How to replace multiple spaces in a string with a single space using Java regular expressions?

Meta character"\\s"Matches a space+Represents a space appearing once or multiple times, therefore, the regular expression\\ S +Matches all space characters (single or multiple). Therefore, replace multiple spaces with a single space.

Match the input string with the above regular expression and then replace the result with a single space "".

Example1

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class ReplaceAllExample {
　　　public static void main(String args[]) {
　　　　　　//Read a string from the user
　　　　　　System.out.println("Enter a String");
　　　　　　Scanner sc = new Scanner(System.in);
　　　　　　String input = sc.nextLine();
　　　　　　String regex = "\\s"+";
　　　　　　//Compile the regular expression
　　　　　　Pattern pattern = Pattern.compile(regex);
　　　　　　//Retrieve the matcher object
　　　　　　Matcher matcher = pattern.matcher(input);
　　　　　　//Replace all space characters with a single space
　　　　　　String result = matcher.replaceAll(" ");
　　　　　　System.out.print("Text after removing unwanted spaces: 
"+result);
　　　}
}

Output Result

Enter a String
hello this is a sample text with irregular spaces
Text after removing unwanted spaces:
hello this is a sample text with irregular spaces

Example2

import java.util.Scanner;
public class Test {
　　　public static void main(String args[]) {
　　　　　　//Read a string from the user
　　　　　　System.out.println("Enter a String");
　　　　　　Scanner sc = new Scanner(System.in);
　　　　　　String input = sc.nextLine();
　　　　　　//Regular expression to match spaces
　　　　　　String regex = "\\s"+";
　　　　　　//Replace pattern with a single space
　　　　　　String result = input.replaceAll(regex, " ");
　　　　　　System.out.print("Text after removing unwanted spaces: 
"+result);
　　　}
}

Output Result

Enter a String
hello this is a sample text with irregular spaces
Text after removing unwanted spaces:
hello this is a sample text with irregular spaces