Deep understanding of URLs

URI (Universal Resource Identifier) ​​usually consists of three parts: ①The naming mechanism for accessing resources; ②The host name where the resource is stored; ③The name of the resource itself, represented by the path. Such as the following URI: http://www.webmonkey.com.cn/html/html40/

URL (Uniform Resource Locator), in layman’s terms, URL is a string describing information resources on the Internet. It is mainly used on various WWW clients and servers. It can use a unified format to describe information resources

Three parts of the URL format: The first part is the protocol (or service method).

　　　　　　　The second part is the IP address of the host where the resource is stored (sometimes including the port number
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 wealthgeneShe\ `\"The third part is the specific address of the host resource, such as directory and file name, etc. ​
The first part and the second part are separated by the "://" symbol, and the second part and the third part are separated by the "/" symbol. The first and second parts are indispensable, and the third part can sometimes be omitted.

Example: 1.URl example of http protocol: http://www.peopledaily.com.cn/channel/welcome.htm The computer domain name is www.peopledaily.com.cn. The hypertext file (file type: .html) is welcome.htm in the directory /channel. This is a computer from the People's Daily of China.

　　2. URL in file form

　　When using URL to represent a file, the server mode is represented by file, followed by the host IP address, file access path (i.e. directory) and file name and other information. Directory and file names can sometimes be omitted, but the "/" symbol cannot be omitted. Example: file://ftp.yoyodyne.com/pub/files/foobar.txt. The above URL represents a file stored in the pub/files/ directory on the host ftp.yoyodyne.com, and the file name is foobar.txt. Example: file://ftp.yoyodyne.com/pub represents the directory /pub on the host ftp.yoyodyne.com. Example: file://ftp.yoyodyne.com/ represents the root directory of the host ftp.yoyodyne.com.