How to check for a valid URL in Java?

Consider using the Apache Commons UrlValidator class

UrlValidator urlValidator = new UrlValidator();urlValidator.isValid("http://my favorite site!");

There are several properties that you can set to control how this class behaves, by default http, https, and ftp are accepted.

Here is way I tried and found useful,

URL u = new URL(name); // this would check for the protocolu.toURI(); // does the extra checking required for validation of URI 

I'd love to post this as a comment to Tendayi Mawushe's answer, but I'm afraid there is not enough space ;)

This is the relevant part from the Apache Commons UrlValidator source:

/** * This expression derived/taken from the BNF for URI (RFC2396). */private static final String URL_PATTERN =        "/^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\\?([^#]*))?(#(.*))?/";//         12            3  4          5       6   7        8 9/** * Schema/Protocol (ie. http:, ftp:, file:, etc). */private static final int PARSE_URL_SCHEME = 2;/** * Includes hostname/ip and port number. */private static final int PARSE_URL_AUTHORITY = 4;private static final int PARSE_URL_PATH = 5;private static final int PARSE_URL_QUERY = 7;private static final int PARSE_URL_FRAGMENT = 9;

You can easily build your own validator from there.