I am trying to convert some of this servlet into JSP presentation layer.
I would appreciate for any feedback.
Thanks.
Better (same) version of this code is located at:
http://volume1.coreservlets.com/archive/coreservlets/OrderPage.java
----------------------------------------------------------------------------------------
package coreservlets;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.text.*;
/** Shows all items currently in ShoppingCart. Clients
* have their own session that keeps track of which
* ShoppingCart is theirs. If this is their first visit
* to the order page, a new shopping cart is created.
* Usually, people come to this page by way of a page
* showing catalog entries, so this page adds an additional
* item to the shopping cart. But users can also
* bookmark this page, access it from their history list,
* or be sent back to it by clicking on the "Update Order"
* button after changing the number of items ordered.
* <P>
* Taken from Core Servlets and JavaServer Pages 2nd Edition
* from Prentice Hall and Sun Microsystems Press,
* http://www.coreservlets.com/.
* © 2003 Marty Hall; may be freely used or adapted.
*/
public class OrderPage extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
HttpSession session = request.getSession();
ShoppingCart cart;
synchronized(session) {
cart = (ShoppingCart)session.getAttribute("shoppingCart");
// New visitors get a fresh shopping cart.
// Previous visitors keep using their existing cart.
if (cart == null) {
cart = new ShoppingCart();
session.setAttribute("shoppingCart", cart);
}
String itemID = request.getParameter("itemID");
if (itemID != null) {
String numItemsString =
request.getParameter("numItems");
if (numItemsString == null) {
// If request specified an ID but no number,
// then customers came here via an "Add Item to Cart"
// button on a catalog page.
cart.addItem(itemID);
} else {
// If request specified an ID and number, then
// customers came here via an "Update Order" button
// after changing the number of items in order.
// Note that specifying a number of 0 results
// in item being deleted from cart.
int numItems;
try {
numItems = Integer.parseInt(numItemsString);
} catch(NumberFormatException nfe) {
numItems = 1;
}
cart.setNumOrdered(itemID, numItems);
}
}
}
// Whether or not the customer changed the order, show
// order status.
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String title = "Status of Your Order";
String docType =
"<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 " +
"Transitional//EN\">\n";
out.println(docType +
"<HTML>\n" +
"<HEAD><TITLE>" + title + "</TITLE></HEAD>\n" +
"<BODY BGCOLOR=\"#FDF5E6\">\n" +
"<H1 ALIGN=\"CENTER\">" + title + "</H1>");
synchronized(session) {
List itemsOrdered = cart.getItemsOrdered();
if (itemsOrdered.size() == 0) {
out.println("<H2><I>No items in your cart...</I></H2>");
} else {
// If there is at least one item in cart, show table
// of items ordered.
out.println
("<TABLE BORDER=1 ALIGN=\"CENTER\">\n" +
"<TR BGCOLOR=\"#FFAD00\">\n" +
" <TH>Item ID<TH>Description\n" +
" <TH>Unit Cost<TH>Number<TH>Total Cost");
ItemOrder order;
// Rounds to two decimal places, inserts dollar
// sign (or other currency symbol), etc., as
// appropriate in current Locale.
NumberFormat formatter =
NumberFormat.getCurrencyInstance();
// For each entry in shopping cart, make
// table row showing ID, description, per-item
// cost, number ordered, and total cost.
// Put number ordered in textfield that user
// can change, with "Update Order" button next
// to it, which resubmits to this same page
// but specifying a different number of items.
for(int i=0; i<itemsOrdered.size(); i++) {
order = (ItemOrder)itemsOrdered.get(i);
out.println
("<TR>\n" +
" <TD>" + order.getItemID() + "\n" +
" <TD>" + order.getShortDescription() + "\n" +
" <TD>" +
formatter.format(order.getUnitCost()) + "\n" +
" <TD>" +
"<FORM>\n" + // Submit to current URL
"<INPUT TYPE=\"HIDDEN\" NAME=\"itemID\"\n" +
" VALUE=\"" + order.getItemID() + "\">\n" +
"<INPUT TYPE=\"TEXT\" NAME=\"numItems\"\n" +
" SIZE=3 VALUE=\"" +
order.getNumItems() + "\">\n" +
"<SMALL>\n" +
"<INPUT TYPE=\"SUBMIT\"\n "+
" VALUE=\"Update Order\">\n" +
"</SMALL>\n" +
"</FORM>\n" +
" <TD>" +
formatter.format(order.getTotalCost()));
}
String checkoutURL =
response.encodeURL("../Checkout.html");
// "Proceed to Checkout" button below table
out.println
("</TABLE>\n" +
"<FORM ACTION=\"" + checkoutURL + "\">\n" +
"<BIG><CENTER>\n" +
"<INPUT TYPE=\"SUBMIT\"\n" +
" VALUE=\"Proceed to Checkout\">\n" +
"</CENTER></BIG></FORM>");
}
out.println("</BODY></HTML>");
}
}
}