Guice - Jersey - Servlet binding

Question

I recently switched to two phase injection and this has created an error in my servlet binding. I am currently toggling between two error modes and not sure which direction is best to pursue.

The first error I encountered was:

com.sun.jersey.api.container.ContainerException: The ResourceConfig instance does not contain any root resource classes.

My servlet module looked like this:

public class MyServletModule extends JerseyServletModule {
    @Override
    protected void configureServlets() {
        bind(MyServlet.class).asEagerSingleton();

        serve("/*").with(GuiceContainer.class);
    }
}

I was able to remove this error by explicitly providing the com.sun.jersey.config.property.packages parameter.

public class MyServletModule extends JerseyServletModule {

    @Override
    protected void configureServlets() {
        bind(MyServlet.class).asEagerSingleton();

        Map<String,String> parameters = new HashMap<String, String>();
        parameters.put(PackagesResourceConfig.PROPERTY_PACKAGES, MyServlet.class.getPackage().getName());
        serve("/*").with(GuiceContainer.class, parameters);
    }
}

But when I do this, Guice attempts a Just in Time binding which does not respect the @Inject on my servlet constructor.

com.google.inject.ConfigurationException: Guice configuration errors:

1) Unable to create binding for MyServlet. It was already configured on one or more child injectors or private modules bound at MyServletModule.configureServlets(MyServletModule.java:44) If it was in a PrivateModule, did you forget to expose the binding? while locating MyServlet

1 error at com.google.inject.internal.InjectorImpl.getBinding(InjectorImpl.java:150)

My servlet has an @Inject constructor who's arguments cannot be bound just in time. After debugging into InjectorImpl, I believe this is the reason that things fail when I use PROPERTY_PACKAGES.

I'm just not sure if using PROPERTY_PACKAGES is correct and I need to fix some bindings? Or if that is the wrong direction and I need to fix the original ResourceConfig error in a different way.

Help or a push in the right direction is appreciated.

Answer 1

I was able to bind Jersey resources to Guice without using the bind-parameters (without explicitly providing the com.sun.jersey.config.property.packages parameter), by binding resources separately

public class BindJerseyResources extends ServletModule {

    @Override
    protected void configureServlets() {
        // excplictly bind GuiceContainer before binding Jersey resources
        // otherwise resource won't be available for GuiceContainer
        // when using two-phased injection
        bind(GuiceContainer.class);

        // bind Jersey resources
        PackagesResourceConfig resourceConfig = new PackagesResourceConfig("jersey.resources.package");
        for (Class<?> resource : resourceConfig.getClasses()) {
            bind(resource);
        }

        // Serve resources with Jerseys GuiceContainer
        serve("/*").with(GuiceContainer.class);
    }
}

The resources are like following

@Path("/")
@RequestScoped
public class Resource {

    private Storage storage;

    @Inject
    public Resource(Storage storage) {
        this.storage = storage;
    }

    @GET
    @Path("get/{name}")
    @Produces(MediaType.TEXT_PLAIN)
    public String getGuid(@PathParam("name") String name) {
        return storage.get(name);
    }
}

Maybe this helps you to avoid the latter problematic binding.

---

Updated the answer to work with two-phased injection.