In computer networks, URL (Uniform Resource Locator, Uniform Resource Locator) is an identifier used to locate and access Internet resources. A URL usually consists of three parts: protocol, server address, and resource path.
For example, accessing the website https://www.example.com/about needs to use the HTTP protocol, the server address to be accessed is www.example.com, and the resource path is /about, then its URL can be expressed as:
http://www.example.com/about
Among them:
protocol (http) refers to the communication protocol used when accessing the resource, including HTTP, FTP, HTTPS, SMTP, etc.;
server address (www.example.com) refers to the host name or IP address where the resource is located, which can be Domain name or IP address;
resource path (/about) refers to the relative address or absolute path of the resource on the server, which can be a file, directory, dynamic page, etc.
URL is one of the most important ways to access Internet resources. You can access network resources through browsers, command line tools such as curl, etc., and network libraries in many programming languages. On the Internet, almost all resources, including web pages, pictures, videos and other files, can be accessed through URLs.