res.setContentType("text/html");
PrintWriter out = res.getWriter();
// Get the current session object, create one if necessary.
HttpSession session = req.getSession(true);
// Cart items are maintained in the session object.
String[] items = (String[])session.getValue("cart.items");
out.println("<HTML><HEAD><TITLE>SessionTracker</TITLE></HEAD>");
out.println("<BODY><H1>Session Tracking Demo</H1>");
// 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. Encode it as necessary.
out.println("For help, click <A HREF=\"" +
res.encodeUrl("/servlet/Help?topic=ShoppingCartViewer") +
"\">here</A>");
out.println("</BODY></HTML>");
