Program to match vowels in a string using regular expression in Java

You can group all the required characters to match within the square braces “[ ]” i.e. The metacharacter/sub-expression “[ ]” matches all the specified characters. Therefore, to match all the letters specify the vowel letters within these as shown below −

[aeiouAEIOU]

Example 1

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class MatchVowels {
   public static void main( String args[] ) {
      String regex = "[aeiouAEIOU]";
      System.out.println("Enter input string: ");
      Scanner sc = new Scanner(System.in);
      String input = sc.nextLine();
      //Compiling the regular expression
      Pattern.compile(regex);
      //Compiling the regular expression
      Pattern pattern = Pattern.compile(regex);
      Matcher matcher = pattern.matcher(input);
      if(matcher.find()) {
         System.out.println("The input string contains vowels");
      } else {
         System.out.println("The input string does not contain vowels");
      }
   }
}

Output

Enter input string:
hello how are you welcome
The input string contains vowels

Example 2

import java.util.Scanner;
public class Test {
   public static void main( String args[] ) {
      String regex = "[aeiouAEIOU]";
      System.out.println("Enter input string: ");
      Scanner sc = new Scanner(System.in);
      String input = sc.nextLine();
      boolean result = input.matches(regex);
      if(result) {
         System.out.println("The input string contains vowels");
      } else {
         System.out.println("The input string does not contain vowels");
      }
   }
}

Output

Enter input string:
hello how are you welcome
The input string does not contain vowels