URL and URI

The definition of the URI is: Uniform Resource Identifier;
For a URL, the definition is: Uniform Resource Locator.
The difference is that the URI represents the path to the requesting server and defines such a resource. The URL also shows you how to access the resource

The URL is a subclass of the URI, that is, the URL is a URI, and the URI is not necessarily a URL.

The URL must be an absolute path and the URI can be a relative path.

In Java, the test is as follows:

Program:

    public void Dofilter (ServletRequest request, servletresponse response, Filterchain Filterchain) throws IOException,
            servletexception {
        //TODO auto-generated method Stub
        System.out.println (' do filter ');
        String uri= ((httpservletrequest) request). Getrequesturi ();
        StringBuffer url= (httpservletrequest) request). Getrequesturl ();
        System.out.println ("uri:" +uri);
        System.out.println ("URL:" +url);
        Filterchain.dofilter (request, response);


    

Output:
URI:/favicon.ico
Url:http://localhost:8090/favicon.ico