The difference between a URI URL urn

A: What is Uri,url,urn?

Uri:uniform Resource Identifier, a Uniform Resource identifier, is a string used to represent the name of a resource on the Internet

　　　　format:http://www.xxx.com:80/home/index.html?page=2

Url:uniform Resource Locator, a Uniform Resource locator that describes a specific location for a specific resource on a specific server

Urn:uniform Resource name, Uniform Resource name, name to locate the resource, and the location of the resource is irrelevant

Two: Difference

Summarize:

I>:uri: There are two forms, namely URL, URN.

Ii>:uri is a generic concept that defines uniform resource flags in an abstract concept, while URLs and urns are specific resource flags.

Iii>: To remember that URIs are abstract, URLs, urns are specific

The difference between a URI URL urn