在REST服务中创建Jersey客户端

Question

i am creating a http REST service that consumes other http REST services.

I am using Jersey Client to call other services and i have many doubt about which creation pattern of the http client is the best.

Currently i am using EJB with injection of the client that is a Singleton shared by every methods, but i would like to remove java ee dependency and use Jetty as embedded application server.

I see from the doc that Client creation is an expensive operation so i cannot create one every time i need it.

I think about creating 1 in the constructor of every Servlet/Rest class is the simpler solution but i am not sure about the lifecycle of the servlet (if an instance is created for every request, this method is quite the same as the previous)

Or maybe is better to create a Singleton shared by every Servlet/Rest class

Or maybe better a pool of N client.

About this last two solution i need some advice... What do you think it's the better solution?

Thanks

Answer 1

According to you, there is a REST Service deployed in some environment and there is one application, a client or consumer , which wants to access that service.

If i am writing a normal Java class as client using Jersey API, then i will write something lime this :

import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;

Client client = Client.create(); 
WebResource webResource = client
       .resource("http://localhost:8080/rest/example/employees");

ClientResponse response = webResource.accept("application/json")
               .get(ClientResponse.class);
String result = response.getEntity(String.class);

Now say you are writing a servlet , which does some defined job in you application, also it makes a call to the REST Service using client block of code, everytime you access the servlet it will create a instance of com.sun.jersey.api.client.Client each time.

If you want to avoid this then you can create a initial class that will create an instance of com.sun.jersey.api.client.Client , one and only, and make it static and use the same reference where ever you want. WebResource should be created as and when required, because you might be interested to call different URIs .

I would have followed this approach, if i were in your situation.