Validate url

Programs that interact with the Internet might have the need to validate if a URL is valid. For instance, you might have a enter their URL on a comment made on your website or be accepting a feed from a third party application where you want to validate the URI to ensure proper formatting. This example will show how to check if a URL is valid URL using java regular expression, guava and apache commons.

Straight up Java

Using a java regular expression we will validate if a URL is valid.

@Test
public void validate_url_java () {
    
    String urlRegex = "\\b(https?|ftp|file|ldap)://"
            + "[-A-Za-z0-9+&@#/%?=~_|!:,.;]"
            + "*[-A-Za-z0-9+&@#/%=~_|]";
    
    assertTrue("http://www.leveluplunch.com".matches(urlRegex));
}

Google Guava

Feature request 1191 URLValidator exists in guava's backlog.

@Ignore("not yet implemented")
@Test
public void validate_url_guava () {
}

Apache Commons

Based on php script Apache commons URL UrlValidator has a series of routines or behavior that is checks for to validate a URL.

@Test
public void validate_url_apache_commons () {
    
    UrlValidator urlValidator = new UrlValidator();
    
    assertTrue(urlValidator.isValid("http://www.leveluplunch.com"));
}