JAVA

java code to check if string is alphanumeric

java.util.regex.*;
class AlphanumericExample
{
  public static void main(String...s)
  {
    String s1="adA12", s2="jh@l";
    System.out.println(s1.matches("[a-zA-Z0-9]+"));
    System.out.println(s2.matches("[a-zA-Z0-9]+"));
  }
}

check character is alphanumeric java

 javaCopypublic class CheckCharAlpha {
    public static void main(String[] args) {

        boolean letterOrDigit = isAlphaNumeric('k');
        System.out.println(letterOrDigit);
    }

    public static boolean isAlphaNumeric(char char1) {
        return (char1 >= 'a' && char1 <= 'z') || (char1 >= 'A' && char1 <= 'Z') || (char1 >= '0' && char1 <= '9');
    }
}