WebService's agreement

The Web service uses a SOAP (Simple Object access Protocol), a protocol specification for exchanging data, a lightweight, simple protocol based on XML (a subset of the standard Universal Markup Language). It is designed to exchange structured and solidified information on the web.
The SOAP protocol is used only to encapsulate messages. The encapsulated message can be transmitted through a variety of existing protocols, such as HTTP, TCP/IP, SMTP, and so on, even once with a custom protocol, and of course can be used with HTTPS protocol soap and many existing Internet protocols and formats, including Hypertext Transfer Protocol (HTTP), Simple Mail Transfer Protocol (SMTP), Multipurpose Internet Mail Expansion Protocol (MIME). It also supports a large number of applications, from the messaging system to Remote procedure calls (RPCs). SOAP uses a combination of XML-based data structures and Hypertext Transfer Protocol (HTTP) to define a standard method for using distributed objects in various operating environments on the Internet.
Soap is built on HTTP, and it's plain to use HTTP to send XML.

In addition to WebService, common remote invocation techniques include RMI (remote method Invoke) and CORBA, which are more widely used than the other two technologies due to the WebService cross-platform and cross-programming language features, but with slightly lower performance.

WebService Use SOAP protocols for cross-programming languages and cross-OS platforms

WebService transmits data using the HTTP protocol, encapsulating the data in XML format (that is, what method of invoking the remote service object in XML, what parameters are passed, and what the service object returns).

WebService sends requests and receives results through the HTTP protocol, both the requested content and the resulting content are encapsulated in XML format, and some specific HTTP message headers are added to describe the content format of the HTTP message. These specific HTTP message headers and XML content formats are the SOAP protocol (Simple Object Access Protocol, and the trivial objects accessing protocol).

SOAP Protocol = HTTP Protocol + XML Data Format

The SOAP protocol is based on the HTTP protocol, and the relationship between the two is similar to the highway is based on the ordinary highway transformation, on a highway added to the fence is a highway.

As long as the clerk receives the money, the store waiter provides the goods to the customer, the store attendant does not care about the nature of the customer, and the customer does not care about the nature of the store attendant. Similarly, the WebService client can use the HTTP protocol to send XML request data that follows a certain format to the WebService server, and the WebService server returns the XML result data that follows some format via the HTTP protocol. WebService client and server do not care about what programming language is used by the other side.

HTTP protocol and XML are widely used general technology, the various programming languages to the HTTP protocol and XML both provide very good support, WebService client and server-side use of what programming language can complete the function of soap, so, WebService is easy to implement across programming languages, and cross programming languages naturally cross the operating system platform

WebService's agreement