JAVA EE: How to use replaceAll and replaceFirst methods of matcher class

Tuesday, 19 December 2017

How to use replaceAll and replaceFirst methods of matcher class | Regex in java

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RegexDemo1.java

import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class RegexDemo1

{

    private static String REGEX = "lion";

    private static String INPUT = "The lion says meow. All lions say meow.";

    private static String REPLACE = "cat";

    public static void main(String[] args)

    {

        Pattern pattern = Pattern.compile(REGEX);

        Matcher matcher = pattern.matcher(INPUT);

        /*

         * Parameters:

         * 

         * replacement - The replacement string

         * 

         * Returns: 

         * 

         * The string constructed by replacing each matching

         * subsequence by the replacement string, substituting

         * captured subsequences as needed

         */

        INPUT = matcher.replaceAll(REPLACE);

        System.out.println(INPUT);

    }

}

Output

The cat says meow. All cats say meow.

RegexDemo2.java

import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class RegexDemo2

{

    private static String REGEX = "lion";

    private static String INPUT = "The lion says meow. All lions say meow.";

    private static String REPLACE = "cat";

    public static void main(String[] args)

    {

        Pattern pattern = Pattern.compile(REGEX);

        Matcher matcher = pattern.matcher(INPUT);

        /*

         * Parameters:

         * 

         * replacement - The replacement string

         * 

         * Returns:

         * 

         * The string constructed by replacing the first matching

         * subsequence by the replacement string, substituting

         * captured subsequences as needed

         */

        INPUT = matcher.replaceFirst(REPLACE);

        System.out.println(INPUT);

    }

}