1. What is WebService?
WebService is a programming language and cross-platform operating system across remoting technology. WebService is an application exposed to the outside world via a Web API calls, the programming method that is able to call this application over the Web. We call this WebService application called the client, and to provide this WebService application called the service side.
2, using conventional techniques WebService
XML + XSD, SOAP and WSDL is composed of three WebService technology platform.
1 "XML + XSD: WebService HTTP protocol to transmit data, the data package in XML format (i.e., the XML description method which calls the remote service object, what parameters are passed, and returns a result of what service objects). XML solves the problem of data representation, but it does not define a standard set of data types, but does not say how to extend this set of data types. XML Schema (XSD) is a set of standards specifically address this issue. It defines a set of standard data types, and gives a language to extend the set of data types.
2 "soap: Simple Object Access Protocol. When WebService send requests and receive results using the HTTP protocol, the request content and the results of the content transmission are in XML format package, and adds some specific HTTP message header, to indicate the content of the format of the HTTP message, these specific HTTP header and XML content format is SOAP protocol. SOAP protocol defines the format of the SOAP message, SOAP is a protocol based on HTTP protocol, SOAP is based on XML and XSD, XML is SOAP encoding of data.
SOAP protocol = HTTP + XML protocol agreement
3 "WSDL: Web Services Description Language. WebService business end first through a WSDL file shows that he provides what services can be outside call, what services (which methods the service there, what method accepts parameters are, what the return value), service network access address which url address with said service by what means to call. The equivalent of publishing services for use. WSDL is an XML-based standard format for WebService client and server can understand.
3, java related WebService framework
Typical aspects of Java WebService framework include: axis, xfire, cxf etc., java ee server usually supports publishing, such as Tomcat.
4, WebService significant advantages
1 "Cross-platform invoke
2 "boast language calls
3 "Remote Procedure Call
4 "Distributed Applications