Writing the JAX-RS Class

The first step, let us write a simple echo service using JAX-RS:

package testpackage;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.core.Response;

@Path("/echo")
public class Echo {
    @GET
    @Path("/{message}")
    public Response echoService(@PathParam("message") String message){
        return Response.status(200).entity(message).build();
    }
}

Adding the JBoss RESTEasy dependency to Maven project

If you are using Maven to build your projects, add the dependency for RESTEasy:

<dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>resteasy-jaxrs</artifactId>
    <version>1.0.0.GA</version>
</dependency>

Also remember to add the JBoss repository to the pom.xml (RESTEasy is not available in Maven public repository):

<repository>
    <id>jboss</id>
    <url>http://repository.jboss.com/maven2/</url>
    <releases>
        <enabled>true</enabled>
    </releases>
    <snapshots>
        <enabled>false</enabled>
    </snapshots>
</repository>

Configuring web.xml

The bare minimum needed to have RESTEasy running is:

<web-app ...>
    ...
    <listener>
        <listener-class>org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap</listener-class>
    </listener>

    <servlet>
        <servlet-name>Resteasy</servlet-name>
        <servlet-class>org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>Resteasy</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>
    ...
</web-app>

Above, we have just added the RESTEasy servlet and listener. Now we have to make it load our JAX-RS class. This can be done in two ways. One, just let RESTEasy scan the CLASSPATH to identify and load JAX-RS resources:

<web-app ...>
    ...
    <context-param>
        <param-name>resteasy.scan</param-name>
        <param-value>true</param-value>
    </context-param>
    ...
</web-app>

The other option is to specify the resources manually (use CSV format):

<web-app ...>
    ...
    <context-param>
        <param-name>resteasy.resources</param-name>
        <param-value>testpackage.Echo</param-value>
    </context-param>
    ...
</web-app>

After deploying this, you may access your application (if your are using default Tomcat/Jetty installation): http://localhost:8080/resteasytest/echo/hello,world (assumes your application is deployed as resteasytest.war)