im trying to understand where WSDL's fit in, in a typical web service backend application. i am coming from a Spring background and in my experience so far, in Spring, each url request gets mapped to a specific controller class via a dispate servlet running in the web container. you can specify which url matches a given controller via xml config or from annotations.
is using 开发者_JAVA百科a WSDL the same thing as using an xml config file to map url requests to java objects?
Thanks in advance. im moving from Spring to standard j2ee/EJB3.
WSDL is just a description of Web Service interface, most Web Service systems generate those descriptions on fly like for example when you create asmx web services you can generate WSDL on fly by typing http://yourhost/yourwebcontext/yourwebservicename.asmx?wsdl and it will return you the description of that web service. Then you can use a tools that generate stub proxies for coding using those descriptions automatically, for example in Visual Studio when you add an Web Service Reference those operations are done automatically
No, WSDLs are not like a dispatch servlet.
A WSDL file is a description of a web service (SOAP, REST, etc.). A WSDL can (theoretically) be used by anyone to generate executable code which consumes the web service described by that WSDL.
From the WSDL tag info:
"WSDL" stands for "Web Services Description Language." It is an XML language used to describe a web service to code that wishes to consume it. It describes the messages sent and received, the possible faults, and the communication and security requirements.
From WSDL Essentials:
In a nutshell, WSDL represents a contract between the service requestor and the service provider, in much the same way that a Java interface represents a contract between client code and the actual Java object. The crucial difference is that WSDL is platform- and language-independent and is used primarily (although not exclusively) to describe SOAP services.
Using WSDL, a client can locate a web service and invoke any of its publicly available functions. With WSDL-aware tools, you can also automate this process, enabling applications to easily integrate new services with little or no manual code. WSDL therefore represents a cornerstone of the web service architecture, because it provides a common language for describing services and a platform for automatically integrating those services.
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