What is the principle of webservice?

It is a general model for building applications and can run in any operating system that supports network communication. It is a new branch of web application, which is self-contained, self-descriptive and modular, and can be published, located and called through the web. A Web service is an application component that logically provides data and services for other applications. Each application accesses the Web service through the network protocol and some specified standard data formats (Http, XML, Soap), and obtains the required results through the internal execution of the Web service. Web services can perform any function from simple requests to complex business processing. After deployment, other Web service applications can discover and invoke the services it deploys.

PS: Simply put.

Webservices is an application that exposes an API that can be called through the Web. In other words, you can call this application programmatically through the Web. We call the application that calls this web service a client.

When building and using Web services, the following key technologies and rules are mainly used:

Http transport channel

XML (Extensible Markup Language): A standard way to describe data.

SOAP (Simple Object Access Protocol): An information exchange protocol.

Wsdl (web service description language): web service description language.

Uddi (Universal Description, Discovery and Integration): Universal Description, Discovery and Integration. It is a platform-independent protocol based on XML language, which is used to describe the services on the Internet.