Fuse ESB - Developing RESTful Web Services

Introduction

Overview

RESTful Web services implemented using JAX-RS APIs provide responses as representations of a resource implemented by Java classes. A resource class is a class that uses JAX-RS annotations to implement a resource. For most RESTful Web services, there is a collection of resources that need to be accessed. The resource class' annotations provide information such as the URI of the resources and which HTTP verb each operation handles.

Types of resources

The JAX-RS APIs allow you to create two basic types of resources:

A root resource class is the entry point to a service's resource tree. It is decorated with the @Path annotation to define the base URI for the resources in the service.
Sub-resources are accessed through the root resource. They are implemented by methods that are decorated with the @Path annotation. A sub-resource's @Path annotation defines a URI relative to the base URI of a root resource.

Example

Example 1 shows a simple resource class.

Example 1. Simple resource class

package demo.jaxrs.server;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;

@Path("/customerservice") 
public class CustomerService
{
  public CustomerService()
  {
  }

  @GET 
  public Customer getCustomer(@QueryParam("id") String id)
  {
    ...
  }

  ...
}

Two items make the class defined in Example 1 a resource class:

	The `@Path` annotation specifies the base URI for the resource.
	The `@GET` annotation specifies that the method implements the HTTP `GET` method for the resource.

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