Character class p{javaWhitespace} Java regex in java.

This character class \p{javaWhitespace} matches spaces. This class matches the characters which returns true when passed as a parameter to the isWhitespace() method of the java.lang.Character class.

Example 1

 Live Demo

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample {
   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
      String regex = "[\p{javaWhitespace}]";
      //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("Number of upper case characters: "+count);
   }
}

Output

Enter a string
hello welcome to tutorialspoint
Number of upper case characters: 3

Example 2

 Live Demo

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
   public static void main( String args[] ) {
      //Regular expression to match lower case letters
      String regex = "^\p{javaWhitespace}+$";
      //Getting the input data
      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);
      System.out.println("Strings with only upper case characters: ");
      for(int i=0; i<5;i++) {
         //Creating a Matcher object
         Matcher m = p.matcher(input[i]);
         if(m.matches()) {
            System.out.println(m.group());
         }
      }
   }
}

Output

Enter 5 input strings:
Raju
RAMU
rahman
radha
SUnDar*
Strings with only upper case characters:
RAMU