accessing servlets using submit buttons

[ros]

Hi,

I am not very experienced in servlets and am working on making a
simple shopping cart. This application has 3 servlets and one of these
servlets (ReviewShoppingCart) has a form which has 2 submit buttons.
One button should point to AddToShoppingCart servlet and the other
should point to RemoveFromCart.

But I don't really know how to have the if/else code for that. I mean
I tried the code and it is pasted below.

String actionString = request.getParameter("Submit");

if (actionString.equals("Add More Items")) {
System.out.println("addToShoppingCart");
AddToShoppingCart(request, aPW);
}else if (actionString.equals("Remove From Basket")) {
RemoveItemsFromCart(request, aPW);
System.out.println("reviewShoppingCart");
}



Please help me with this. I would be extremely grateful.
ros

 

[Richard Senior]

I am not very experienced in servlets and am working on making a
simple shopping cart. This application has 3 servlets and one of these
servlets (ReviewShoppingCart) has a form which has 2 submit buttons.
One button should point to AddToShoppingCart servlet and the other
should point to RemoveFromCart.

An HTML form can only submit to one place:

<form action="myServlet" method="post">

....

<input type="submit" value="Add to Cart">
<input type="submit" value="Remove from Cart">

</form>

You could have two forms in the HTML rendered by the ReviewShoppingCart,
with one button in each and different action paths.

<form action="AddToCart" method="post">

....

<input type="submit" value="Add to Cart">

</form>

<form action="RemoveFromCart" method="post">

....

<input type="submit" value="Remove from Cart">

</form>

But I would combine your AddToShoppingCart and RemoveFromCart servlets
into a single servlet and choose your action based on the button that
was pressed:

<form action="EditShoppingCart" method="post">

....

<input name="action" type="submit" value="Add to Cart">
<input name="action" type="submit" value="Remove from Cart">

</form>

This will add an additional parameter to the request called "action"
that will be set to "Add to Cart" or "Remove from Cart".

Then in your servlet:

String action = request.getParameter("action");

if ("Add to Cart".equals(action)) {
...
}
else if ("Add to Cart".equals(action)) {
...
}
else {
...
}

 

[Lew]

An HTML form can only submit to one place:

<form action="myServlet" method="post">

...

<input type="submit" value="Add to Cart">
<input type="submit" value="Remove from Cart">

</form>

You could have two forms in the HTML rendered by the ReviewShoppingCart,
with one button in each and different action paths.

<form action="AddToCart" method="post">

...

<input type="submit" value="Add to Cart">

</form>

<form action="RemoveFromCart" method="post">

...

<input type="submit" value="Remove from Cart">

</form>

But I would combine your AddToShoppingCart and RemoveFromCart servlets
into a single servlet and choose your action based on the button that
was pressed:

<form action="EditShoppingCart" method="post">

...

<input name="action" type="submit" value="Add to Cart">
<input name="action" type="submit" value="Remove from Cart">

</form>

This will add an additional parameter to the request called "action"
that will be set to "Add to Cart" or "Remove from Cart".

Then in your servlet:

String action = request.getParameter("action");

if ("Add to Cart".equals(action)) {
...
}
else if ("Remove from Cart".equals(action)) {
...
}
else {
...
}

Take a look at the Model-View-Controller (MVC) pattern, a.k.a. "Front
Controller" or "Dispatch".