URI,URN,URL三者的关系

Uniform resource identifier (URI）:

 scheme:[//[user[:password]@]host[:port]][/path][?query][#fragment]

Examples

The following figure displays two example URIs and their component parts.

hierarchical part

┌───────────────────┴─────────────────────┐

authority path

┌──────┴─────┐ ┌────────┴────────┐

abc://username:password@example.com:123/path/data?key=value&key2=value2#fragid1

└┬┘└───────┬────┘ └───────┬──┘ └───┬──────────┘└─────────┬─────────┘

scheme user information host port query fragment

urn:example:mammal:monotreme:echidna

└┬┘ └──────────────┬───────────────┘

scheme path

Uniform resource locator (URL)::

 scheme:[//[user[:password]@]host[:port]][/path][?query][#fragment]