shoppingservlet.java

J2EE－电子商店例程

import java.util.*;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import shopping.CD;
public class ShoppingServlet extends HttpServlet {
	public void init(ServletConfig conf) throws ServletException {
		super.init(conf);
	}
	public void doPost (HttpServletRequest req, HttpServletResponse res)
	throws ServletException, IOException 
	{
		HttpSession session = req.getSession(false);
		if (session == null) 
		{
			res.sendRedirect("http://localhost:7001/Eshop/error.html");
		}
		Vector buylist=(Vector)session.getValue("shopping.shoppingcart");
		String action = req.getParameter("action");
		if (!action.equals("CHECKOUT")) 
		{
			if (action.equals("DELETE")) 
			{
				String del = req.getParameter("delindex");
				int d = (new Integer(del)).intValue();
				buylist.removeElementAt(d);
			} 
			else if (action.equals("ADD")) 
			{
			//any previous buys of same cd?
				boolean match=false;
				CD aCD = getCD(req);
				if (buylist==null) 
				{
					//add first cd to the cart
					buylist = new Vector(); //first order
					buylist.addElement(aCD);
				}
				 else 
				{ // not first buy
					for (int i=0; i< buylist.size(); i++) 
					{
						CD cd = (CD) buylist.elementAt(i);
						if (cd.getAlbum().equals(aCD.getAlbum())) 
						{
							cd.setQuantity(cd.getQuantity()+aCD.getQuantity());
							buylist.setElementAt(cd,i);
							match = true;
						} //end of if name matches
					} // end of for
					if (!match) buylist.addElement(aCD);
				}
			}
		
			session.putValue("shopping.shoppingcart", buylist);
			String url="/Eshop/EShop.jsp";
			ServletContext sc = getServletContext();
			RequestDispatcher rd = sc.getRequestDispatcher(url);
			rd.forward(req, res);
		} 
		else if (action.equals("CHECKOUT")) 
		{
			float total =0;
			for (int i=0; i< buylist.size();i++) 
			{
				CD anOrder = (CD) buylist.elementAt(i);
				float price= anOrder.getPrice();
				int qty = anOrder.getQuantity();
				total += (price * qty);
				}
			total += 0.005;
			String amount = new Float(total).toString();
			int n = amount.indexOf('.');
			amount = amount.substring(0,n+3);
			req.setAttribute("amount",amount);
			String url="/Eshop/Checkout.jsp";
			ServletContext sc = getServletContext();
			RequestDispatcher rd = sc.getRequestDispatcher(url);
			rd.forward(req,res);
		}
	}
	
	private CD getCD(HttpServletRequest req) 
	{
		//imagine if all this was in a scriptlet...ugly, eh?
		String myCd = req.getParameter("CD");
		String qty = req.getParameter("qty");
		StringTokenizer t = new StringTokenizer(myCd,"|");
		String album= t.nextToken();
		String artist = t.nextToken();
		String country = t.nextToken();
		String price = t.nextToken();
		price = price.replace('$',' ').trim();
		CD cd = new CD();
		cd.setAlbum(album);
		cd.setArtist(artist);
		cd.setCountry(country);
		cd.setPrice((new Float(price)).floatValue());
		cd.setQuantity((new Integer(qty)).intValue());
		return cd;
	}
}