In this post, we will write a Java program to check if the String contains only Unicode letters or digits.
Program explanation:
- This program uses Character.isLetterOrDigit(cs.charAt(i) method to check if the character is letter or digit.
- testIsAlphanumeric() - JUnit test case for testing this program.
Java program to checks If the String Contains Only Letters or Digits
import static org.junit.Assert.assertFalse; import static org.junit.Assert.assertTrue; import org.junit.Test; /** * Program to Checks if the CharSequence contains only Unicode letters or digits * @author javaguides.net * */ public class IsAlphanumericExample { public static boolean isEmpty(final CharSequence cs) { return cs == null || cs.length() == 0; } 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; } @Test public void testIsAlphanumeric() { assertFalse(isAlphanumeric(null)); assertFalse(isAlphanumeric("")); assertFalse(isAlphanumeric(" ")); assertTrue(isAlphanumeric("a")); assertTrue(isAlphanumeric("A")); assertTrue(isAlphanumeric("kgKgKgKgkgkGkjkjlJlOKLgHdGdHgl")); assertFalse(isAlphanumeric("ham kso")); assertTrue(isAlphanumeric("1")); assertTrue(isAlphanumeric("hkHKHik6iUGHKJgU7tUJgKJGI87GIkug")); assertFalse(isAlphanumeric("_")); assertFalse(isAlphanumeric("hkHKHik*khbkuh")); } }
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