JAVA EE: What is the difference between lookingAt and matches methods of matcher class

Monday 25 December 2017

What is the difference between lookingAt and matches methods of matcher class | Regex in java

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RegexDemo.java

import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class RegexDemo

{

    public static void main(String[] args)

    {

        String inputCharSeq = "Hello peter how are you?";

        String regex = "Hello peter";

        Pattern pattern = Pattern.compile(regex);

        Matcher matcher = pattern.matcher(inputCharSeq);

        /*

         * The Matcher lookingAt() method works like the matches()

         * method with one major difference.

         * 

         * The lookingAt() method only matches the regular expression

         * against the beginning of the text, whereas matches()

         * matches the regular expression against the whole text.

         * 

         * In other words, if the regular expression matches the

         * beginning of a text but not the whole text, lookingAt()

         * will return true, whereas matches() will return false.

         */

        System.out.println("lookingAt = " + matcher.lookingAt());

        System.out.println("matches   = " + matcher.matches());

    }

}