JAVA EE: How to capturing the groups in Regex | Java Regex | Java Regular Expressions

Friday 5 January 2018

How to capturing the groups in Regex | Java Regex | Java Regular Expressions | Regex in java

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RegexDemo.java

import java.util.regex.Matcher;

import java.util.regex.Pattern;

/**

 *

 * Capturing Groups

 *

 */

public class RegexDemo

{

    public static void main(String[] args)

    {

        /*

         * The API also allows us to treat multiple digits as a

         * single unit through capturing groups.

         */

        isMatch("(\\d\\d)", "12");

        isMatch("(\\d\\d)", "123");

        isMatch("(\\d\\d)", "a2");

    }

    private static void isMatch(String regex, String inputText)

    {

        Pattern pattern = Pattern.compile(regex);

        Matcher matcher = pattern.matcher(inputText);

        System.out.println("Regex = " + regex + " , " + "InputText = "

                + inputText + " is matching? = " + matcher.matches());

    }

}

Output

Regex = (\d\d) , InputText = 12 is matching? = true

Regex = (\d\d) , InputText = 123 is matching? = false

Regex = (\d\d) , InputText = a2 is matching? = false