XML Beginner's Tutorial: Understanding XML

[Introduction] xml is eXtensible Markup Language. Tags refer to information symbols that computers can understand. Through such tags, computers can process articles containing various information. How to define these tags, you can choose an internationally accepted markup language, such as HTM

xml or eXtensible Markup Language. Tags refer to information symbols that computers can understand. Through such tags, computers can process articles containing various information. How to define these tags, you can choose an internationally accepted markup language, such as HTML, or you can use a markup language like XML that is freely decided by the relevant people. This is the extensibility of the language. XML is simplified and modified from SGML. It mainly uses XML, XSL and XPath, etc.

The above paragraph is a basic definition of XML, a widely accepted explanation. Simply put, XML is a data description language. Although it is a language, it usually does not have the basic function of a common language - to be recognized and run by a computer. You can only rely on another language to interpret it so that it achieves the effect you want or is accepted by the computer.

If you are new to XML, you may not understand what XML is by definition. Perhaps, you can change your perspective to understand what XML is; understand XML from the application side, and understand it from what XML can do. This should be more helpful to you than the more empty definition.

XML application surface is mainly divided into two types, document type and data type. Here are some common XML applications:

1. Custom XML+XSLT=>HTML, one of the most common document-based applications. XML stores the XML data of the entire document, and then XSLT converts and parses the XML, combines it with the HTML tags in XSLT, and finally becomes HTML, which is displayed on the browser. A typical example is the post on CSDN.

2. XML, as a micro-database, is one of the most common data-based applications. We use relevant XML APIs (MSXML DOM, java DOM, etc.) to access and query XML. In the implementation of message boards, you can often see the use of XML as the database.

3. As communication data. The most typical one is WEB SERVICE, which uses XML to transfer data.

4. As configuration information data for some applications. Common ones are web.XML used when J2EE configures the WEB server.

5. XML format of some other documents. Such as Word, Excel, etc.

6. Save the mapping relationship between data. Such as Hibernate.

The 6 applications introduced here basically cover the main uses of XML. In short, XML is an abstract language that is not as concrete as traditional programming languages. To understand it in depth, you should start with its application, choose a use you need, and then learn how to use it.                    

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