Match Any Character Using Java Regex

The meta character “.” in java regular expression matches any character (single) it could be the alphabet, number or, any special character.

Example 1

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
   public static void main(String args[]) {
      //Reading String from user
      System.out.println("Enter a String");
      Scanner sc = new Scanner(System.in);
      String input = sc.nextLine();
      //Regular expression to match any character
      String regex = ".";
      //Compiling the regular expression
      Pattern pattern = Pattern.compile(regex);
      //Retrieving the matcher object
      Matcher matcher = pattern.matcher(input);
      int count = 0;
      while(matcher.find()) {
         count ++;
      }
      System.out.println("Given string contains "+count+" characters.");
   }
}

Output

Enter a String
hello how are you welcome to tutorialspoint
Given string contains 42 characters.

You can match any 3 characters between a and b using the following regular expression −

a…b

Similarly the expression “.*” matches n number of characters.

Example 2

Following Java program reads 5 strings from the user and accepts those which starts with b, ends with a with any number of characters in between them.

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample {
   public static void main( String args[] ) {
      String regex = "^b.*a$";
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter 5 input strings: ");
      String input[] = new String[5];
      for (int i=0; i<5; i++) {
         input[i] = sc.nextLine();
      }
      //Creating a Pattern object
      Pattern p = Pattern.compile(regex);
      for(int i=0; i<5;i++) {
         //Creating a Matcher object
         Matcher m = p.matcher(input[i]);
         if(m.find()) {
            System.out.println(input[i]+": accepted");
         } else {
            System.out.println(input[i]+": not accepted");
         }
      }
   }
}

Output

Enter 5 input strings:
barbara
boolean
baroda
ram
raju
barbara: accepted
boolean: not accepted
baroda: accepted
ram: not accepted
raju: not accepted