Apart from reading
file, Scanner can also read user input from Console in Java. Just like in
case of reading file, we have provided File as source
for scanning, We need to provide System.in as source
to scan for user input in Console. Once you created and initialized java.util.Scanner, you can
use its various read method to read
input from user. If you want to read String, you can use nextLine(), if you
want to read integer numbers, you can use nextInt().
Subsequently you can use nextFloat() to read float input, nextDouble() to read
double input etc. Scanner class also allows you to define your own pattern and
scan for that.
Reading User Input using Scanner in Java - Example
Let's see a complete code example of reading user input using Scanner class. In
this Java program we are reading User Input in form of String using Scanner's nextLine() method and
numbers particular integer using nextInt() method of
Scanner. Scanner is created by passing System.in which is a InputStream as source which means
it will scan input console for data.
/**
*
* Java program to read input from console using Scanner in Java
* We pass System.in as source to Scanner which then scan Console for user input
* @author
*/
public class UserInputExample {
public static void main(String args[]) {
//Creating Scanner instance to scan console for User input
Scanner console = new Scanner(System.in);
System.out.println("System is ready to accept input, please enter name : ");
String name = console.nextLine();
System.out.println("Hi " + name + ", Can you enter an int number now?");
int number = console.nextInt();
System.out.println("You have entered : " + number);
System.out.println("Thank you");
}
}
Output:
System is ready to accept input, please enter name :
John
Hi John, Can you enter an int number now?
56
You have entered : 56
Thank you
*
* Java program to read input from console using Scanner in Java
* We pass System.in as source to Scanner which then scan Console for user input
* @author
*/
public class UserInputExample {
public static void main(String args[]) {
//Creating Scanner instance to scan console for User input
Scanner console = new Scanner(System.in);
System.out.println("System is ready to accept input, please enter name : ");
String name = console.nextLine();
System.out.println("Hi " + name + ", Can you enter an int number now?");
int number = console.nextInt();
System.out.println("You have entered : " + number);
System.out.println("Thank you");
}
}
Output:
System is ready to accept input, please enter name :
John
Hi John, Can you enter an int number now?
56
You have entered : 56
Thank you
That's all on How to read user input using Scanner in Java program.
Scanner allows you to read various types of input directly from User without
extra conversion e.g. you can read int, float, long , double or String
directly.
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