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Java regular expression meta-character \b

Sub-expression/The meta-character " \b Matches the word boundary outside the brackets. Matches the space inside the parentheses (0x08)。

Example1

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 = \\\\bbecause\\\b;
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter a string:");
      String input = sc.nextLine();
      Pattern p = Pattern.compile(regex);
      Matcher m = p.matcher(input);
      int count = 0;
      while(m.find()) {
         count ++;
      }
      System.out.println("Number of matches:");+count);
   }
}

Output Result

Enter a string:
A sentence doesn't end with because because, because is a conjunction
Number of matches: 3

Example2

The following Java example reads a string value from the user and prints the number of word boundaries.

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
   public static void main(String args[]) {
      System.out.println("Enter input string:");
      Scanner sc = new Scanner(System.in);
      String input = sc.nextLine();
      String regex = "\\b";
      //Compile regular expression
      Pattern pattern = Pattern.compile(regex);
      //Retrieve matcher object
      Matcher matcher = pattern.matcher(input);
      int count = 0;
      while(matcher.find()) {
         count ++;
      }
      System.out.println(count);
   }
}

Output Result

Enter input string:
Hello, how are you? Welcome to w3codebox
14