What is scanner class in java?

Answer 1

The Scanner class alows users to enter data. Example:

import java.util.Scanner

Scanner scan = new Scanner (System.in);

String input;

System.out.println ("Enter a word or phrase.")

input = scan.nextLine ();

System.out.println ("You entered: " + input);

Answer 2

Searching Using the Scanner Class

Although the java.util.Scanner class is primarily intended for tokenizing data (which we'll cover next), it can also be used to find stuff, just like the Pattern and Matcher classes. While Scanner doesn't provide location information or search and replace functionality, you can use it to apply regex expressions to source data to tell you how many instances of an expression exist in a given piece of source data. The following program uses the first command-line argument as a regex expression, then asks for input using System.in. It outputs a message every time a match is found:

import java.util.*;

class ScannerTest {

public static void main(String[] args) {

System.out.print("input: ");

System.out.flush();

try {

Scanner s = new Scanner(System.in);

String token;

do {

token = s.findInLine(args[0]);

System.out.println("found " + token);

} while (token != null);

} catch (Exception e) { System.out.println("scan exc"); }

}

}

The invocation and input

java ScannerTest "\d\d"

input: 1b2c335f456

produce the following:

found 33

found 45

found null