Catching Errors as You Set Up URLs

When you set up a URL object, you must make sure the text used to set up the address is in a valid format. http://workbench.cadenhead.org and http://www.samspublishing.com are valid, but http:www.javaworld.com would not be because of missing “/” marks.

The getURL(String) method takes a web address as an argument, returning a URL object representing that address. If the string is not a valid address, the method returns null instead:

URL getURL(String urlText) {
    URL pageURL = null;
    try {
        pageURL = new URL(getDocumentBase(), urlText);
    } catch (MalformedURLException m) {
        // do nothing
    }
    return pageURL;
}

The try-catch block deals with any MalformedURLException errors that occur when URL objects are created. Because nothing needs to happen if this exception is thrown, the catch block only contains a comment.