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There are several reasons why Web Services has become a need:

1. One of the biggest reason why we need web services reasons is interoperability wherein different Vendor vendor specific applications can interact with each other. For Example a .Net application accessing a Java web service.
2. Using Web Services you can expose your application and its functionality globally.
3. Using Web Services, an enterprise need would not not depend on one particular vendor for all the solutions. It can move to different vendors for different functionality and can optimally choose out of several options.
4. Web Services used use standardized protocols SOAP, UDDI, WSDL and HTTP for implementation.
5. Web Services has support for most of the communication protocol and it can be implemented using FTP as well as HTTP.
6. Web Services follow a loosely coupled architecture.

Web Services Architecture

As can be seen from the architecture diagram, the Web Service Provider registers the Web Service to UDDI registry and provides WSDL for invoking service. The Web Service consumer, which can be an application client or any other Web Service, queries the UDDI registry and finds WSDL. Next the consumer uses WSDL to invoke the SOAP service.

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• <service>- Service element defines where the service can be accessed. Each service is associated with a unique name which is suggested by <wsdl:service name="HelloWorldService"> in our example. The next element <wsdl:port binding="intf:HelloWorldSoapBinding" name="HelloWorld"> suggests the previous binding which will be used by service. The element <wsdlsoap:address location="http://localhost:8080/SimpleWeb/services/HelloWorld"/> suggests the physical address through which a service can be accessed.

Web

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Services tutorials