Java five introduced a dainty utility called java.util.Scanner which is capable of reading input shape ascendence job inwards Java. Using Scanner is a dainty together with cook clean agency of retrieving user input from console or ascendence line. The scanner tin convey InputStream, Reader or exactly path of the file from where to read input. In social club to read from the ascendence line, nosotros tin exceed System.in into Scanner's constructor equally a root of input. The scanner offers several do goodness over classical BufferedReader approach, hither are closed to of the benefits of using java.util.Scanner for reading input from ascendence job inwards Java:
1) The scanner supports regular expression, which gives you lot the ability to read exclusively matching the designing from the input.
2) The scanner has methods similar nextInt(), nextFloat() which tin move used to read numeric input from ascendence job together with tin move lead used inwards code without using Integer.parseInt() or whatever other parsing logic to convert String to Integer or String to double for floating quest input.
Reading input from the ascendence job should move the starting fourth dimension few matter which novel Java programmer should move taught equally it helps them to write an interactive programme together with consummate programming practise similar checking for a prime number, finding the factorial of a number, reversing String etc. Once you lot are comfortable reading input from the ascendence job you lot tin write many interactive Java application without learning in GUI applied scientific discipline similar Swing or AWT.
Java programme to read input from ascendence prompts inwards Java
Here is sample code instance of How to read input from the ascendence job or ascendence prompt in Java using java.util.Scanner class:
import java.io.IOException;
import java.util.Scanner;
public class ReadInputScannerExample {
public static void main(String args[]) throws IOException {
Scanner scanner = new Scanner(new InputStreamReader(System.in));
System.out.println("Reading input from console using Scanner inwards Java ");
System.out.println("Please come inwards your input: ");
String input = scanner.nextLine();
System.out.println("User Input from console: " + input);
System.out.println("Reading int from console inwards Java: ");
int publish = scanner.nextInt();
System.out.println("Integer input: " + number);
}
}
Output:
Reading input from console using Scanner inwards Java
Please come inwards your input:
number
User Input from console: number
Reading int from console inwards Java:
1232
Integer input: 1232
import java.util.Scanner;
public class ReadInputScannerExample {
public static void main(String args[]) throws IOException {
Scanner scanner = new Scanner(new InputStreamReader(System.in));
System.out.println("Reading input from console using Scanner inwards Java ");
System.out.println("Please come inwards your input: ");
String input = scanner.nextLine();
System.out.println("User Input from console: " + input);
System.out.println("Reading int from console inwards Java: ");
int publish = scanner.nextInt();
System.out.println("Integer input: " + number);
}
}
Output:
Reading input from console using Scanner inwards Java
Please come inwards your input:
number
User Input from console: number
Reading int from console inwards Java:
1232
Integer input: 1232
Just banknote that java.util.Scanner nextInt() volition throw "Exception inwards thread "main" java.util.InputMismatchException" exception if you lot entered String or grapheme information which is non publish piece reading input using nextInt(). That’s all on how to read user input from the ascendence job or ascendence prompt inwards Java. Further Learning
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