Java: InputStream. Muzifunsa mitsinje

Java, monga zinenero zambiri zamakono mapulogalamu, kuthandiza kukhazikitsa mitsinje deta athandizira. Mu Java InputStream ndi kalasi m'munsi kwa mamvekedwe mitsinje. kalasi ndi umboni, kuti, mu njira ya dongosolo sitingathe kulenga Mwachitsanzo za izo. Komabe, io phukusi waika wa maphunziro amene adzalandira ndi zokulitsa magwiridwe a InputStream. Ntchito kalasi code yanu, ayenera kunja kwa java.io.InputStream phukusi. Kenako, tikambirana za magwiridwe zofunika kuti apereke kalasi InputStream, ndi makalasi waukulu kukhazikitsa izo.

njira InputStream kalasi

Akuyendera phunziro mwatsatanetsatane njira InputStream kalasi, tiyenera ananena kuti zipangizo Closeable ndi AutoCloseable polumikizira. Chiyankhulo Closeable limatiuza kuti akamaliza ntchito ndi nthenda izo ayenera kutsekedwa. Izi zachitika ntchito njira pafupi (). Popeza ambiri a njira InputStream kalasi ngati kulakwitsa amapanga zosiyana mtundu IOException, ntchito zonse chofunika kuchita tiyese chipika ndi njira pafupi () potsiriza kupanga gulu kotero kuti ndale malinga ndi zotsatira za ntchito kuyesa thupi.

AutoCloseable mawonekedwe kwambiri kuchepetsa kuchuluka kwa yokonza code, chifukwa amalola pafupi () njira ntchito basi ndipo musati kuwonjezera malamulo anu potsiriza ndigwire. Ngati inu ntchito chiwiri kapena pambuyo buku la Java, InputStream ndi akhoza adzaikidwa mu otchedwa tiyese ndi chuma chimene ntchito zonse kutseka otaya Zimatero.

Taganizirani njira zoyambirira za InputStream kalasi:

• Int zilipo () - akubwerera Werengani chiwerengero cha mabayiti;
• Int kuwerenga () - akutenga mamvekedwe panopa gwero ndi akubwerera ndi inteja boma; ngati mabayiti onse kuwerenga, -1 amagwanso;
• Int kuwerenga (mamvekedwe [] gawo lotetezedwa) - Mbawerenga mabayiti zikupezeka anati gawo lotetezedwa mu mawonekedwe a mtundu mamvekedwe lomenyera (nambala ya mabayiti werengani gawo lotetezedwa wofanana kukula mwachindunji ndi kubwerera chiwerengero cha mabayiti werengani anapambana ndipo ngati mabayiti zonse zilipo kuwerenga, akubwerera -1);
• Int kuwerenga (mamvekedwe [] gawo lotetezedwa, Int kuchepetsa, Int chiwerengero cha mabayiti) - zimamuchulukira wa njira yapita, amachitanso chimodzimodzi, koma ndi chinaneneratu "kuchepetsa" malo ndipo limati mochuluka monga mu "chiwerengero cha mabayiti";
• yaitali Pitani (yaitali mamvekedwe achiyesa) - chiwerengero cha skips mabayiti ndi kubwerera chiwerengero cha anaphonya.

InputStream akuyendera makalasi angapo lakonzedwa kuti ntchito ndi zinthu zosiyanasiyana komanso mitundu deta. M'munsimu limasonyeza cholowa mtengo.

kuwerenga owona

Mamvekedwe mtsinje kuwerenga kafukufuku owona akuyendera kalasi FileInputStream. file kutsegula kuwerenga mabayiti, zokwanira kulenga Mwachitsanzo m'kalasimo, kudutsa kwa constructor wake wapamwamba dzina monga kukangana. Ngati file ndi kunditumiza ku dzina kulibe, icho adzaponya zosiyana za mtundu FileNotFoundException.

Mu nkhani ya bwino lotseguka wapamwamba, ntchito ndi iwo ikuchitika ntchito njira tafotokozazi, monga wolowa FileInputStream InputStream.

Kuwerenga mitundu wosazindikira deta

Mu chitsanzo pamwamba limafotokoza ntchito mfundo mamvekedwe, amene angathe kutanthauziridwa monga zizindikiro. Koma bwanji ngati tiyenera kuwerenga ndi inteja, fractional kapena mtengo Buliyani? Kuti muchite izi Java InputStream njira zina zambiri kalasi DataInputStream. kalasi ndi wrapper kwa InputStream, amene ankadutsa pa chilengedwe kuti mtsutso wa constructor. Mtundu uwu wa ulusi akuwerenga deta mu mawonekedwe bayinare.

DataInputStream komanso zipangizo za DataInput mawonekedwe ndi njira zake kuwerenga mitundu wosazindikira deta. Mmunsimu muli mndandanda wa njira izi.

maina njira zikuyendera - aliyense wa iwo lakonzedwa kuti ndiwerenge zina mtundu deta.

Buffered athandizira mtsinje

Buffered mtsinje deta kuwerenga kuzindikira BufferedInputStream kalasi mu Java. InputStream ndi wokutidwa ndi kalasi. kalasi limeneli likugwirizana ndi gawo lotetezedwa mtsinje, wakupatsani kuwerenga nthawi yomweyo imodzi koma mabayiti angapo. Izi zimathandiza kuti kwambiri kusintha ntchitoyo ntchito. BufferedInputStream mbeu InputStream ndi yozungulira ndipo motero analandira njira zonse zatchulidwa pamwambapa.

kalasi ali constructors awiri:

• BufferedInputStream (InputStream athandizira mtsinje);
• BufferedInputStream (InputStream athandizira mtsinje, Int gawo lotetezedwa kukula)

Siginecha opanga akhoza anamvetsa kuti poyamba amapereka kusakhulupirika gawo lotetezedwa kukula, ndi wachiwiri ndi zotheka kuti pamanja.

Pomaliza

Takambirana kuzindikira mfundo zikuluzikulu za InputStream. Ngati mukufuna kuti atembenuke ndi mabayiti analankhulanso ndi chingwe ku Java InputStream kuti chingwe (), mwatsoka, si lomwa, choncho adzakhala ndi kugwiritsa ntchito zipangizo zapadera, mwachitsanzo IOUtils kwa Apache Commons laibulale.