Problem with session attributes in JSP EL using Spring MVC

问题

I'm trying to show a session attribute "userSession" in a jsp page using JSP EL, but it returns null (case 1). Request attributes are shown properly in EL expressions though.

Using java scriptlet instead, behaves as shown in cases 2 and 3:

1. <c:out value="${userSession}"/> \\Returns null
2. <c:out value='<%=request.getSession().getAttribute("userSession")%>'/> \\Works fine - returns session attribute
3. <c:out value='<%=session.getAttribute("userSession")%>'/> \\Throws exception: cannot find variable session

Exception of case 3 may be related to case 1 problem, something like not recognizing the session variable for some reason and that affecting the EL expression then.

I'm using Spring MVC 2.5 and JSTL 1.1.2.

I can post anything else needed to clarify the problem.

回答1:

Fixed. Problem was with a <%@ page session="false" %> directive found in an include.jsp used by my page, which I removed from that global place.

It prevents a jsp page from access to session scope variables. So only <%=request.getSession().getAttribute("foo")%> works in that case...

回答2:

What does:

<c:out value="${sessionScope.userSession}"/>

or

<c:out value="${sessionScope['userSession']}"/>

give?

回答3:

<c:out value="${sessionScope}"/> or just ${sessionScope} list all the attributes in portlet application scope.

so, You can try to get your attribut with this expression !

来源：https://stackoverflow.com/questions/4730790/problem-with-session-attributes-in-jsp-el-using-spring-mvc