java.util.Matcher

java.util.regex.Matcher is a class used to perform matching operations on text using a Pattern. It checks whether text matches a regular expression and can also find matching portions of text. Matcher is commonly used for validation, searching, extracting, and replacing text. It works closely with the Pattern class in the java.util.regex package.

Important Features:

• Checks complete text using matches().
• Searches for patterns using find().
• Retrieves matched text using group().
• Provides match positions using start() and end().
• Replaces matching text.
• Supports repeated searches through the same input.

Syntax:
Pattern pattern = Pattern.compile("regular_expression");
Matcher matcher = pattern.matcher("input");
boolean result = matcher.matches();Code language: JavaScript (javascript)

Example: Finding Numbers
Pattern pattern = Pattern.compile("[0-9]+");
Matcher matcher = pattern.matcher("My number is 12345");

while (matcher.find()) {
    System.out.println(matcher.group());
}Code language: JavaScript (javascript)

import java.util.regex.Pattern;
import java.util.regex.Matcher;

public class MatcherDemo {
    public static void main(String[] args) {

        Pattern pattern = Pattern.compile("[0-9]+");

        String input = "Java 17 is released in 2021";

        Matcher matcher = pattern.matcher(input);

        while (matcher.find()) {
            System.out.println("Found: " + matcher.group());
        }
    }
}

Output:
Found: 17
Found: 2021

Methods of Matcher