Difference Between URL and URI

Understand: uri: A string that identifies Internet resources, which is unique, and url is a uri that can access resources (url must also be unique);

Take a chestnut: you can treat the ID card as a uri, but not a url;

//Earth/China/Zhejiang Province/Hangzhou City/Xihu District/A University/Dormitory Building No. 14/Dormitory No. 525/ID Card --> This can be counted as a url and can locate resources; (of course he is also a uri )

In addition, there is a good blog: http://www.cnblogs.com/hust-ghtao/p/4724885.html