Rest services auto scan using RestEasy + servlet 3

Question

I am planning to implement the Rest service with help of RestEasy framework (3.0.11) and servlet version 3.

I have used resteasy-scan context to scan my rest service at time of runtime, but since servlet version 3.0 hence It is not scan and throwing exception (deployed in tomcat7).

Could you please suggest me to resolve the issue, how to scan the rest services?

Any example or configuration of web.xml would be good.

Answer 1

One way, without any web.xml (RESTeasy servlet) configuration is to just have an empty Application subclass, annotated with @ApplicationPath (for the url-mapping).

According to the JAX-RS spec, in a Servlet 3.x environment if you have the following

@ApplicationPath("/api")
public class MyAppliation extends Application {

}

this is enough to cause the application to register resource class and provider through classpath scanning. In contrast, we could explicitly register resources class and providers this way

@ApplicationPath("/api")
public class MyAppliation extends Application {
    @Override
    public Set<Class<?>> getClasses() {
        Set<Class<?>> classes = new HashSet<Class<?>>();
        classes.add(MyResource.class);
        return classes;
    }
    @Override
    public Set<Object> getSingletons() {
        Set<Object> singletons = new HashSet<Object>();
        singletons.add(new MyFilter());
        return singletons;
    }
}

According to the spec, once we return a non-empty set from either one of these overridden methods, it is assumed the application takes care of all the registration, and the classpath registration is disabled.

Now this is not what you want, but it is just a background as to why the empty class works.