Java: shaqeynta files - qoraal, akhris, tirtirka

Java waxay leedahay qalab badan oo la files shaqeeyo, maxaa yeelay, waxay u adeegaan sida bakhaar ah oo xogta barnaamijyada badan. Inta badan u helaan in ay soo gudbiso waxaa loo baahan yahay in Android Java ah. Dhammaan casharada la files ku yaal xirmo java.io ah, kaas oo sidoo kale lagu kaydin fasalada waayo, talooyin iyo wax soo saarka durdurraa ka shaqeeya shaqeeya. Si adag u hadlayay, Java la files shaqada dhacdaa ugu horrayn via byte iyo talooyin qof iyo wax soo saarka durdurrada. marka laga reebo haddii ay taasi waa File fasalka. ka oo ay bilaabaan.

File Class Java - la shaqeynta Files

class File si toos ah ula dhaqmo files iyo nidaamka file. Tusaale ahaan An of class this ugu horayn waxa loo isticmaalaa si ay u helaan ka sifooyinka file ah iyo maraan madaxda ee subdirectories. Waxaa la ma go'aamiyo hababka soo saarida iyo kaydinta xogta in file ah, laakiin la class this, waxaad ka heli kartaa macluumaad badan oo ku saabsan taariikhda file, waqti, rukhsadda helaan iyo jidka buugga. Dhab ahaantii, wax class File waa fasiraadda file ama tusaha ee Java.

In la abuuro tusaale ah File ah, iyadoo la isticmaalayo mid ka mid ah constructors ay: File (String Jid in folder, String filename).

Tixgeli farsamooyinka aasaasiga ah ee fasalka, jidaynayey si ay u helaan macluumaad ku saabsan file ama buugga:

• getName () - laabtay magaca file ah;
• ka jira () - laabtay boolean run ah, haddii faylka jira, ama been ah in kiiska ka soo horjeeda;
• isFile () - go'aaminaya haddii shayga loola jeedaa in file ah, soo laabtay qiimaha u dhiganta macquul ah;
• isDirectory () - laabtay run, haddii ay tahay gal ah;
• canWrite () - laabtay run, haddii file waa writable;
• canRead () - laabtay run, haddii file waa akhrin karo;
• setReadOnly () - dhigaysa file ka akhrisan-kaliya,
• dhererka () - laabtay size file in bytes ah;
• renameTo (Magaca faylka cusub) - renames file hadda si waafaqsan doodaha. Sooceliyaa run, haddii hawlgalka waa guul,
• tirtirto () - tirtirtaa faylka ama folder (haddii ay madhan tahay), taasoo muujinaysa in wacaha;
• liiska () - retrieves liiska magacyada wax lagu kaydin tusaha, sida isugu soo xigta (dabaqi karo oo kaliya in ay tusaha).

Sidaas darteed, iyada oo la isticmaalayo fasalka File ah waxaa lagu bixiyaa Java la files iyo fayl shaqo.

La shaqaynta files by fasalada FileInputStream iyo FileOutputStream

Horaantii aynu u sheegnay in ay fuliyeen inta badan taasi oo ka iyo wixii soo baxayey durdurrada ee Java la files shaqada. durdurrada byte for files soo bandhigay qaab fasalada FileInputStream iyo FileOutputStream. fasalada Kuwanu waa wax dhaxashee oo ka mid ah saldhig fasalada aan la taaban karin InputStream iyo OutputStream siday u kala horreeyaan, si hababka fasallo, kuwaas oo diyaar u ah la files ka shaqeeya.

marka hore ka fiirso FileInputStream ah. Xirmooyinka of class this hoos lagu soo bandhigay,

constructor The horreeya sida wax xuja ah ee Jidka faylka sida oo xarig ah, oo kii labaadna wuxuu ahaa - in qaab wakiil shay. Inkastoo constructor ugu horeysay ka badan inta badan waxaa loo isticmaalaa in kiiska labaad waxa suurto gal ah inaad wax ka barato sifooyinka file la heli karo in hababka fasalka File. Marka aad la abuuro tusaale ah ee fasalka FileInputStream furmay durdur talooyin ah reading faylka.

constructors FileOutputStream Class ayaa hoos lagu muujiyey:

Xaaladdu waa mid la mid ah FileInputStream ah, laakiin waxa ay sidoo kale qaadan kartaa qiimaha "append" macquul ah, taas oo, marka run muujinaysaa in xogta waxaa loo qoray in file bartilmaameedka lagu lifaaqayo doonaa jira, iyo haddii been ah - tegi maayo overwrite file ah, ie, xogta jir aan la badbaadin doonaa.

Bal aynu eegno tusaale isticmaalaya fasalo kuwan:

aqbasho durdur file1.txt FileInputStream The akhriya xogta laga byte file by byte ah by habka of akhrin (). u qoran si kasta oo byte waxa lagu kaydiyaa variable ah qaab abyoonaha. Dheeraad ah, in jidhka loop halka , variable taas waxaa loo maray sida wax xuja ah in ay qoraan hab tusaale ah FileOutputStream, kaas oo qoray byte ku helay file file2.txt. Dhamaadka labada durdurrada si qasab xiran by dhow habka.

Fasallada FileReader iyo FileWriter

Haddii aad xaqiiqa ah u ogaada in marka la files ka shaqeeya, waxa aad helaysaa in qoraalka ka qaban, waxa macno in ay isticmaalaan qof a halkii durdurrada byte. qulqulka Kuwani waxaa lagu soo bandhigay fasalada FileReader iyo FileWriter ee Java. La shaqaynta files isticmaalaya fasallo, kuwaas oo meel ku saabsan isku qaadataa sidii kiiska hore. fasalada Kuwan waxaa soo degay Reader iyo Writer siday u kala horreeyaan, oo qeexaya qaababka asaasiga ah ee xogta la gelin iyo wax soo saarka.

Samaynta fasalada FileReader iyo FileWriter waxaa lagu soo bandhigay hoos ku qoran:

Heshii, kala duwan ee kelmedo marka la barbar dhigo byte durdurro shiidaa ma jiro. line hoose waa in fasalo kuwan waxaa si gaar ah loogu talagalay in la characters shaqeeyaan koodh caalamiga, ma aan samayn karo durdurrada byte. Taasi waa habka ugu Java loo habeeyey in shaqada la files. Tusaale fasalada xogta la siiyo hoos ku qoran:

Sida aad arki karto, kala duwanaanshaha aan la arkay. Waa in la ogaadaa in inkastoo dabeecadda socodka, ka celinta hab akhriyo, iyo habka qortaa qaadataa qiimaha abyoonaha ah. Inkastoo saxiixa hab u qortaa ku lug leedahay aqbaliddoodii muran nooca INT laga diiwaan geliyay durdurka, oo kaliya hoose 16 gelinno, calaamadaha sida matalayay Java waa sidaas oo tirada jajabka.

gunaanad

Sidaas daraaddeed, waxaan ka wada hadalnay fasalada aasaasiga ah ee la files ee Java shaqeeya. Waxaa xusid mudan in haddii aad u socotaan si ay u horumariyaan software for Java Android, si ammaan ah oo aad u isticmaali kartaa qalab this.