Java String isAlphanumeric() Utility Method

Java String Utility Methods


This page contains the source code of Java String isAlphanumeric() utility method - This method checks if the CharSequence contains only Unicode letters or digits.

Java String isAlphanumeric() Utility Method

The following String isAlphanumeric() utility method checks if the CharSequence contains only Unicode letters or digits:
/**
  * <p>
  * Checks if the CharSequence contains only Unicode letters or digits.
  * </p>
  *
  * <p>
  * {@code null} will return {@code false}. An empty CharSequence
  * (length()=0) will return {@code false}.
  * </p>
  * 
  * @param cs
  *            the CharSequence to check, may be null
  * @return {@code true} if only contains letters or digits, and is non-null
  * @since 3.0 Changed signature from isAlphanumeric(String) to
  *        isAlphanumeric(CharSequence)
  * @since 3.0 Changed "" to return false and not true
  */
 public static boolean isAlphanumeric(final CharSequence cs) {
     if (isEmpty(cs)) {
         return false;
     }
     final int sz = cs.length();
     for (int i = 0; i < sz; i++) {
         if (!Character.isLetterOrDigit(cs.charAt(i))) {
             return false;
         }
     }
     return true;
 }





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