How to create a simple CXF based JAX-RS Client

 

In my previous blog post, I did explain how to create a REST API using CXF and Spring.

This time I would like to describe how to quickly create a client that can call the REST API while reusing the resources POJO classes,
so the un-marshalling is done by JAXB.

For this I am using the CXF WebClient which is very simple to use:

• import WebClient from org.apache.cxf.jaxrs.client.WebClient
• import your POJOs
• import a JABX provider (I am using Jackson JAXB JSON provider)

 Here is a very simple standalone program that does exactly this (make sure your REST API has been deployed locally):

 
import com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider;
import org.apache.cxf.jaxrs.client.WebClient;
import java.util.ArrayList;
import java.util.List;

public class App 
{
    public static void main( String[] args )  throws Exception { 
      
     List<Object> providers = new ArrayList<Object>();
     providers.add( new JacksonJaxbJsonProvider() );
   
     WebClient client = WebClient.create("http://localhost:8080/poc_restapi_cxf/api", providers);
     client = client.accept("application/json").type("application/json").path("/order").query("id", "1");
   
     Order order = client.get(Order.class);
     System.out.println("Order:" + order.getCustomerName());
  
    }
}

With this very simple client program, the response to your request (JSON) is automatically unmarshalled to a Java object. 

If you are using maven, make sure you have the correct dependencies in your pom file:

    <dependency>
       <groupId>org.apache.cxf</groupId>
       <artifactId>cxf-rt-transports-http</artifactId>
       <version>${cxf.version}</version>
       <scope>provided</scope>
    </dependency>
   
    <dependency>
       <groupId>org.apache.cxf</groupId>
       <artifactId>cxf-rt-rs-extension-search</artifactId>
       <version>${cxf.version}</version>
       <scope>provided</scope>
    </dependency>
     
    <dependency>
       <groupId>org.apache.cxf</groupId>
       <artifactId>cxf-rt-rs-extension-providers</artifactId>
       <version>${cxf.version}</version>
       <scope>provided</scope>
    </dependency>
      
    <dependency>
    <groupId>com.fasterxml.jackson.jaxrs</groupId>
       <artifactId>jackson-jaxrs-json-provider</artifactId>
       <version>2.0.2</version>
    </dependency> 

REST-Style Architecture and the Development of Mobile Health Care Applications

Mobile devices offer new ways for users to access health care data and services in a secure and user-friendly environment. These new applications must be easy to create, deploy, test and maintain, and they must rely on a scalable and easily integrated infrastructure.

In the ambulatory health care environment, providers spend the majority of their time in an examination room with patients. Although some clinics have installed personal computers in the exam room for use at the point of care, many physician practices have yet to do so or have no such intention. Reasons for not installing PCs in the exam room include (among others) lack of space, security concerns, and cost. Often, clinics have PCs installed outside of the exam room to be used for encounter documentation or health history research (i.e., reviewing the patient's health records). This physical setup is often satisfactory for providers to complete their documentation needs. Providers often scratch rough notes on paper during an encounter, then dictate or type their notes after the visit has ended. The absence of computers in the exam room, however, is a disadvantage for research activities. Frequently, after listening to the patient's verbal health history, a provider wishes to read past records. If those records are in an electronic format, it is optimal to access those records at the point of care (i.e., in the exam room).

Thus, computer devices that are smaller and more mobile than a PC (e.g., smart phones, PDAs, tablets) would be the optimal hardware choice to access these electronic records. Given that many physicians carry smart phones, such mobile devices would be the ultimate tools to look up patient records.

Since the development of client applications on different mobile platforms requires more time than creating web applications for a handful of browsers, it is important to minimize the complexity of the integration with the back-end services and legacy systems and to try to decouple the development and maintenance of the client- and server-side components.

The Representational State Transfer (REST) architecture is an alternative to SOAP and offers clear advantages over SOAP including lightweight architecture, extensibility, scalability, easy of development, testing, deployment and maintenance.

REST API prototypes can be created in a matter of days and a full functioning set of sophisticated clinical based web services accessible by mobile client applications within few weeks.

In addition to this, REST APIs are particularly suitable for fast and loosely-coupled solution integration such as mobile applications, but can also be used in health care for portal and mash-up applications as well.


Reference:
Andry F., Wan L., Nicholson D., A mobile application accessing patients' health records through a REST API, 4th International Conference on Health Informatics (HEALTHINF 2011), pp 27-32, Rome 2011.