How to map servlet and jsp in web xml file

I have a jsp web application. I want to keep jsp in separate folders like this f1/jsp1.jsp, f2/jsp21.jsp,f2/jsp22.jsp, f3/jsp3.jsp and also some servlet files directly in default package. Now if i have to call a servlet in ajax i have to go one step back like shown below(../Category). How can i avoid it. I want to call it directly(Category) and also want to keep jsp files inside folder

$.ajax({
    url: '../Category',
    data: {"category_id": id, "status": value3, "mode": button_id},
    dataType: "html",
    contentType: "application/json",
    type: 'GET',
    success: function () {
        if (status === "Active") {
            swal({title: "Deactivated!", text: "De-activated the course category successfully.", type: "success"},
                    function () {
                        //  $('#sampleTable').load(location.href+"#sampleTable");
                        location.reload();
                    });
        } else {
            swal({title: "Activated!", text: "Activated the course category successfully.", type: "success"},
                    function () {
                        //     $('#sampleTable').load(location.href+"#sampleTable");
                        location.reload();
                    });
        }
    },
    error: function () {
        swal("Error", "System Error: Could not " + value2 + " the category in the database. Please try again or report to the system admin.", "error");
    }
});