Tell you in detail why XML is important to Web services

Web services are often described from the perspective of its component technology. SOAP, UDDI, WSDL, xml, and HTTP constitute part of the Web service system. they all play an important role. Let's take a look at the contribution of XML technology to the Web service platform. Web services are often described from the perspective of its component technology. SOAP, UDDI, WSDL, xml, and HTTP constitute part of the Web service system. they all play an important role. Let's take a look at the contribution of XML technology to the Web service platform.

Standardization

Compared with other Web service technologies, standardization is one of the characteristics of XML. XML provides a standard format for data transmission between Web service applications. The World Wide Web Consortium (W3C) manages XML standards and publishes them to global XML technology providers, which ensures the compatibility of XML products.

In addition to the XML engine and products, there are also XML syntax (grammar ). Each XML syntax is a standard method for formatting data in a specific domain. Following and using the XML syntax, you can standardize the data format for communication between two applications.

Interface Protocol

Programmers often call it a protocol when programming interfaces. From the programming point of view, the interface provides a programming structure without exposing the implementation. If you use DTD (file type definition) and schema, XML has similar features. Both DTD and outline are used to describe the structure of XML documents and the rules for creating XML documents. You can use one (or more) related DTD (or outline) to organize such a rule set, which is called XML syntax.

XML grammar can be used not only for standardization of communication between applications, but also for developers to provide an interface protocol. In other words, when creating an application that requires the structure of an XML document, the developer does not need to know how the document is implemented (that is, the actual XML document ). The DTD and outline describe the structure of the document, which can be used as the developed interface protocol. Any changes to the DTD also change the protocol.

Simplified

Another important aspect of XML documents is its simplification. I didn't imply that the implementation of XML is very simple, but that the concept and general method of XML are simple. For example, XML is based on text documents, which simplifies the process of opening an XML document and viewing its content.

It is also important to use XML to simplify the Web service model. Web services are naturally more complex than separate XML. Assume that XML and CORBA are equally complex, and other Web service technologies are the same, the Web service technology will become very cumbersome. However, by using simple building blocks, such as XML and SOAP, we can control the complexity of Web services within a tolerable range, in this way, the applications created with it will not be difficult to control.

Encapsulation

Encapsulation is one of my favorite XML features, especially when developing Web services. Essentially, encapsulation refers to the concept of obtaining one or more chunks of data and integrating them into a simple object (rather than several independent objects. Encapsulation is similar to aggregation, but there is an important difference between them, that is, encapsulation generally means that it has no external dependency.

You can create XML documents with external dependencies. However, it is wise to use encapsulation in the transactional Web services model. By designing an XML solution that encapsulates dependencies, you can generally eliminate problems in transaction processing. It is harmful to force external data to be located in a transaction and make it consistent with XML data, especially when external data is often changed. If the data is encapsulated into the XML syntax, the transaction will obtain the correct data.

The above is a detailed description of why XML is very important to Web services. For more information, see The PHP Chinese website (www.php1.cn )!