Access Session attribute on jstl

I am trying to access a session attribute from a jsp page which is set and dispatched by a servlet, but I am getting the error message "jsp:attribute must be the subelement of a standard or custom action". What could be wrong, am I accessing it incorrectly? The following is the code snippet.

Servlet:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    HttpSession session = request.getSession(); 
    session.setAttribute("Questions", getQuestion());
    System.out.println(session.getAttribute("Questions"));
    RequestDispatcher req = request.getRequestDispatcher("DisplayQuestions.jsp");
    req.forward(request, response);
}

private QuestionBookDAO getQuestion(){
    QuestionBookDAO q = new QuestionBookDAO();
    q.setQuestion("First Question");
    q.setQuestionPaperID(100210);
    q.setSubTopic("Java");
    q.setTopic("Threads");
    return q;
}

I am able to set the session attribute successfully. But when I try to access the same in my jsp file (below), I am getting a runtime error

    <jsp:useBean id="Questions" type="com.cet.evaluation.QuestionBook" scope="session">
    <jsp:getProperty property="Questions" name="questionPaperID"/>
    <jsp:getProperty property="Questions" name="question"/>
    </jsp:useBean>

The bean QuestionBook contains two private variables questionPaperID and question I run the application on Tomcat a开发者_如何转开发nd below is the error thrown.

type Exception report

message 

    description The server encountered an internal error () that prevented it from fulfilling this request.

    exception 

    org.apache.jasper.JasperException: /DisplayQuestions.jsp(15,11) jsp:attribute must be the subelement of a standard or custom action
        org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:40)
        org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:407)
        org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:88)
        org.apache.jasper.compiler.Parser.parseStandardAction(Parser.java:1160)
        org.apache.jasper.compiler.Parser.parseElements(Parser.java:1461)
        org.apache.jasper.compiler.Parser.parseBody(Parser.java:1670)
        org.apache.jasper.compiler.Parser.parseOptionalBody(Parser.java:1020)
            ....

You should definitely avoid using <jsp:...> tags. They're relics from the past and should always be avoided now.

Use the JSTL.

Now, wether you use the JSTL or any other tag library, accessing to a bean property needs your bean to have this property. A property is not a private instance variable. It's an information accessible via a public getter (and setter, if the property is writable). To access the questionPaperID property, you thus need to have a

public SomeType getQuestionPaperID() {
    //...
}

method in your bean.

Once you have that, you can display the value of this property using this code :

<c:out value="${Questions.questionPaperID}" />

or, to specifically target the session scoped attributes (in case of conflicts between scopes) :

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

Finally, I encourage you to name scope attributes as Java variables : starting with a lowercase letter.

You don't need the jsp:useBean to set the model if you already have a controller which prepared the model.

Just access it plain by EL:

<p>${Questions.questionPaperID}</p>
<p>${Questions.question}</p>

or by JSTL <c:out> tag if you'd like to HTML-escape the values or when you're still working on legacy Servlet 2.3 containers or older when EL wasn't supported in template text yet:

<p><c:out value="${Questions.questionPaperID}" /></p>
<p><c:out value="${Questions.question}" /></p>

See also:

• Our Servlets wiki page

Unrelated to the problem, the normal practice is by the way to start attribute name with a lowercase, like you do with normal variable names.

session.setAttribute("questions", questions);

and alter EL accordingly to use ${questions}.

Also note that you don't have any JSTL tag in your code. It's all plain JSP.