Task overview: Implementing Web services applications
Overview
WAS supports Web services based on a variety of Java programming models, operating across a variety of J2EE and non-J2EE platforms.
Web services allows one to integrate application systems together within or outside a company’s infrastructure. For example, to enable a customer database to be accessed by an accounting application, one could...
- Create a Web service for the customer database
- Enable the accounting application as a Web service client
Procedure
- Plan to use Web services.
Review...
- Migrate existing Web services.
Web services based on Apache SOAP, and client applications developed prior to WAS v5.0.2, should be migrated to Web Services for J2EE.
- Develop Web services applications...
- Use a JavaBeans implementation.
Transforming an existing application into Web services is called a bottoms-up approach to developing Web services.
- Use a stateless session enterprise bean.
Enterprise JavaBeans are only supported in JAX-RPC applications.
- Use an existing WSDL file using JavaBeans implementation.
Typically the WSDL is defined as part of the application modeling process. This is a top-down approach to developing Web services.
- Use an existing WSDL file using a stateless session enterprise bean.
Enterprise JavaBeans are supported in JAX-RPC applications only.
- Use service integration technologies (SIBWS)
- Take an internally-hosted service that is available at a bus destination, and make it available as a Web service.
- Take an external Web service, and make it available internally at a bus destination.
- Use the Web services gateway to map an existing service - either an internally-hosted service, or an external Web service - to a new Web service that seems to be provided by the gateway.
Web services can be developed to take advantage of...
- WS-Addressing
Provide address information in messages.
- Stateful Web services using WSRF.
Implement stateful Web services as WS-Resources that can be referenced using WS-Addressing.
- WS-Notification to enable "publish and subscribe" messaging .
Interoperate with publish and subscribe messaging clients such as JMS and WebSphere MQ.
Use NotificationBroker in highly available and workload managed configurations.
WS-Notification is supported in JAX-RPC applications only.
- Assemble Web services.
For creating *.ear files.
- Deploy Web services.
- Administer deployed Web services.
- Publish the WSDL file.
- Develop and deploy Web services clients.
- Secure Web services.
- Monitor the performance of Web services applications.
- Troubleshoot Web services.
- command-line tools
- Java compiling errors
- client runtime errors and exceptions
- serialization and deserialization errors
- authentication challenges and authorization failures
Example
The following example illustrates how a business might use Web services.
The owner of a flower shop wants to start receiving orders from customers through the Web. This owner starts the process by...
- Finding wholesale flower suppliers
- Pricing the product
- Completing contracts for future flower orders
The owner can use a UDDI registry to search for potential suppliers. When the suppliers are chosen, the registry sends back contact information on for flower distributors that meet the flower shop owner’s criteria.
The flower shop owner can request price lists from each of the suppliers by obtaining a WSDL file for each potential supplier. The WSDL can be...
- downloaded from the supplier’s Web page
- received through e-mail
- retrieved from the supplier’s UDDI registry entry.
The WSDL describes the procedure call. When using WAS, the procedure call is a JAX-RPC which retrieves price lists. The WSDL file also specifies the URL where the request is sent.
The flower shop owner now has to...
- compare the prices received back from each supplier,...
- decide which suppliers to do business with
- make arrangements for future orders to fill
The flower shop can now sell merchandise through the Web by using Web services to communicate with suppliers for the best prices and complete the ordering processes. The merchandise price lists need publishing to the Web site and a mechanism is needed for customers to order flowers.
The Web services clients of the flower supplier are deployed on the flower shop server. When a customer makes a transaction to purchase flowers through the Web, the order is sent to the supplier through the procedure call. The supplier responds by sending a confirmation with the order number and shipping date. The suppliers maintain the inventory and the flower shop owner handles billing and customer order management.
Similarly, the flower shop catalog can be composed automatically from the catalogs of all the suppliers. If the supplier ships directly to the customer, the order tracking inquiries can pass directly to the supplier’s order tracking system. The supplier can also use Web services to send invoices for orders and by the flower shop to pay the supplier’s invoices. Processes that previously required forms to fill manually, and fax or mail, can now be done automatically, saving labor costs for both the flower shop and the supplier.
Use Web services is beneficial because a much larger inventory is made available to the flower shop. No merchandise maintenance overhead exists, but the flower shop can offer their customers products that they otherwise might not have. Selling flowers through the Web increases capital for the flower shop without overhead of another store or money invested into additional product.
For a more detailed scenario, see Web services scenario: Overview which tells the story of a fictional online garden supply retailer named Plants by WebSphere and how they incorporated the Web services concept.
Service-oriented architecture
Web services
Plan to use Web services
Web services migration best practices
Migrate Apache SOAP Web services to Web Services for J2EE standards
Develop Web services applications from JavaBeans
Develop Web services applications from enterprise beans
Develop Web services applications from existing WSDL files with JavaBeans
Develop Web services applications from existing WSDL files with enterprise beans
Develop Applications that use Web Services Addressing
Create stateful Web services using the Web Services Resource Framework
Run an unmanaged Web services JAX-RPC client
Assemble Web services applications
Deploy Web services applications onto appservers
Administer deployed Web services applications
Make deployed Web services application available to clients
Develop and deploying Web services clients
Secure Web services applications at the transport level
Authenticate Web services clients using HTTP basic authentication
Test Web services-enabled clients
Monitor the performance of Web services applications
Tune Web services security for V6.1 applications
Secure Web services for V5.x applications based on WS-Security
Securing Web services applications using JAX-RPC at the message level
Troubleshooting Web services
Web services: Resources for learning
WAS roles and goals
Related concepts
Web Services for J2EE specification
JAX-RPC
WSDL
SOAP
SOAP with Attachments API for Java interface
Web Services-Interoperability Basic Profile
RMI-IIOP using JAX-RPC
WS-I Attachments Profile
Overview: Online garden retailer Web services scenarios
Web services approach to a service-oriented architecture
Web services business models supported
Related tasks
Enable Web services through service integration technologies
WS-Notification - publish and subscribe messaging for Web services
Related Reference
Web services SOAP/JMS protocol
Specifications and API documentation