How to get value from submitted button in JSP? - html

Question

Don't know a better title but here is what im trying to do.
I have the following form where which will display a list of books and after every book entry there is a remove button. The list can be any length. In order to get the book id I have set name="remove[${cartItem.bookId}]" but how do I get this value in a servlet? request.getParameter("remove") and request.getParameterValues("remove") returns null everytime.
<form method="post" action="removeBookFromCart">
<c:forEach var="cartItem" items="${sessionScope.cart.cartItems}">
<tr>
<td><c:out value="${cartItem.title}" /></td>
<td><input type="submit" name="remove[${cartItem.bookId}]" value="Remove"/></td>
</tr>
</c:forEach>
</form>

Answer 1

There are several solutions:
Use <button name="bookToRemove" value="${cartItem.bookId}" type="submit">Remove</button>. This, however, doesn't work as specified in IE6 and IE7 (at least).
Iterate through the parameters, find the one which starts with remove[, and extract the ID after that. You could use a simpler name, such as remove_${cartItem.bookId}
Create one form per cart item, instead of a global form, and use a hidden field to contain the book to remove.
The third way is probably the easiest one.
You could also use some JavaScript to initialize the value of a hidden field when a button is clicked, but this is not easier than the methods above, and requires JavaScript.

Answer 2

You have to use hidden parameters:
<input type="hidden" name="remove" value="${cartItem.bookId}"/>
Let the submit button be just this way:
<input type="submit" value="Remove"/>
EDIT:
Yes, you have to create a form element for each book:
<c:forEach var="cartItem" items="${sessionScope.cart.cartItems}">
<tr>
<td><c:out value="${cartItem.title}" /></td>
<td>
<form method="post" action="removeBookFromCart">
<input type="submit" value="Remove"/>
<input type="hidden" name="remove" value="${cartItem.bookId}"/>
</form>
</td>
</tr>
</c:forEach>