You are familiar with URLs, and the other two words are unfamiliar. Uri, URL, and urn are the standard way to identify, locate, and name resources on the Internet.
In 1989, Tim Berners-Lee invented the Internet (World Wide Web ). WWW is regarded as a set of actual and abstract resources for global interconnection-it provides information entities as needed-and accesses through the Internet. The actual resources range from files to people. Abstract resources include database queries.
Because you need to identify resources in a variety of ways (the names of people may be the same, but computer files can only be accessed through a unique combination of path names ),
Therefore, we need a standard way to identify WWW resources. To meet this need, Tim Berners-Lee introduced a standard way to identify, locate, and name: URI, URL, and urn.
In this system, Uris, URLs, and urns are associated with each other. The category of URI is located at the top of the system, and the category of URL and urn is located at the bottom of the system. This sort shows that URL and urn are sub-categories of Uri. Uri indicates a unified resource ID, URL indicates a unified resource location, and urn indicates a unified Resource Name.