Thread: Implement paging when having an underlying servlet controller

Here is the jsp code :

<table id="productTable">
 
        <c:forEach var="product" items="${categoryProducts}" varStatus="iter">
 
            <tr class="${((iter.index % 2) == 0) ? 'lightBlue' : 'white'}">
                <td>
                    <img src="${initParam.productImagePath}${product.name}.png"
                         alt="${product.name}">
                </td>
 
                <td>
                    ${product.name}
                    <br>
                    <span class="smallText">${product.description}</span>
                </td>
 
                <td>&euro; ${product.price}</td>
 
                <td>
                    <form action="addToCart" method="post">
                        <input type="hidden"
                               name="productId"
                               value="${product.id}">
                        <input type="submit"
                               name="submit"
                               value="add to cart">
                    </form>
                </td>
            </tr>
 
        </c:forEach>
 
    </table>

and here is the underlying controller servlet :

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
 
package controller;
 
import cart.ShoppingCart;
import entity.Category;
import entity.Product;
import java.io.IOException;
import java.util.Collection;
import java.util.Map;
import javax.ejb.EJB;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import session.CategoryFacade;
import session.OrderManager;
import session.ProductFacade;
import validate.Validator;
 
/**
 *
 * @author tgiunipero
 */
@WebServlet(name = "Controller",
            loadOnStartup = 1,
            urlPatterns = {"/category",
                           "/addToCart",
                           "/viewCart",
                           "/updateCart",
                           "/checkout",
                           "/purchase",
                           "/chooseLanguage"})
public class ControllerServlet extends HttpServlet {
 
    private String surcharge;
 
    @EJB
    private CategoryFacade categoryFacade;
    @EJB
    private ProductFacade productFacade;
    @EJB
    private OrderManager orderManager;
 
    @Override
    public void init(ServletConfig servletConfig) throws ServletException {
 
        super.init(servletConfig);
 
        // initialize servlet with configuration information
        surcharge = servletConfig.getServletContext().getInitParameter("deliverySurcharge");
 
        // store category list in servlet context
        getServletContext().setAttribute("categories", categoryFacade.findAll());
    }
 
    /**
     * Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
 
        String userPath = request.getServletPath();
        HttpSession session = request.getSession();
        Category selectedCategory;
        Collection<Product> categoryProducts;
 
        // if category page is requested
        if (userPath.equals("/category")) {
 
            // get categoryId from request
            String categoryId = request.getQueryString();
 
            if (categoryId != null) {
 
                // get selected category
                selectedCategory = categoryFacade.find(Short.parseShort(categoryId));
 
                // place selected category in session scope
                session.setAttribute("selectedCategory", selectedCategory);
 
                // get all products for selected category
                categoryProducts = selectedCategory.getProductCollection();
 
                // place category products in session scope
                session.setAttribute("categoryProducts", categoryProducts);
            }
 
 
        // if cart page is requested
        } else if (userPath.equals("/viewCart")) {
 
            String clear = request.getParameter("clear");
 
            if ((clear != null) && clear.equals("true")) {
 
                ShoppingCart cart = (ShoppingCart) session.getAttribute("cart");
                cart.clear();
            }
 
            userPath = "/cart";
 
 
        // if checkout page is requested
        } else if (userPath.equals("/checkout")) {
 
            ShoppingCart cart = (ShoppingCart) session.getAttribute("cart");
 
            // calculate total
            cart.calculateTotal(surcharge);
 
            // forward to checkout page and switch to a secure channel
 
 
        // if user switches language
        } else if (userPath.equals("/chooseLanguage")) {
            // TODO: Implement language request
 
        }
 
        // use RequestDispatcher to forward request internally
        String url = "/WEB-INF/view" + userPath + ".jsp";
 
        try {
            request.getRequestDispatcher(url).forward(request, response);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
 
 
    /**
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
 
        String userPath = request.getServletPath();
        HttpSession session = request.getSession();
        ShoppingCart cart = (ShoppingCart) session.getAttribute("cart");
        Validator validator = new Validator();
 
        // if addToCart action is called
        if (userPath.equals("/addToCart")) {
 
            // if user is adding item to cart for first time
            // create cart object and attach it to user session
            if (cart == null) {
 
                cart = new ShoppingCart();
                session.setAttribute("cart", cart);
            }
 
            // get user input from request
            String productId = request.getParameter("productId");
 
            if (!productId.isEmpty()) {
 
                Product product = productFacade.find(Integer.parseInt(productId));
                cart.addItem(product);
            }
 
            userPath = "/category";
 
 
        // if updateCart action is called
        } else if (userPath.equals("/updateCart")) {
 
            // get input from request
            String productId = request.getParameter("productId");
            String quantity = request.getParameter("quantity");
 
            boolean invalidEntry = validator.validateQuantity(productId, quantity);
 
            if (!invalidEntry)
            {
                Product product = productFacade.find(Integer.parseInt(productId));
                cart.update(product, quantity);
            }
 
            userPath = "/cart";
 
 
        // if purchase action is called
        } else if (userPath.equals("/purchase")) {
            //Implement purchase action
            if (cart != null)
            {
                //extract user data from request
                String name = request.getParameter("name");
                String email = request.getParameter("email");
                String phone = request.getParameter("phone");
                String address = request.getParameter("address");
                String cityRegion = request.getParameter("cityRegion");
                String ccNumber = request.getParameter("creditcard");
 
                //validate user data
                boolean validationErrorFlag = false;
                validationErrorFlag = validator.validateForm(name, email, phone, address, cityRegion, ccNumber, request);
 
                //if validation error found, return user to checkout
                if (validationErrorFlag == true)
                {
                    request.setAttribute("validationErrorFlag", validationErrorFlag);
                    userPath = "/checkout";
                }
                else    //otherwise, save order to database
                    {
 
                    int orderId = orderManager.placeOrder(name, email, phone, address, cityRegion, ccNumber, cart);
 
                        //if order processed successfully send user to confirmation page
                        if (orderId != 0)
                        {
                            //dissociate shopping cart from session
                            cart = null;
 
                            //end session
                            session.invalidate();
 
                            //get order details
                            Map orderMap = orderManager.getOrderDetails(orderId);
 
                            //place order details in request scope
                            request.setAttribute("customer", orderMap.get("customer"));
                            request.setAttribute("products", orderMap.get("products"));
                            request.setAttribute("orderRecord", orderMap.get("orderRecord"));
                            request.setAttribute("orderedProducts", orderMap.get("orderedProducts"));
 
                            userPath = "/confirmation";
                        }
                        else //otherwise, send back to checkout page and display error
                            {
                                userPath = "/checkout";
                                request.setAttribute("orderFailureFlag", true);
                            }
                    }
            }
 
        }
 
        // use RequestDispatcher to forward request internally
        String url = "/WEB-INF/view" + userPath + ".jsp";
 
        try {
            request.getRequestDispatcher(url).forward(request, response);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
 
}

How can I add paging to this page?
Thank you.