Yuav ua li cas kom tau txais kev nkag los ntawm tus neeg siv hauv Java (nrog Duab)

2024 Tus sau: Gilbert Ryder | [email protected]. Kawg hloov kho: 2023-12-16 17:32

Thaum ua haujlwm hauv Java lossis lwm yam lus, koj yuav zoo li yuav tsum tau siv cov ntaub ntawv nkag los ntawm tus neeg siv. Java muab ntau txoj hauv kev sib txawv kom tau txais cov ntaub ntawv siv, tab sis feem ntau thiab kab tias yooj yim tshaj plaws los siv txoj hauv kev yog siv cov khoom Scanner.

Cov kauj ruam

Txoj Kev 1 ntawm 2: Yeeb Yaj Kiab

Kauj Ruam 1. Ntshuam chav Scanner

Koj tuaj yeem xaiv xaiv import

java.util. Scanner

chav kawm lossis tag nrho

java.util

pob. Txhawm rau ntshuam chav kawm lossis pob, ntxiv ib kab hauv qab no mus rau qhov pib ntawm koj tus lej:

ntshuam java.util. Scanner; // Qhov no yuav ntshuam tsuas yog Chav Kawm Scanner. ntshuam java.util.*; // Qhov no yuav ntshuam tag nrho cov pob java.util.

Kauj Ruam 2. Pib lub hom phiaj Scanner tshiab los ntawm kev hla

System.in ua

input kwj rau tus tsim.

System.in ua

yog tus txheej txheem nkag nkag uas twb tau qhib thiab npaj los muab cov ntaub ntawv nkag mus. Feem ntau cov kwj dej no sib haum rau cov keyboard nkag.

Scanner userInputScanner = Scanner tshiab (System.in);

Kauj Ruam 3. Nyeem ntau hom ntaub ntawv uas tus neeg siv nkag mus

Chav Kawm Scanner txhawb nqa kom tau txais cov txheej thaum ub xws li int, byte, luv, ntev ntxiv rau kom tau txais cov hlua.

• Nov yog qee txoj hauv kev uas muaj los ntawm Chav Kawm Scanner:

  • Nyeem ib byte -

    tom ntejByte ()

  • Nyeem luv luv -

    tom ntejShort ()

  • Nyeem ib int -

    tom ntej no ()

  • Nyeem ntev -

    tom ntejLong ()

  • Nyeem ib ntab -

    tom ntejFloat ()

  • Nyeem ob npaug -

    tom ntejDouble ()

  • Nyeem boolean -

    tom ntejBoolean ()

  • Nyeem kab tiav -

    tom ntejLine ()

  • Nyeem ib lo lus -

    tom ntej ()

• Nov yog qhov piv txwv ntawm txoj haujlwm uas siv cov txheej txheem sib txawv ntawm Chav Kawm Scanner kom tau txais ntau hom kev tawm tswv yim:

  ntshuam java.util. Scanner; pej xeem chav kawm ScannerExample {pej xeem zoo li qub void lub ntsiab (Txoj hlua args) {// Pib lub Scanner tshiab scanner userInputScanner = Scanner tshiab (System.in); // Xeem nextLine (); System.out.println ("\ n Koj lub npe hu li cas?"); Txoj hlua lub npe = userInputScanner.nextLine (); // Xeem nextInt (); System.out.print ("Koj muaj pes tsawg tus miv?"); int numberOfCats = userInputScanner.nextInt (); // Xeem nextDouble (); System.out.print ("Muaj nyiaj ntau npaum li cas hauv koj lub hnab nyiaj? $"); ob npaug nyiajInWallet = userInputScanner.nextDouble (); System.out.println ("\ n Nyob zoo" + npe + "! Koj muaj" + numberOfCats + (numberOfCats> 1? "Miv": "miv") + "thiab $" + moneyInWallet + "hauv koj lub hnab nyiaj. / N"); }}
  

Txoj Kev 2 ntawm 2: Kev zam Tshwj Xeeb

Kauj Ruam 1. Saib xyuas qhov zam tshwj xeeb

Ib

InputMismatchException

raug pov tseg thaum tus neeg siv nkag mus rau cov ntaub ntawv uas tsis sib xws nrog hom thov. Piv txwv li, yog tias tus neeg siv nkag mus rau txoj hlua thaum ib tus int raug nug rau, txoj haujlwm yuav cuam tshuam

InputMismatchException

thiab tawm mus. Muaj ntau txoj hauv kev los daws qhov kev zam no thiab daws qhov teeb meem no kom koj txoj haujlwm tuaj yeem ua tsis ncaj.

Kauj Ruam 2. Siv lub block-try-catch block los daws qhov

InputMismatchException

.

ntshuam java.util. InputMismatchException; ntshuam java.util. Scanner; pej xeem chav kawm ScannerExample {pej xeem zoo li qub void lub ntsiab (Txoj hlua args) {// Pib lub Scanner tshiab scanner userInputScanner = Scanner tshiab (System.in); // Xeem nextLine (); System.out.print ("\ n Koj lub npe yog dab tsi?"); Txoj hlua lub npe = userInputScanner.nextLine (); // Xeem nextInt (); boolean validInput = tsis tseeb; int numberOfCats = 0; thaum (! validInput) {System.out.print ("Koj muaj pes tsawg tus miv?"); sim {numberOfCats = userInputScanner.nextInt (); validInput = muaj tseeb; } ntes (InputMismatchException e) {validInput = cuav; userInputScanner.nextLine (); }} // Xeem nextDouble (); validInput = tsis tseeb; ob npaug nyiajInWallet = 0.0; thaum (! validInput) {System.out.print ("Muaj nyiaj ntau npaum li cas hauv koj lub hnab nyiaj? $"); sim {moneyInWallet = userInputScanner.nextDouble (); userInputScanner.nextLine (); validInput = muaj tseeb; } ntes (InputMismatchException e) {validInput = cuav; userInputScanner.nextLine (); }} System.out.println ("\ n Nyob zoo" + npe + "! Koj muaj" + numberOfCats + (numberOfCats> 1? "Miv": "miv") + "thiab $" + moneyInWallet + "hauv koj lub hnab nyiaj. / n "); }}

• Nco ntsoov tias peb yuav tsum tau ntshuam

  java.util. InputMismatchException

  txhawm rau siv lub

  InputMismatchException

• chav kawm
• Peb tab tom siv lub sijhawm luv los nug tus neeg siv tib lo lus nug kom txog thaum tus neeg siv nkag mus rau qhov raug.

• Ntxiv

  userInputScanner.nextLine ();

• hauv kev ntes ib feem ntawm kev sim-ua kom ntseeg tau tias Lub Tshuab Luam Ntawv lees paub "nkag" qhov tseem ceeb nias los ntawm tus neeg siv thiab ua haujlwm raws li ib txoj hauv kev los tshem tawm cov khoom nkag.

Kauj Ruam 3. Xwb, ua rau tus neeg siv cov ntaub ntawv tsis raug cai los ntawm tsuas yog siv kab tom ntej los ntawm Scanner

Txoj hauv kev no, peb tuaj yeem ua kom ntseeg tau tias txhua yam uas Scanner rov qab yog cov khoom siv hlua thiab yuav tsis tsim ib qho kev zam. Tom qab ntawd, txhawm rau hloov cov hlua mus rau cov lej lossis ob npaug, peb tuaj yeem siv Chav Kawm Integer thiab Ob chav qhwv.

ntshuam java.util. Scanner; pej xeem chav kawm ScannerExample {pej xeem zoo li qub void lub ntsiab (Txoj hlua args) {// Pib lub Scanner tshiab scanner userInputScanner = Scanner tshiab (System.in); // Xeem nextLine (); System.out.print ("\ n Koj lub npe yog dab tsi?"); Txoj hlua lub npe = userInputScanner.nextLine (); // Xeem nextInt (); boolean validInput = tsis tseeb; int numberOfCats = 0; thaum (! validInput) {System.out.print ("Koj muaj pes tsawg tus miv?"); Txoj hlua tawm tswv yim = userInputScanner.nextLine (); sim {numberOfCats = Integer.parseInt (input); validInput = muaj tseeb; } ntes (NumberFormatException e) {validInput = cuav; }} // Xeem nextDouble (); validInput = tsis tseeb; ob npaug nyiajInWallet = 0.0; thaum (! validInput) {System.out.print ("Muaj nyiaj ntau npaum li cas hauv koj lub hnab nyiaj? $"); Txoj hlua tawm tswv yim = userInputScanner.nextLine (); sim {moneyInWallet = Double.parseDouble (input); validInput = muaj tseeb; } ntes (NumberFormatException e) {validInput = cuav; }} System.out.println ("\ n Nyob zoo" + npe + "! Koj muaj" + numberOfCats + (numberOfCats> 1? "Miv": "miv") + "thiab $" + moneyInWallet + "hauv koj lub hnab nyiaj. / n "); }}

• Nco ntsoov tias ntawm no peb tsis tas yuav ntshuam lub

  NumberFormatException

• chav kawm vim nws yog ib feem ntawm java.lang pob, uas txhais tau tias nws los ua hauv.

• Peb kuj tsis tas yuav tshem qhov tsis siv

  userInputScanner.nextLine ();

• hauv qhov ntes ntawm qhov sim-ntes.

Lub tswv yim

• Saib Scanner API kom paub ntau ntxiv txog kev siv chav kawm Scanner.
• Ib txwm siv.next () hloov ntawm.nextLine () los nyeem lo lus tom ntej, vim.nextLine () tuaj yeem ua rau kab mob.