First server

Introduction

Let’s first see how the Restlet Framework can listen to client requests and reply to them. We will use the internal Restlet HTTP server connector (even though it is possible to switch to others such as the one based on Jetty) and return a simple string representation “hello, world” as plain text. Note that the FirstServerResource class extends the base org.restlet.resource.ServerResource class provided by the Restlet API:

public class FirstServerResource extends ServerResource {  

   public static void main(String[] args) throws Exception {  
      // Create the HTTP server and listen on port 8182  
      new Server(Protocol.HTTP, 8182, FirstServerResource.class).start();  
   }

   @Get  
   public String toString() {  
      return "hello, world";  
   }

}

If you run this code and launch your server, you can open a Web browser and hit the http://localhost:8182. Actually, any URI will work, try also http://localhost:8182/test/tutorial. Note that if you test your server from a different machine, you need to replace “localhost” by either the IP address of your server or its domain name if it has one defined.

So far, we have mostly showed you the highest level of abstraction in the Restlet API, with the ServerResource classes. But as we move forward, you will discover that this class is supported by a broad Java API, mapping all REST and HTTP concepts to a set of Java classes, interfaces and annotations.

Let’s now illustrate how to use this API on the client-side.