Sample JAX-RS REST API Implementation

 We can use different  tools and technologies to create and expose a REST API. In this blog I will explain how to create a simple JAX-RS REST API using JDeveloper. 

• Open Jdeveloper and create a new ADF REST Web Application
• Provide an application name - JaxRsSampleApp
• Provide a package name - xxvk.svn
• Select Next and Keep the default Project Name 
• Select Finish
• This will generate two projects. 
• RESTModel
• RESTWebservice
• Delete the RESTModel project
• Right click the RESTWebservice project and select new
• Select Java Class and provide a name. - HelloService
• Add following  @Path("/services") before the class definition // Note : Path can be anything
• Select the warning/error next to Path and select add JaxRs package to the project. 
• As soon as you add the JAX RS package to the project it will generate the main application Java class - GenericApplication with an extend jax.rs.core.Application
• Delete the default method and add the following sample method to return sample plain text. 
• Right click the project and select project properties
• Got to Java EE Application
• Context Root to a meaning full value. -- HelloService
• Save changes 
• Right click the Java service and select RUN. 
• This will deploy the application to Integrated server and provide the sample URL
• http://127.0.0.1:7101/xxvk-service/resources/services
• Take the URL and paste in a browser. It will display the result. 

    package xxvk.svn;

    import javax.ws.rs.GET;

    import javax.ws.rs.Path;

    import javax.ws.rs.Produces;

    import javax.ws.rs.core.MediaType;

@Path("/services")

public class HelloService {

        @GET  // This will import the Get package

        @Produces(MediaType.TEXT_PLAIN)  // This will produce the out put in plain text format
        public String Sayhello(){
            return "Hello Welcome";
        }

}

SOA - Receive Message From EJB

 We can use EJB service to receive message from locally deployed EJB applications. We can use the following steps to create a SOA application to consume message from an EJB.

• Create a SOA application 
• Create an empty SOA project
• Select the SOA project created above , right click and select New option 
• Select Java class and provide class name and package name and select ok
• If you get a prompt to select the folder then select project_name/src folder
• Overwrite the generated class with below sample interface code. 

        package svn.com.callback;
        import java.util.List;
        import svn.com.model.XxComStatus;  // POJO class representing incoming message structure.
        public interface class_name
            {
              public String exec(XxComStatus status);
            }

• Go to SOA composite add select EJB service
• Provide Service Name - ConsumeEJBMessage
• Provide a meaningful JNDI Name - ConumeCallbackMessageEJB
• Provide Java Interface Name as - svn.com.callback.class_name  // Taken from above Java code. 
• Open the composite SOURCE tab and add the missing values. 

  <service name="ConsumeEJBMessage">

    <interface.java interface="svn.com.callback.class_name"/>

    <binding.ejb uri="ConumeCallbackMessageEJB" ejb-version="EJB3" javaInterface="svn.com.callback.class_name"/>

  </service>

• Create a BPEL process without service definition
• Now wire EJB service and BPEL. This will generate the service WSDL
• Now you can update the SOA composite as per the business requirement. 

Sample Composite:

Reference : https://technology.amis.nl/it/publish-soa-composite-application-as-ejb-to-be-invoked-from-java-applications-using-ejb-binding/