RESTful WS using Jersey: POST request.

POST request is used to create or update a resource by parameters provided in a form. In this tutorial, we will update the service created in the previous tutorial to handle the POST request. Instead of creating a html page with a form for a POST request, we use the form function provided by Jersey client library.

1. Open the RestResource class in the package my.third.rest in the previous tutorial.
2. Insert the following code for the POST request handling
   
   

   	  @POST
   	  @Produces(MediaType.TEXT_HTML)
   	  @Consumes(MediaType.APPLICATION_FORM_URLENCODED) //@Consumes(type[, more-types]) defines which MIME type is consumed by this method	
   	  public String postUser(@FormParam("id") String uid, @FormParam("name") String name) { //@FormParam for POST method acts as @PathParam for GET method 
   	    if (listUsers.containsKey(uid)) { 
   	    	listUsers.get(uid).setName(name);
   	    	return "The user is updated. Current list is: \n" + listOfUsersInText();
   	    }
   	    listUsers.put(uid, new User(uid, name));
   		return "The user is added. Current list is: \n" + listOfUsersInText();
   	  }

3. Correct the errors generated by Eclipse's suggestion or by inserting the following lines in the import section
   
   

   import javax.ws.rs.POST;
   import javax.ws.rs.Consumes;
   import javax.ws.rs.FormParam;

4. Copy the ClientRequest class from the my.second.rest package to my.third.rest package and modify its source code as following:
   
   

   package my.third.rest;
    
   import javax.ws.rs.client.Client;
   import javax.ws.rs.client.ClientBuilder;
   import javax.ws.rs.client.Entity;
   import javax.ws.rs.client.WebTarget;
   import javax.ws.rs.core.Form;
   import javax.ws.rs.core.MediaType;
   import javax.ws.rs.core.Response;
   import javax.ws.rs.core.UriBuilder;
    
   import org.glassfish.jersey.client.ClientConfig;
    
    
   public class ClientRequest {
     public static void main(String[] args) {
   	String HELLO_REST_URI = "http://localhost:8080/rest";
   	ClientConfig config = new ClientConfig();
   	Client client = ClientBuilder.newClient(config); 
    
   	    WebTarget target = client.target(UriBuilder.fromUri(HELLO_REST_URI)).path("users");
    
       //create a form and add to this form information of a user
       Form form = new Form();
       form.param("id", "1");	
       form.param("name", "Mary");
    
       //send this form to the server and get response
       Response response = target.request().accept(MediaType.TEXT_HTML)
       		.post(Entity.entity(form,MediaType.APPLICATION_FORM_URLENCODED));
       System.out.println(response.readEntity(String.class));
    
     }
   } 

5. Right click on this ClientRequest, select Run As→Java Application. You will get
   
   

   The user is updated. Current list is: 
   Peter
   Mary

6. If you change the id in your client request to 3 and rerun the ClientRequest application, you will get
   
   

   The user is added. Current list is: 
   Mary
   Peter
   John