The program checks if the string is alphanumeric

Any word containing both numbers and letters is called alphanumeric. The following regular expression matches combinations of numbers and letters.

"^[a-zA-Z0-9]+$";

The match method of the String class accepts a regular expression (in the form of String) and matches it with the current string, in case the match method returns true, it returns false.

Therefore, to find out whether a specific string contains alphanumeric values-

• Get the string.

• Bypass the match method mentioned above by calling the regular expression.

• Retrieve the result.

Example1

import java.util.Scanner;
public class AlphanumericString {
　　　public static void main(String args[]) {
　　　　　　Scanner sc = new Scanner(System.in);
　　　　　　System.out.println("Enter input string: ");
　　　　　　String input = sc.next();
　　　　　　String regex = "^[a-zA-Z0-9]+$";
　　　　　　boolean result = input.matches(regex);
　　　　　　if(result) {
　　　　　　　　　System.out.println("Given string is alphanumeric");
　　　　　　} else {
　　　　　　　　　System.out.println("Given string is not alphanumeric");
　　　　　　}
　　　}
}

Output Result

Enter input string:
abc123*
Given string is not alphanumeric

Example2

You can also usejava.util.regexThe class and method (API) of the package compile regular expressions and match them with a specific string. The following program is written using these APIs and it verifies whether the given string is alphanumeric.

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Test {
　　　public static void main( String args[] ) {
　　　　　　Scanner sc = new Scanner(System.in);
　　　　　　System.out.println("Enter input string: ");
　　　　　　String input = sc.nextLine();
　　　　　　String regex = "^[a-zA-Z0-9]+$";
　　　　　　String data[] = input.split("　");
　　　　　　//Create a pattern object
　　　　　　Pattern pattern = Pattern.compile(regex);
　　　　　　for (String ele : data) {
　　　　　　　　　//Create a match object
　　　　　　　　　Matcher matcher = pattern.matcher(ele);
　　　　　　　　　if(matcher.matches()) {
　　　　　　　　　　　　System.out.println("The word "+ele+: is alpha numeric);
　　　　　　　　　} else {
　　　　　　　　　　　　System.out.println("The word "+ele+: is not alpha numeric);
　　　　　　　　　}
　　　　　　}
　　　}
}

Output Result

Enter input string:
hello*　this$ is sample text
The word hello*: is not alpha numeric
The word this$: is not alpha numeric
The word is: is alpha numeric
The word sample: is alpha numeric
The word text: is alpha numeric