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

Use multipart content in JAX-RS application requests and responses

Using multipart messages, servers and clients can transmit multiple messages using a single message. Multipart messages are useful when both the client and server need to send multiple requests but want to save the cost of sending and receiving entire HTTP request and responses for each part.

Multipart messages require special message formatting to send content for multiple messages content in a single message. IBM JAX-RS provides classes to represent the multipart data model that can help read and write multipart messages. System registered default JAX-RS entity providers can serialize and deserialize the classes into message bodies. We can instantiate one of the multipart classes and add individual parts to the multipart data model. We can then return the multipart instance in a resource method and have the JAX-RS runtime environment automatically format and output the multipart message.

If you specifically need to use multipart/form-data content, refer to the "Using multipart/form-data content in JAX-RS application requests and responses" section.

1. Configure the development environment.
   • Set up a development environment for JAX-RS applications
     
   • Development and assembly tools
     
   • Directory conventions
     

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.

   • Define the resources in RESTful applications
     
   • Define the URI patterns for resources in RESTful applications
     
   • Define resource methods for RESTful applications
     
   • Define the HTTP headers and response codes for RESTful applications
     
   • Define media types for resources in RESTful applications
     
   • Define parameters for request representations to resources in RESTful applications
     
   • Define exception mappers for resource exceptions and errors
     

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:

   • Configure JAX-RS applications using JAX-RS 1.1 methods
   • Configure web.xml for JAX-RS servlets
   • Configure web.xml for JAX-RS filters

4. Implement a resource using multipart messages

   Multi-part messages contain multiple content types in a single message. Using IBM JAX-RS, we can produce and consume multipart messages.

5. 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.

   • Assemble JAX-RS web applications
     
   • Development and assembly tools
     

6. 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

Implement resources using multipart messages
Use multipart/form-data content in JAX-RS application requests and responses

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