ServletLevel

public class ServletLevel extends HttpServlet {
    private static final long serialVersionUID = 1L;
    private LevelDAOImpl levelDAOImpl;

    public void init() {
        String jdbcURL = getServletContext().getInitParameter("jdbcURL");
        String jdbcUsername = getServletContext().getInitParameter("jdbcUsername");
        String jdbcPassword = getServletContext().getInitParameter("jdbcPassword");

        DbConnection dbConnection = new DbConnection(jdbcURL, jdbcUsername, jdbcPassword);
        levelDAOImpl= new LevelDAOImpl(dbConnection);

    }
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String action = request.getServletPath();

        try {
            switch (action) {
                case "/newL":
                    showNewForm(request, response);
                    break;
                case "/insertL":
                    insertLevel(request, response);
                    break;
                case "/deleteL":
                    deleteLevel(request, response);
                    break;
                case "/editL":
                    showEditForm(request, response);
                    break;
                case "/updateL":
                    updateLevel(request, response);
                    break;
                case "/listL":
                    listLevel(request, response);
                    break;
                default:
                    listLevel(request, response);
                    break;
            }
        } catch (SQLException ex) {
            throw new ServletException(ex);
        }
    }
    private void listLevel(HttpServletRequest request, HttpServletResponse response)
            throws SQLException, IOException, ServletException {
        List<Level> listLevel = levelDAOImpl.GetAll();
        request.getSession().setAttribute("listLevel", listLevel);
        request.getRequestDispatcher("Level.jsp").forward(request, response);

    }

    private void showNewForm(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        RequestDispatcher dispatcher = request.getRequestDispatcher("AddLevel.jsp");
        dispatcher.forward(request, response);
    }

    private void showEditForm(HttpServletRequest request, HttpServletResponse response)
            throws SQLException, ServletException, IOException {
        int id_level = Integer.parseInt(request.getParameter("id_level"));
        Level existingLevel = levelDAOImpl.getId(id_level);
        RequestDispatcher dispatcher = request.getRequestDispatcher("AddLevel.jsp");
        request.setAttribute("level", existingLevel);
        dispatcher.forward(request, response);

    }