Correction exercice 2

public void hello2(RoutingContext ctx) {
    int id = Integer.parseInt(ctx.pathParam("id"));
    Person p = db.getPersonById(id);

    if (p == null) {
        ctx.response().setStatusCode(404);
        ctx.end("Personne introuvable");
    }
    else {
        ctx.end("Hello " + p.getFirstname());
    }
}