Problem with arrayList e session jsp

Question

I have a problem with my program.

I have a servlet; in this servlet save the session attribute

ArrayList<Integer> list = new ArrayList<Integer>;
list.add(1);
request.getsession().setAttribute("list",list);

Now the attribute is a String and not an ArrayList. In fact when i try to do:

request.getsession().getAttribute(list)

is a string and not an Array.

I want an Array.

Thanks

Vincent Ramdhanie · Accepted Answer · 2011-01-07 17:40:35Z

5

You have to cast when you get the attribute from the session like this:

 ArrayList<Integer> list = (ArrayList<Integer>)request.getsession().getAttribute("list");

And the attributes in the session are stored in a map, that is why the key you used is a String and you have to use a string to retrieve the value.

edited Jan 7, 2011 at 17:40

answered Jan 7, 2011 at 17:34

Vincent Ramdhanie

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6 Comments

Vincent Ramdhanie Over a year ago

@zp26 What is the problem with it?

zp26 Over a year ago

Multiple markers at this line - Type safety: Unchecked cast from Object to ArrayList<Integer>

Vincent Ramdhanie Over a year ago

@zp26 Fixed. Also org.life.java - Jigar Joshi had it correct all along.

Renan Over a year ago

@zp26 this is not a problem.. Just change the cast to ArrayList<Integer> list = (ArrayList<Integer>)object and the "Unchecked" will disappear. "The local variable.." that means you are not using the variable along the rest of the code (or sometimes it bugs when you use it inside some conditions, cant remember very well wich ones).

zp26 Over a year ago

Sorry but the Unchecked cast don't disappear.

|

Jigar Joshi · Accepted Answer · 2011-01-07 17:34:27Z

1

session.getAttribute(..) returns Object

You will have to cast it like

List<Integer> list = (List<Integer>)request.getsession().getAttribute("list");

answered Jan 7, 2011 at 17:34

Jigar Joshi

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Comments

Community · Accepted Answer · 2017-05-23 12:26:56Z

1

As answered in your previous questions, just access it by EL in JSP.

${list}

If you want to iterate over it, use JSTL c:forEach:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
...
<c:forEach items="${list}" var="item">
    ${item}<br />
</c:forEach>

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