WAS v8.5 > End-to-end paths > Web services - RESTful services

Implement JAX-RS web applications

We can use Java API for RESTful Web Services (JAX-RS) to develop services that follow REST principles. Using JAX-RS, development of RESTful services is simplified.

JAX-RS is a Java API for developing REST applications quickly. This standard API continues to gain support throughout the Java community. While JAX-RS provides a faster way of developing web applications than servlets, the primary goal of JAX-RS is to build RESTful services. JAX-RS 1.0 defines a server-side component API to build REST applications. IBM JAX-RS provides an implementation of the JAX-RS (JSR 311) specification.

By using the principles of REST, your business applications can benefit from several advantages. RESTful services are generally simpler to develop and consume. Most RESTful services use well-defined standards for delivery such as HTTP. Because HTTP is a protocol that has RESTful properties, RESTful services gain scalability advantages that enable the service to serve different clients and interoperate with multiple services, while permitting future growth. Additionally, clients for RESTful services generally are not difficult to develop, yielding interoperability advantages because most RESTful services use common data representations such as XML and JSON.

By using JAX-RS technology, REST applications are simpler to develop, simpler to consume, and simpler to scale when compared to other types of distributed systems. Many popular and widely used Internet services have successfully provided RESTful APIs to their applications. Third parties have used various REST APIs to build their own businesses and applications.

JAX-RS capabilities are provided by the use of a servlet or a filter. When you configure web.xml of the web application and assemble the IBM JAX-RS implementation based on the Apache Wink framework into the library directory of the web application, your business application is now ready to use JAX-RS capabilities.


Procedure

  1. Configure the development environment.

  2. Define the resources in JAX-RS web applications.

    Resources are the basic building block of a RESTful service. Resources can contain static or dynamically updated data. Examples of resources from an online book store application include a book, an order from a store, and a collection of users. By identifying the resources in the application, we can make the service more useful and easier to develop.

  3. Configure the JAX-RS application

    We can configure JAX-RS applications in multiple ways depending on your needs. To take advantage of the Java EE 6 functionality, we can use the annotation scanning capabilities. By using annotation scanning, we can omit a JAX-RS javax.ws.rs.core.Application subclass or have a minimally defined javax.ws.rs.core.Application subclass. Alternatively, we can specify the IBM JAX-RS servlet or filter to use the functionality available in the IBM JAX-RS servlet and filter.

    Using one of the JAX-RS v1.1 configuration methods, we can omit a javax.ws.rs.core.Application subclass in the application or have a javax.ws.rs.core.Application subclass that returns an empty set of classes to inform the JAX-RS runtime environment to find and use all the JAX-RS classes in the application. You might want to use this method when we do not want to have to manually add every relevant JAX-RS class to a javax.ws.rs.core.Application subclass as you develop the application.

    By specifying the specific IBM JAX-RS servlet and filter, we can take advantage of and ensure specific IBM JAX-RS behavior. For example, using the IBM JAX-RS filter can be helpful in developing a web application with a mix of JAX-RS resources and JSP files with the same URL patterns.

    Even though there is a JAX-RS V1.1 configuration method that supports the use of an optional web.xml file, to specify security constraints or roles, or to take advantage of other features enabled using a web.xml file, specify the information in a web.xml file.

    Choose one of the following three methods to configure your JAX-RS application:

  4. Assemble JAX-RS web applications.

    After you develop the Java class files for the JAX-RS web application and edit web.xml to enable the JAX-RS servlet, you are ready to assemble the application. Assemble the web application into a WAR package. We can assemble the WAR package into an EAR package, if required.

  5. Deploy JAX-RS web applications

    After we have assembled your JAX-RS web application, you need to deploy your Web archive (WAR) package or the EAR package onto the application server.


Related

Overview of IBM JAX-RS
Planning to use JAX-RS to enable RESTful services
Web services specifications and APIs


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