Very funny behavior of sessions...

[Timothy Sam]

Hi, I tried creating a session like the following...

My Servlet class

String errorFlag = "true";
session.setAttribute("errorflag", "errorFlag");

and called it in my servlet like this...

String errorFlag = null;
errorFlag = (String) session.getAttribute("errorflag");

strangely... I get this exception...

type Exception report

message

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

exception

org.apache.jasper.JasperException: Unable to compile class for JSP

An error occurred at line: 3 in the jsp file: /timeoutsys/login.jsp
Generated servlet error:
Incompatible operand types String and boolean


org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:328)
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:409)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:288)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:267)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:255)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:563)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:293)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


note The full stack trace of the root cause is available in the Apache Tomcat/5.5.12 logs.

[David O'Meara]

Is there just the one JSP, or do you include any others? If you change a 'nested' JSP, sometimes it desn't get picked up and recompiled. You can delete the contents of your <tomcat_home>/working directory to force it to build it again.

[Timothy Sam]

Hi, I process my JSP like this...


JSP Input - > Process data/create sessions in servlet -> JSP get session/Disply

there is only one JSP involved in this process... If the code need be posted, I'd gladly do it. I just think it's too lengthy with the JSP. Thanks!

[Timothy Sam]

Hi, please consider this code...

My Servlet

package timeoutsys;
 
import java.io.*;
 
import javax.servlet.*;
import javax.servlet.http.*;
 
public class ProcessLoginForm extends HttpServlet
{
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException
    {
        String action = request.getParameter("action") == null ? "" : request.getParameter("action");
        [B]String errorFlag = null;[/B]
 
        InputBean ib = new InputBean();
 
        if (action.equals("log"))
        {
            ib.setUsername(request.getParameter("username"));
            ib.setPassword(request.getParameter("password"));
 
            try
            {
                if (ib.validateLog() == true) //username and password is found
                {
                    System.out.println("Validated");
                    [B]errorFlag = "false";[/B]
                    //redirect to servlet ---> jsp to display user have logged out/in
                }
                else
                {
        HttpSession session = request.getSession();
        [B]errorFlag = "true";
        session.setAttribute("ib", ib);
        [b]session.setAttribute("errorflag", errorFlag);[/B]
        response.sendRedirect("login.jsp");
    }
    }
catch(Exception err)
{
System.out.println("Error: " + err.toString());
}
 
        }
 
        //out.println("<br>Action: " + action);
        //out.println("<br>Username: " + ib.getUsername() + "<br>Pass: " + ib.getPassword());
 
    }
 
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException
{
doPost(request, response);
}
}

My JSP page...

<%@ page import="timeoutsys.InputBean" %>
 
<%
    InputBean ib = new InputBean();
    [B]String errorFlag = null;[/B]
    
    if (session.getAttribute("errorflag") != null)
    {
        [B]errorFlag = (String) session.getAttribute("errorflag");[/B]
    }
    else
    {
        [B]errorFlag = "false";[/B]
    }
    
    [B]System.out.println("errorFlag: " + errorFlag);[/B]
    
    
    if ( [B]errorFlag == true[/B])
    {
        if ( session.getAttribute("ib") !=  null)
        {
        ib = (InputBean)session.getAttribute("ib");
        //errorFlag = 
        }
    }
 
    //ib = (InputBean)session.getAttribute("inputbeanobject") == null ? new InputBean() : (InputBean)session.getAttribute("inputbeanobject");
    System.out.println("Value of ib: " + ib);
%>
<html>
 
<head>
<meta http-equiv="Content-Language" content="en-us">
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<title>Username</title>
</head>
 
<script>
    function processForm()
    {
        loginform.submit();
    }
</script>
 
<body>
 

<br>
<br>
<br>
<br>
<br>
 
<!-- /timeoutsys/ProcessForm -->
 
<form method="POST" action="/timeoutsys/ProcessLoginForm" name="loginform">
 
<input type="hidden" name="action" value="log">
 
<div align="center">
<table border="0" width="403" height="130" id="table2">
<tr>
<td height="34" width="62"><b><font face="Arial">Username:</font></b></td>
<td height="34" width="323">
<input type="text" name="username" size="20" tabindex="1" ON></td>
</tr>
<tr>
<td height="29" width="62"><b><font face="Arial">Password:</font></b></td>
<td height="29" width="323">
<input type="password" name="password" size="20" tabindex="2"></td>
</tr>
<tr>
<td height="57" width="62" rowspan="3"> </td>
<td height="24" width="323">
<table border="0" width="152" id="table3" bordercolor="#000000">
<tr>
<td width="67">
<input type="button" value="Log-In/Out" name="action" onUserClick="javascript :-P	 rocessForm()"></td>
<td width="69">
<input type="reset" value="Reset" name="action"></td>
</tr>
</table>
</td>
</tr>
<tr>
<td height="10" width="323"><font size="1" color="#FF0000"><% out.println(ib.getErrorMsg("usernamepassword")); %></font></td>
</tr>
<tr>
<td height="7" width="323"><font face="Arial" size="1">
<a href="addemployee.jsp">Go to registration page</a></font></td>
</tr>
</table>
</div>
 
</form>
 
</body>
 
</html>

I really help someone could help me... I always have problems when casting a session to a primitive type like int or bool... Thanks!

[Antonio Giovanni]

if ( errorFlag == true)

Here there definitely is a problem,..
Incompatible operands ( String and boolean) ??

[Antonio Giovanni]

I am sorry, before i wrote the complete thing i accidently clicked the
Add Reply..

Anyway coming back to the problem, instead of
if ( errorFlag == true) it should be

if(errorFlag.equalsIgnoreCase("true"))

[Kyle Brown]

Given that the compiler error is on login.jsp I think it would be useful if you showed us login.jsp.

Kyle

[Timothy Sam]

Thanks for your help! I guess I got a little dizzy while looking at my source code(didn't even notice my own mistake). But thanks alot!