问如何在Java语言中从RESTFul服务请求GET to Ipstack API

EN

public Users newUser(String username, String email) {
    Client cliente = ClientBuilder.newClient();
    WebTarget servicio = cliente.target(MONGODB + MONGOCOLL + "?apiKey=" + MONGOKEY);

    try {
        JSONObject user = new JSONObject();
        JSONObject location = new JSONObject();
        user.put("username", username);
        user.put("email", email);

        ArrayList<String> following = new ArrayList<String>();
        user.put("following", following);
        ArrayList<String> friends = new ArrayList<String>();
        user.put("friends", friends);

        String ipstackfields = "&output=json&fields=country_name,city,zip";
        Client clientipstack = ClientBuilder.newClient();
        WebTarget ipstackserv = clientipstack
                .target(IPSTACK + IPSTACKEND + "?apiKey=" + IPSTACKKEY + ipstackfields);
        Response resplocated = ipstackserv.request().get();
        String slocate = resplocated.readEntity(String.class);
        JSONObject located = new JSONObject(slocate);

        location.put("country", located.get("country_name"));
        location.put("city", located.get("city"));
        location.put("postcode", located.get("zip"));
        user.put("location", location);

        Response respuesta = servicio.request().post(Entity.json(user.toString()));

        if (respuesta.getStatus() == Status.OK.getStatusCode()) {
            // TODO: leer la respuesta de la llamada y trasformar el objeto
            // JSON a un mensaje para devolverlo
            String s = respuesta.readEntity(String.class);
            JSONObject usuario = new JSONObject(s);
            return JSONtoUser(usuario);
        } else {
            return null;
        }
    } catch (Exception e) {
        return null;
    }
}