Handling POST request with Restlet

In this tutorial, we will create a method that listens a POST request from a client and returns an appropriated message. We reuse class created in the previous tutorial. We also modify the client java class in the first tutorial to send a POST request.

1. Open the RouterApplication class in the forthREST package and add: router.attach(“/users”, UserResource.class); after creating a new router. Finally we have:
   
   

   package forthREST;
    
   import org.restlet.Application;
   import org.restlet.Restlet;
   import org.restlet.routing.Router;
    
   public class RouterApplication extends Application{
   	/**
   	 * Creates a root Restlet that will receive all incoming calls.
   	 */
   	@Override
   	public synchronized Restlet createInboundRoot() {
   		// Create a router Restlet that routes each call to a new respective instance of resource.
   		Router router = new Router(getContext());
   		// Defines only three routes
   		router.attach("/users", UserResource.class);
   		router.attach("/users/{uid}", UserResource.class);
   		router.attach("/users/{uid}/items", UserItemResource.class);
   		return router;
   	}
   }

2. Open the UserResource class and add the following codes after the @Get method
   
   

       @Post
       public Representation acceptItem(Representation entity) {  
   		Representation result = null;  
           // Parse the given representation and retrieve data
           Form form = new Form(entity);  
           String uid = form.getFirstValue("uid");  
           String uname = form.getFirstValue("uname");  
    
           if(uid.equals("123")){ // Assume that user id 123 is existed
           result = new StringRepresentation("User whose uid="+ uid +" is updated",  
               MediaType.TEXT_PLAIN);
           } 
           else { // otherwise add user  
           result = new StringRepresentation("User " + uname + " is added",  
               MediaType.TEXT_PLAIN);
           }  
    
           return result;  
       } 

3. Import the missing methods following suggestions of Eclipes. These methods are provided by the org.restlet.jar library.
4. Open the ClientCall class in the client package that we created in the first tutorial and modify it as following:
   
   

   package client;
    
   import java.io.IOException;
    
   import org.restlet.data.Form;
   import org.restlet.representation.Representation;
   import org.restlet.resource.ClientResource;
   import org.restlet.resource.ResourceException;
    
   public class ClientCall {
    
   	/**
   	 * @param args
   	 */
   	public static void main(String[] args) {
   		// TODO Auto-generated method stub
    
   		// Create the client resource  
   		ClientResource resource = new ClientResource("http://localhost:8182/users");  
    
   		Form form = new Form();  
   		form.add("uid", "1234");  
   		form.add("uname", "John");  
    
   		// Write the response entity on the console
   		try {
    
   			resource.post(form).write(System.out);
    
   		} catch (ResourceException e) {
   			// TODO Auto-generated catch block
   			e.printStackTrace();
   		} catch (IOException e) {
   			// TODO Auto-generated catch block
   			e.printStackTrace();
   		}  
   	}
    
   }

5. Save all.
6. Run the server (RESTDistributor class in the forthREST package)
7. Run the client (ClientCall class in the *client package) - Change the values of uid and uname in the form** variable to see different results.