ShoppingCartViewerCookie.java Source code

Introduction

Here is the source code for ShoppingCartViewerCookie.java
Source

import java.io.IOException;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ShoppingCartViewerCookie extends HttpServlet {

    public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
        res.setContentType("text/html");
        PrintWriter out = res.getWriter();

        String sessionid = null;
        Cookie[] cookies = req.getCookies();
        if (cookies != null) {
            for (int i = 0; i < cookies.length; i++) {
                if (cookies[i].getName().equals("sessionid")) {
                    sessionid = cookies[i].getValue();
                    break;
                }
            }
        }

        // If the session ID wasn't sent, generate one.
        // Then be sure to send it to the client with the response.
        if (sessionid == null) {
            sessionid = generateSessionId();
            Cookie c = new Cookie("sessionid", sessionid);
            res.addCookie(c);
        }

        out.println("<HEAD><TITLE>Current Shopping Cart Items</TITLE></HEAD>");
        out.println("<BODY>");

        // Cart items are associated with the session ID
        String[] items = getItemsFromCart(sessionid);

        // Print the current cart items.
        out.println("You currently have the following items in your cart:<BR>");
        if (items == null) {
            out.println("<B>None</B>");
        } else {
            out.println("<UL>");
            for (int i = 0; i < items.length; i++) {
                out.println("<LI>" + items[i]);
            }
            out.println("</UL>");
        }

        // Ask if they want to add more items or check out.
        out.println("<FORM ACTION=\"/servlet/ShoppingCart\" METHOD=POST>");
        out.println("Would you like to<BR>");
        out.println("<INPUT TYPE=SUBMIT VALUE=\" Add More Items \">");
        out.println("<INPUT TYPE=SUBMIT VALUE=\" Check Out \">");
        out.println("</FORM>");

        // Offer a help page.
        out.println("For help, click <A HREF=\"/servlet/Help" + "?topic=ShoppingCartViewerCookie\">here</A>");

        out.println("</BODY></HTML>");
    }

    private static String generateSessionId() throws UnsupportedEncodingException {
        String uid = new java.rmi.server.UID().toString(); // guaranteed unique
        return URLEncoder.encode(uid, "UTF-8"); // encode any special chars
    }

    private static String[] getItemsFromCart(String sessionid) {
        return new String[] { "a", "b" };
    }
}