.nullpointerexception, chitani cheke musanagwiritse ntchito.
Tengani njira ina ngati kusintha kuli kopanda pake. Chotsatira cha java.nullpointerexception chidzachotsedwa.
Kutsiliza
M'nkhaniyi, tayang'ana pa Java NullPointerException.
Izi ndizowopsa zomwe zimawonekera nthawi zambiri tikamayembekezera. Chomwe chimayambitsa Null Pointer Exception ndi chinthu chopanda pake kapena null reference.
Tawona kale mayankho ogwira mtima kwambiri.
Siyani Mumakonda