android中判断一个链接是否是有效的

private boolean isValid(String urlString)
{
    try
    {
        URL url = new URL(urlString);
        return URLUtil.isValidUrl(urlString) && Patterns.WEB_URL.matcher(urlString).matches();
    }
    catch (MalformedURLException e)
    {

    }

    return false;
}