import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ShoppingCart extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
doPost(request, response);
}
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("Widget Inc."+
"Widget Inc. Online Shopping
");
HttpSession session = request.getSession();
Map cart;
if (session.isNew()) {
cart = new TreeMap();
session.setAttribute("cart", cart);
} else
cart = (Map)session.getAttribute("cart");
if (request.getMethod().equals("POST")) {
String item = request.getParameter("item");
String amount = request.getParameter("amount");
if (item!=null)
try {
addToCart(cart, item, Integer.parseInt(amount));
} catch (Exception e) {
response.sendError(response.SC_BAD_REQUEST,
"malformed request");
}
}
String url = request.getRequestURI();
out.println("");
if (cart.isEmpty())
out.println("Your shopping cart is empty.");
else {
out.println("Your shopping cart now contains:
"+
"
| Item | Amount");
Iterator i = cart.entrySet().iterator();
while (i.hasNext()) {
Map.Entry me = (Map.Entry)i.next();
out.println(" |
|---|
| "+me.getKey()+
" | "+me.getValue());
}
out.println(" |
");
out.println("
");
}
out.println("");
}
void addToCart(Map cart, String item, int amount) {
if (amount<0)
return;
Integer a = (Integer)cart.get(item);
if (a==null)
a = new Integer(0);
cart.put(item, new Integer(a.intValue()+amount));
}
}