How To Retrieve an Object's Value Defined Using c:set ... Tag?

Question

I have the value of a variable defined in JSP#1 (JSP#1 is not a form) using JSTL tag:
   <c:set var="id" value="${articleForm.article}" scope="session"/>Now, I have an object 'id' in the session scope. The object 'id' and all the information, which are defined in JSP#1, are forwarded to JSP#2.
JSP#2 is a form. But, the 'id' is not used in JSP#2.
JSP#2 has a submit button and then, a servlet takes over the control after that button is clicked. All the text fields in JSP#2 together with the object 'id' are forwarded to this servlet.
I have two questions:
1. I should put this object 'id' in a request scope or a session scope? Currently, it is in a session scope.
2. How to retrieve the value of this object 'id' in this servlet? (I do not want to print the value out. I want to retrieve the value and store it in a database.)
    int articleID = Integer.parseInt( session.getAttribute( "id" ) );   or, it should be retrieved in another way?

Answer 1

I'm not sure you understand the concept of a session object.
Java objects stay on the server. There is no transmission between the web browser and the client.
The scope just sets how long the server "remembers" that variable.
request scope - only lasts one request. Once a web page is returned to the client, the server forgets all request variables.
session scope - lasts for one user - across multiple requests/web pages.
1. I should put this object 'id' in a request scope or a session scope? Currently, it is in a session scope.From your description, you appear to have it right - your object should be in session scope.
2. How to retrieve the value of this object 'id' in this servlet? (I do not want to print the value out. I want to retrieve the value and store it in a database.)If articleForm.article is an String then that looks the right way to access it.
You might have to do it like this:
int articleID = Integer.parseInt( (String)session.getAttribute("id"));
The Integer.parseInt method takes a String as a parameter - while session.getAttribute() returns an Object.
This code will work if the object stored in the session is a String.
The object stored in the session is ${articleForm.article} What type does articletForm.getArticle() return? That is the type you need to cast it to when retrieving it from the session.
Cheers,
evnafets