SessionServlet.java

package examples.servlets;


import examples.utils.common.ExampleUtils;
import java.io.IOException;
import java.io.PrintWriter;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.servlet.ServletException;
import javax.servlet.http.*;
import weblogic.management.MBeanHome;


public class SessionServlet extends HttpServlet 
{ 
  
  public void doGet  HttpServletRequest(req, HttpServletResponse res)
       throws ServletException, IOException
  {
    //Get the session object
    HttpSession session = req.getSession(true);



    // Local variables

    String serverName;
    String failoverMessage = "";
    String str = (String) session.getAttribute("simplesession.servername");
    PrintWriter out = res.getWriter();
    Integer ival;


    // set content type and other response header fields first

    res.setContentType("text/html");
    

    // Retrieve the count value from the session

    ival = (Integer) session.getAttribute("sessiontest.counter");
    if (ival==null) ival = new Integer(1);
    else ival = new Integer(ival.intValue() + 1);
    
    session.setAttribute("sessiontest.counter", ival);

    out.println(ExampleUtils.returnHtmlHeader("Session Servlet"));

    try 
    {
      serverName = getServerName();
      if (str != null && str.equals(serverName)) failoverMessage = "";
      else failoverMessage = " (failing over from server" +str+ ")";
      session.setAttribute("simplesession.servername", serverName);


      // then write the data of the response

      out.println("You have hit this page <b> + ival + "</b> times.<p>);
      out.println("The server currently hosting this session is <B> + serverName + "</B> + failoverMessage + "<p>);

      // when the user clicks on the link in the next line,
      // the SessionServlet is called again,
      // but now URL rewriting is turned on

      out.println("Click <a href=" + res.encodeURL("SessionServlet") + ">here</a>);
      out.println(" to ensure that session tracking is working even " + "if cookies aren't supported.<br>);
      out.println("Note that by default URL rewriting is not enabled " + "because of its expensive overhead");
      out.println("<p>);
      out.println("<h4>Request and Session Data:</h4>);
      out.println("Session ID in Request: " + req.getRequestedSessionId());
      out.println("<br>Session ID in Request from Cookie: " + req.isRequestedSessionIdFromCookie());
      out.println("<br>Session ID in Request from URL: " + req.isRequestedSessionIdFromURL());
      out.println("<br>Valid Session ID: " + req.isRequestedSessionIdValid());
      out.println("<h4>Session Data:</h4>);
      out.println("New Session: " + session.isNew());
      out.println("<br>Session ID: " + session.getId());
      out.println("<br>Creation Time: " + session.getCreationTime());
      out.println("<br>Last Accessed Time: " + session.getLastAccessedTime());
    } 
    catch (Exception ex) 
    {
      out.println("<p><b>!! Example Failed !!<br><br> The following exception occur:</b><br><br>);
      ex.printStackTrace(new PrintWriter(out));
      ex.printStackTrace();
    }
    finally 
    {
      out.println(ExampleUtils.returnHtmlFooter());
    }
  }

  private String getServerName() throws Exception 
  {
    String toReturn = null;
    Context myCtx = new InitialContext();
    MBeanHome mbeanHome = (MBeanHome)myCtx.lookup("weblogic.management.home.localhome");
    toReturn = mbeanHome.getMBeanServer().getServerName();
    if (toReturn == null) return "";
    else return toReturn;
  }
}