Uniform Resource Locator
Uniform Resource Locator (English: Uniform Resource Locator, abbreviation: URL, or Uniform Resource Locator, location address, URL address) is commonly known as web address, or URL for short. It is the address of a standard resource on the Internet, just like on the Internet. House number on the road. It was originally invented by Tim Berners-Lee as an address for the World Wide Web. It has now been compiled by the World Wide Web Consortium as an Internet standard RFC 1738.
In the history of the Internet, the invention of the Uniform Resource Locator is a very basic step. The syntax of the Uniform Resource Locator is general and extensible. It uses a part of the American Standard Code for Information Interchange to represent Internet addresses. The beginning of the Uniform Resource Locator generally marks the network protocol used by a computer network.
The standard format of the uniform resource locator is as follows:
[Protocol type]://[server address]:[port number]/[resource level UNIX file path][file name]?[query]#[fragment ID]
The complete format of the uniform resource locator is as follows:
[Protocol Type]://[Credentials Information Required to Access Resources]@[Server Address]:[Port Number]/[Resource Level UNIX File Path][File Name]?[Query]#[Fragment ID]
Among them, [Access Credentials Information], [Port Number], [Query], and [Fragment ID] are all optional items.
The Uniform Resource Locator of Hypertext Transfer Protocol includes the five basic elements of obtaining information from the Internet in a simple address:
Level URL mark symbol (for "//", fixed)
Credential information needed to access resources (can be omitted)
Server (usually a domain name, sometimes an IP address)
Port number (indicated by numbers, if it is the default value, it can be omitted)
Path (use the "/" character to distinguish each directory name in the path)
Query (The form parameters in GET mode start with the "?" character, each parameter is separated by "&", and then the parameter name and data are separated by "", usually encoded in UTF-8 URL, avoiding words The problem of meta conflict)
Fragment (starting with "#" character)
Take "https://zh.wikipedia.org:443/w/index.php?titlerandom page" as an example, where:
https, is the agreement;
zh.wikipedia.org is the server;
443 is the network port number on the server;
/w/index.php, is the path;
?titleSpecial: Random page, it is a query. Most web browsers do not require users to enter the "https://" part of the web page, because most web content is Hypertext Transfer Protocol files. Similarly, "443" is the commonly used port number for Hypertext Transfer Protocol documents (and "80" is the commonly used port number for Hypertext Transfer Protocol documents), so it is generally not necessary to specify it. Generally, users only need to type a part of the Uniform Resource Locator (such as "zh.wikipedia.org/w/index.php?titleSpecial:Random Page|Random Page").
Because the hypertext transfer protocol allows the server to redirect the browser to another web page address, many servers allow users to omit part of the web page address, such as "www". Technically speaking, the omitted web page address is actually a different web page address. The browser itself cannot determine whether this new address is accessible, and the server must complete the redirection task.
The Uniform Resource Locator is not only used as a web page address, but the JDBC client also uses the Uniform Resource Locator to connect to its database server. In contrast, ODBC's connection string has the same function, but it does not use URL format, but a key-value pair separated by semicolon and equal sign.
The following is a uniform resource locator for an Oracle database:
Uniform Resource Identifier (URI)
Uniform Resource Name (URN)
World Wide Web Consortium-Naming and Addressing (page archive backup, stored in the Internet Archive) (English)
Used for online URL decoding on the Internet (support Ascii, utf-8, big5, gb2312, euc-jp, euc-kr encoding, etc.) (page archive backup, stored in the Internet Archive)