Scanner Class in Java

Scanner class is used to read input from keyboard. Scanner is class in java.util package. Scanner class provides many methods to read and parse primitive values. Scanner breaks the input into tokens using delimiter which is by default whitespaces. 

To read input from keyboard, we have to make an object of Scanner class by passing predefined object called System.in.

Example:

Scanner sc = new Scanner(System.in);

Here sc is object of Scanner class and System.in represents the standard input stream.

In java.util package, Scanner class extends Object class and implements Iterator and Closeable interfaces.

Methods in Scanner Class

There are many methods in Scanner class but most commonly used methods are:

1. next() is used to take single word input

2. nextInt() is used to take integer input

3. nextFloat() is used to take float input

4. nextDouble() is used to take double input

5. nextLong() is used to take long input

6. nextShort() is used to take short input

7. nextLine() is used to take string input

8. nextBoolean() is used to take boolean input

next().charAt(0). is used to read a single character.

Example of Java Scanner Class

import java.util.Scanner;
class ScannerExample{
 public static void main(String[] args) {
  Scanner sc = new Scanner(System.in);

  System.out.print("Enter a String : ");
  String s = sc.nextLine();
  System.out.println("You have entered "+s);

  System.out.print("\nEnter Integer Value : ");
  int a = sc.nextInt();
  System.out.println("You have entered "+a);

  System.out.print("\nEnter Character Value : ");
  char c = sc.next().charAt(0);
  System.out.println("You have entered "+c);
 }
}

Output:

Enter a String : Java
You have entered Java

Enter Integer Value : 10
You have entered 10

Enter Character Value : B
You have entered B