/** @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
HttpSession session = request.getSession();
String url = "/displayProducts.jsp";
String category = request.getParameter("category");
String sessionCategory = (String) session.getAttribute("productCategory");
if (request.getParameter("category") == null
&& session.getAttribute("productCategory") == null) {
// start up case or user did not make a selection return all categories
// get the entire list of products from database by setting category to "All"
List<DemoProductInfo> allProducts = DemoProductInfoDB.getProductsByCategory("All");
// populate the applications images file directory on server
populateImagesFromDatabase(request, response, allProducts);
// post entire list to session variable for retrieval in displayProducts screen
request.setAttribute("products", allProducts);
session.setAttribute("productCategory", "All");
if (session.getAttribute("productCategories")
== null) // load the product categories session variable
session.setAttribute("productCategories", DemoProductInfoDB.getEagerProductCategories());
} else if (request.getParameter("category") == null
&& session.getAttribute("productCategory") != null) {
// the user has previously selected a category so return filtered list of products
category = sessionCategory;
List<DemoProductInfo> products = DemoProductInfoDB.getProductsByCategory(category);
// post filtered list to session variable for retrieval in displayProducts screen
request.setAttribute("products", products);
// request.setAttribute("productCategory", category); // not needed as selection has not
// changed
} else if (request.getParameter("category") != null) {
// user has made a selection or selection was persisted from previous setting
List<DemoProductInfo> products = DemoProductInfoDB.getProductsByCategory(category);
// post filtered list to session variable for retrieval in displayProducts screen
request.setAttribute("products", products);
session.setAttribute("productCategory", category);
}
getServletContext().getRequestDispatcher(url).forward(request, response);
}
public int populateImagesFromDatabase(
HttpServletRequest request, HttpServletResponse response, List<DemoProductInfo> products)
throws ServletException, IOException {
final String IMAGE_DIRECTORY = "img";
final int THRESHOLD_SIZE = 1024 * 1024 * 3; // 3MB
final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB
final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB
// set variables to provide path names and scope visibility through method
String fileName = null;
int numFilesWritten = 0;
// configures file writing settings
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(THRESHOLD_SIZE);
// use factory to provide thread-safe retrieval mechanism to
// write to eventual application directory
factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setFileSizeMax(MAX_FILE_SIZE);
upload.setSizeMax(MAX_REQUEST_SIZE);
// constructs the directory path to store upload file
String uploadPath = getServletContext().getRealPath("") + File.separator + IMAGE_DIRECTORY;
// in this case use a predetermined path set at start of method
// String uploadPath = uploadToDirPath;
// creates the directory if it does not exist
File uploadDir = new File(uploadPath);
if (!uploadDir.exists()) {
uploadDir.mkdir();
}
for (DemoProductInfo product : products) {
String filePath = uploadPath + File.separator + product.getFilename();
DemoProductInfoDB.getBytesToFile(product.getProductImage(), filePath);
numFilesWritten++;
}
return numFilesWritten;
}