Check If a String Contains Any Special Character in Java

In Java, checking if a string contains special characters can be easily done using regular expressions. We will be using the Pattern and Matcher classes from the java.util.regex package, we can efficiently determine whether a string includes any special characters. In this article, we will demonstrate how to use these classes to perform the check and handle the result accordingly. ?

Problem Statement

For a given string write a Java program to check if it contains any special character or not ?

Input 1

I Love Tutorialspoint

Output 1

Special character not found in the string

Input 2

This is a sample only !$@

Output 2

Special character found in the string

Step to check if a string contains any special character 

Following are the steps to check if a string contains any special character ?

• Import the Pattern and Matcher classes from the java.util.regex package.
• Initialize a string that may or may not contain special characters.
• Use Pattern.compile() to create a pattern that identifies special characters.
• Create a Matcher object and use the find() method to check for any special characters in the string.
• Print a message depending on whether special characters are found.

Java program to check if a string contains any special character

Below is the Java program to check if a string contains any special characters ?

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Demo {
    public static void main(String[] args) {
        String my_str="This is a sample only !$@";
        Pattern my_pattern = Pattern.compile("[^a-z0-9 ]", Pattern.CASE_INSENSITIVE);
        Matcher my_match = my_pattern.matcher(my_str);
        boolean check = my_match.find();
        if (check)
            System.out.println("Special character found in the string");
        else
            System.out.println("Special character not found in the string");
    }
}

Output

Special character found in the string

Code Explanation

A class named Demo contains the main function, where a string is defined, with some special characters. A pattern that uses regular expressions to check if the string has any special characters is described. A Boolean value is specified, that checks to see for the same. If the value of Bool is true, a success message is printed, otherwise, a message stating the absence of these special characters is printed on the screen.