Imiyalelo yokwenza isicelo se Java esilula kwi Unix
Izinto Ezinkulu NgeJava
I-Java yinkqubo yokuzimela eyimfuneko yokuphuhlisa i-software. Iqulethwe ngolwimi lwenkqubo, iinkqubo zokuncedisa kunye nexesha lokuhamba. Inkqubo yeJava inokuphuhliswa kwikhompyutha enye kwaye isebenze nayiphi na enye ikhomputha ngexesha elifanelekileyo lokusingqongileyo. Ngokuqhelekileyo, iiprogram zeJava ezidlulileyo ziyakwazi ukuqhuba kwiindawo zokuhlala zintsha. I-Java ityebile ngokwaneleyo ukuba nezicelo ezinzima kakhulu zingabhalwa ngaphandle kokuxhomekeka kwenkqubo yokusebenza. Oku kuthiwa yi-100% yeJava.
Ngokuphuhliswa kwe-intanethi i-Java ifumaneke ekuthandweni, kuba xa uhlela kwiWebhu, awukho indlela yokwazi ukuba yeyiphi indlela umsebenzisi angayiyo. Ngeelwimi yeprogram yeJava, ungasebenzisa ithuba "ukubhala kanye, ugijime naphina" iparadigm. Oku kuthetha ukuba xa uqokelela inkqubo yakho yeJava, awuyi kudala imiyalelo kwelinye iqela elithile. Kunoko, udala ikhowudi ye-Java ye-byte, oko kukuthi, imiyalelo ye-Java Virtual Machine (Java VM). Kubasebenzisi , akukhathazeki ukuba yiyiphi iplani abayisebenzisayo- Windows, Unix , MacOS, okanye isiphequluli se-Intanethi-nje nje ngokuba ine-Java VM, iyaqonda loo khowudi ye-byte.
Iintlobo zeeNkqubo zeJava
- "i-applet" yenkqubo yeJava eyenzelwe ukuba ifakwe kwiwebhsayithi lewebhu.
- "i-servlet" yenkqubo yeJava eyenzelwe ukuba isebenze kumncedisi.
Kule meko mibini iprogram yeJava ayikwazi ukuqhutywa ngaphandle kweenkonzo ze-Web browser kwi-applet okanye kwi-Web server kwi-servlet.
- "I-Java application" yenkqubo yeJava ekwazi ukuqhutywa yedwa.
Imiyalelo elandelayo kukuba ulungise inkqubo ye-Java usebenzisa ikhompyutha esekelwe kwi Unix.
Uluhlu lokuHlola
Elula kakhulu, ufuna kuphela izinto ezimbini zokubhala inkqubo yeJava:
(1) I-Java 2 Platform, Standard Edition (J2SE), eyayibizwa ngokuba yiJava Development Kit (JDK).
Landa uguqulelo olutsha lwe Linux. Qinisekisa ukukhuphela i-SDK, kungekhona i-JRE (i-JRE ifakiwe kwi-SDK / J2SE).
(2) Umhleli wombhalo
Phantse nayiphi na umhleli oyifumana kwiiplatifti ezisekelwe kwi-Unix ziya kwenza (umzekelo, i-Vi, i-Emac, i-Pico). Siza kusebenzisa uPio njengomzekelo.
Inyathelo 1. Yakha ifayile yomthombo weJava.
Ifayile yomthombo iqulethe umbhalo obhaliweyo kulwimi lweprogram yeJava. Ungasebenzisa nayiphi na umhleli wombhalo ukudala nokuhlela ifayile yomthombo.
Unokukhetha ezimbini:
* Unokugcina ifayile yeFatCalories.java (ekupheleni kweli nqaku) kwikhompyuter yakho. Le ndlela ingakugcina uthayibhile. Emva koko, unako ukuya ngqo kwisinyathelo 2.
* Okanye, ungayilandela imiyalelo emide:
(1) Khupha igobolondo (ngezinye izihlandlo ebizwa ngokuba yi-terminal) window.
Xa uqala ukukhawuleza, i-directory yakho yangoku iya kuba yincwadi yakho yasekhaya. Ungatshintsha i-directory yakho yangoku kwirekhodi yakho yasekhaya nganoma naliphi ixesha ngokuthayipha i-cd kwi-prompt (ngokuqhelekileyo "%%") kwaye ucinezela ukubuya.
Iifayile zeJava ozidalileyo mazigcinwe kwirejista ehlukile. Unokwenza ulawulo ngokusebenzisa i- mkdir yomyalelo. Umzekelo, ukudala i-java yerejista kwirekhodi yakho yasekhaya, uqale utshintshe i-directory yakho yangoku kwirekhodi lakho lasekhaya ngokufaka umyalelo olandelayo:
% cd
Emva koko, ungangena umyalelo olandelayo:
% mkdir java
Ukutshintsha i-directory yakho yangoku kule khowudi entsha, uya kungena: % cd java
Ngoku ungaqala ukudala ifayile yakho yomthombo.
(2) Qala umhleli we-Pico ngokuthayipha i-pico ngexesha lokukhawuleza nokuchukumisa ukubuya. Ukuba inkqubo iphendula ngomyalezo we-pico: umyalelo awunakufumaneka , ngoko iPio ayinakufumaneka. Qhagamshelana nomlawuli wakho wenkqubo ngolwazi olungaphezulu, okanye sebenzisa enye umhleli.
Xa uqala i-Pico, iya kubonisa ibhokisi elitsha, elingenanto. Le yindawo apho uya kufaka ikhowudi yakho.
(3) Thayipha ikhowudi eboniswe ekupheleni kweli nqaku (phantsi kwe "Sample Java Programme") kwi-buffer engenanto. Thayipha yonke into njengoko ibonisiwe. I-Java iqulunqa kunye notoliki yinkcazo yecala.
(4) Gcina ikhowudi ngokuthayipha i-Ctrl-O. Xa ubona igama lefayile libhalela :, udidi lweFatCalories.java, olulandelayo ngoluhlu apho ufuna ukuba ifayili ihambe khona. Ukuba unqwenela ukugcina iFatCalories.java kwi-directory / ekhaya / smith / java, uze uthayiphe
/home/smith/java/FatCalories.java kunye neenkcukacha zokubuya .
Sebenzisa i-Ctrl-X ukuphuma kwi-Pico.
Inyathelo 2. Qulunqa ifayile yomthombo.
I-Java iqhagamshela, i-javac, ithatha iifayile yakho yomthombo kwaye iguqulela itekisi yayo kwimigaqo yokuba iMashini yangaphandle yeJava (Java VM) iyaqonda. Umqambi ubeka le miyalelo kwifayili yekhodi ye-byte.
Ngoku, velisa enye iwolubha iwindi. Ukuqulunqa ifayile yakho yomthombo, utshintshe i-directory yakho yangoku kwirejista apho ifayile yakho ifumaneka khona. Umzekelo, ukuba isixhobo sakho somthombo ngu / home / smith / java, uthayipha umyalelo olandelayo kwi-prompt uze ucindezele kwakhona.
% cd / ikhaya / smith / java
Ukuba ufaka i-pwd ngexesha elikhawulezayo, kufuneka ubone i-directory yangoku, ekukulo mzekelo utshintshile kwi / home / smith / java.
Ukuba ufaka i-ls ngexesha elikhawulezayo, kufuneka ubone ifayile yakho: FatCalories.java.
Ngoku unako ukuqokelela. Ngexesha elikhawulezayo, thayipha umyalelo olandelayo uze ucinezela Buyela: javac FatCalories.java
Ukuba ubona lo myalezo wephutha:
javac: Ulawulo alufumanekanga
ngoko Unix akakwazi ukufumana i-Java compiler, javac.
Nantsi enye indlela yokuxelela u-Unix apho ufumane khona i-javac. Masithi ufake iJava 2 Platform (J2SE) kwi /usr/java/jdk1.4. Kwixesha elikhawulezayo, thayipha umyalelo olandelayo uze ucinezela Ukubuya:
/usr/java/jdk1.4/javac FatCalories.java
I-compiler ngoku ivelise ifayile yekhowudi ye-byte ye-Java: FatCalories.class.
Kwixesha elikhawulezayo, faka uhlobo ls ukuqinisekisa ukuba ifayile entsha ikhona.
Isinyathelo 3. Qalisa iNkqubo
I-Java VM iphunyezwa ngumtoliki weJava obizwa ngokuthi nguJava. Esi sitshixo sithatha ifayile yakho yekhowudi ye-byte kwaye yenza imiyalelo ngokuyiguqulela kwimigaqo ekhompyutheni yakho ingayiqonda.
Kulo lawulo olufanayo, faka kwi-prompt:
java FatCalories
Xa uqhuba inkqubo kufuneka ufake amanani amabini xa iqhosha lomgca womyalelo omnyama livela. Inkqubo kufuneka ibhale loo manani amabini kunye neepesenti ezibalwe yinkqubo.
Xa ufumana umyalezo wephutha:
Ngaphandle kwenkcazo "enkulu" java.lang.NoClassDefFoundError: FatCalories
Kuthetha ukuba: i-java ayikwazi ukufumana ifayile yakho yeefayile ye-byte, iFatCalories.class.
Into enokuyenza: Enye yeendawo i-java izama ukufumana ifayile yakho yekhowudi ye-byte yakho yerekhodi yangoku. Umzekelo, ukuba ifayile yakho yekhowudi ye-byte ikhona / ekhaya / smith / java, kufuneka utshintshe i-directory yakho yangoku kulo ngokukuthayipha umyalelo olandelayo kwi-prompt kunye ne-hit Return:
cd / home / smith / java
Ukuba ufaka i-pwd ngexesha elikhawulezayo, kufuneka ubone / ikhaya / smith / java. Ukuba ufaka i-ls ngexesha elikhawulezayo, kufuneka ubone amafayili akho eFatCalories.java kunye neFatCalories.class. Ngoku ungena kwi-java FatCalories kwakhona.
Ukuba unesxaki, unokufuneka utshintshe i-CLASSPATH yakho. Ukuze ubone ukuba oku kuyimfuneko, zama "ukucima" i-classpath ngomyalelo olandelayo:
ukusetha CLASSPATH
Ngoku ungena kwi-java FatCalories kwakhona. Ukuba le nkqubo isebenza ngoku, uza kufuneka utshintshe i-CLASSPATH yakho.