servlet paths

// http://hostname.com:80/mywebapp/servlet/MyServlet/a/b;c=123?d=789
    public static String getUrl3(HttpServletRequest req) {
        String scheme = req.getScheme();             // http
        String serverName = req.getServerName();     // hostname.com
        int serverPort = req.getServerPort();        // 80
        String contextPath = req.getContextPath();   // /mywebapp
        String servletPath = req.getServletPath();   // /servlet/MyServlet
        String pathInfo = req.getPathInfo();         // /a/b;c=123
        String queryString = req.getQueryString();          // d=789
    
        // Reconstruct original requesting URL
        String url = scheme+"://"+serverName+":"+serverPort+contextPath+servletPath;
        if (pathInfo != null) {
            url += pathInfo;
        }
        if (queryString != null) {
            url += "?"+queryString;
        }
        return url;
    }