How to create shopping cart and store multiple items in it using servlets and session tracking

[Jeff Numo]

I have only just started learning about servlets, java and JDBC stuff and would like some help on creating a shopping cart that does the following:

1. Can add multiple items to the shopping cart, so it doesn't wipe the shopping cart once you leave that page or add another item to it.
2. Display the total price of all the items that has been added to the shopping cart.
3. Have an option for the user to remove an item from the cart.

The thing I don't understand is how to store multiple items using some sort of session tracking since I have never learnt it before.

Any help would be appreciated and thank you in advance.

Here is my code:

try{
        String selectSQL = "select * from items_table where item_name = '"+item+"'";

        Statement stmt = conn.createStatement();
        ResultSet rs1 = stmt.executeQuery(selectSQL);



        // Retrieve the results

        out.println("<table border=\"1\"><tr><th>Item_ID</th><th>Item_name</th><th>Title</th><th>Category</th><th>Price</th><th>Add to Cart</th></tr>");
        if(rs1.next()){
        out.println("<form action=\"ChildServlet\">");
        out.println("<tr><td>"+ rs1.getFloat("item_id") + "</td>");
        out.println("<td>" + rs1.getString("item_name") + "</td>"); 
        out.println("<td>" +"<a href ='" + request.getContextPath() +"/ItemDetail?id="+rs1.getFloat("item_id")+ "'>"+ rs1.getString("title")+"</a>" + "</td>");
        out.println("<td>" + rs1.getString("category") + "</td>");
        out.println("<td> " + rs1.getFloat("price") + "</td>");
        out.println("<td>");
        out.println("<input type=\"hidden\" name=\"item_id\" value='"+ rs1.getFloat("item_id") +"'>");
        out.println("<input type=\"hidden\" name=\"name\" value='"+ rs1.getString("item_name") +"'>");
        out.println("<input type=\"hidden\" name=\"title\" value='"+ rs1.getString("title") +"'>");
        out.println("<input type=\"hidden\" name=\"price\" value='"+ rs1.getFloat("price") +"'>");

        out.println("<input type=\"submit\" value=\"Add to cart\" >");
        out.println("</form>");
        out.println("</td>");
        out.println("</tr>");



        }
        else 
        if(!rs1.next()){
        out.println("Error");
        response.sendRedirect("error.html");

        }

And my attempt at making a shopping cart:

 String id = request.getParameter("item_id");
    String name = request.getParameter("name");
    String title = request.getParameter("title");
    String price = request.getParameter("price");





    out.println("<table border=\"1\"><tr><th>Item_ID</th><th>Item_name</th><th>Title</th><th>Price</th></tr>");

        out.println("<tr><td> "+ id + "</td>");
        out.println("<td>" + name + "</td>"); 
        out.println("<td>" + title + "</td>");
        out.println("<td> " + price + "</td>");

        out.println("</tr>");

[Bear Bibeault]

You should not be creating your HTML view inside strings inside Java code. That's what a JSP is for. Please read this article for information on how to properly structure Java web applications.