How to set session attributes in a bean?

Question

How do I set a session attribute in a server-side bean?
I'm not sure if I asked the question the right way. What I meant is, while it's easy to set session attributes in a JSP page (session.setAttribute("sessionname", "sessionvalue")), I'd want to set such an attribute within a server-side bean defined in this web application. But what is the syntax for doing it?

Answer 1

Here a simple bean that stores something in the session and retrieves something from it.
import javax.servlet.http.HttpSession;
public class TestBean {
  private String value;
  public void doSomething(HttpSession session, int a, int b) {
    if (a+b > 0) {
      session.setAttribute("ab",Boolean.TRUE);
    } else {
      session.setAttribute("ab",Boolean.FALSE);
  public void init(HttpSession session) {
    if (session != null) {
      Boolean b = (Boolean)session.getAttribute("ab");
      if (b == Boolean.TRUE) {
        value = "a + b is greater than zero";
      } else {
        value = "a + b is not greater than zero";
    } else {
      value = "no session";
  public String getValue() {
    return value;
}In your JSP, use something along the lines of :
<%
  TestBean bean = new TestBean();
  bean.init(session);
  bean.doSomething(session,1,2);
%>If your bean only lives during one request, you can pass the session to the constructor, which stores it in a private variable. This saves passing the session each time.
Hope this helps,
--Arnout