Utilizzando una re?
// Pattern for recognizing a URL, based off RFC 3986
private static final Pattern urlPattern = Pattern.compile(
"(?:^|[\\W])((ht|f)tp(s?):\\/\\/|www\\.)"
+ "(([\\w\\-]+\\.){1,}?([\\w\\-.~]+\\/?)*"
+ "[\\p{Alnum}.,%_=?&#\\-+()\\[\\]\\*$~@!:/{};']*)",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);