Facebook OAuth with Scribe in Struts 1

Authenticate.java

import org.apache.struts.action.*;
import com.google.gson.*;
import org.scribe.builder.*;
import org.scribe.builder.api.*;
import org.scribe.model.*;
import org.scribe.oauth.*;

public class Authenticate extends Action {

  public ActionForward execute(ActionMapping mapping, ActionForm form,
      HttpServletRequest request, HttpServletResponse response)
      throws Exception {

    OAuthService service = new ServiceBuilder()
                               .provider(FacebookApi.class)
                               .apiKey(Facebook.client_id)
                               .apiSecret(Facebook.client_secret)
                               .callback(Facebook.redirect_uri)
                               .build();

    String verifierCode = request.getParameter("code");
    if(verifierCode == null) {
      String authURL = service.getAuthorizationUrl(null);
      return new ActionForward(authURL, true);
    }
    else {
      Token accessToken = service.getAccessToken((Token)null, new Verifier(verifierCode));
      OAuthRequest authRequest = new OAuthRequest(Verb.GET, "https://graph.facebook.com/me");
      service.signRequest(accessToken, authRequest);
      Response authResponse = authRequest.send();

      JsonParser parser = new JsonParser();
      JsonObject authData = parser.parse(authResponse.getBody()).getAsJsonObject();
      request.setAttribute("facebookId",authData.getAsJsonPrimitive("id").getAsString());

      return mapping.findForward(...);
    }
  }
}

More details at http://www.philihp.com/blog/2012/authenticating-to-facebook-in-struts-1-with-scribe-and-gson/