View cannot be restored exception

[Gvn Karthik]

Hi,

I'm using Eclipse Helios, Apache Tomcat 6.0.29 and JSF 1.2. I'm having a simple application which has a Login page, Home Page and a Logout page. Once the user logs in, a session variable is set and Home page is displayed which has a logout button. When I launch Eclipse and run the Login page and use the correct credentials, I'm able to go to the home page but when I re-run the Login page, I get an error saying "view cannot be restored".

How do I resolve this exception? PFB the exception.

type Exception report

message 

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

exception 

javax.servlet.ServletException: viewId:/Login.jsp - View /Login.jsp could not be restored.
	javax.faces.webapp.FacesServlet.service(FacesServlet.java:249)


root cause 

javax.faces.application.ViewExpiredException: viewId:/Login.jsp - View /Login.jsp could not be restored.
	com.sun.faces.lifecycle.RestoreViewPhase.execute(RestoreViewPhase.java:187)
	com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251)
	com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:117)
	javax.faces.webapp.FacesServlet.service(FacesServlet.java:244)


note The full stack trace of the root cause is available in the Apache Tomcat/6.0.29 logs.

Also, when I re-run the application and when the Login page comes up, I press the refresh button in the Eclipse browser and after that I dont get any such exception. If I dont refresh the login page after a re-run of the application, I get the above exception. How do I get rid of this exception?

[naveen gupta]

i am not sure i understood correctly

so are you trying to say, first time you login it works fine but after you logout and login again it fails?

[Guy deLyonesse]

Not sure why you're using a session variable. If you're in JSF then your login page should call a method in your backing bean that runs the authentication, and if successful, returns a success message. Your faces-config.xml should then have a navigation rule that will direct the user to the home page when login is successful.

If you're not sure how that works then I'd recommend getting a good JSF book or find a JSF tutorial online. Navigation rules are a basic part of JSF and would save you a huge amount of effort.

[Gvn Karthik]

Once the user logs in, he will be directed to a home page where he has to fill in a form which updates a table in the database in the back end. In that table I'm inserting the username across the user who has successfully logged in. That's why I'm using a session variable. Also, I can have tasks that can be done in a user-specific manner. If the user updates his personal details, then I can use the value of the session variable to query my database and update according to the user who has logged in.


But the exception which is coming up here is creating a problem, I mean it is trying to fetch a view which no longer exists. PFB the code in my backing bean.

package Beans;

import javax.faces.context.FacesContext;
import javax.faces.context.ExternalContext;
import javax.servlet.http.HttpSession;

import Services.LoginService;

public class LoginBean 
{
	private String username;
	private String password;
	private String message;
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public String getMessage() {
		return message;
	}
	public void setMessage(String message) {
		this.message = message;
	}
	
	public String validateLogin()
	{
		int returnValue=new LoginService().authenticate(this.username, this.password);
		
		if(returnValue==-1)
		{
			this.message="Invalid Username";
			return "failure";
		}
		
		if(returnValue==-2)
		{
			this.message="Invalid Password";
			return "failure";
		}
		
		HttpSession session=(HttpSession)FacesContext.getCurrentInstance().getExternalContext().getSession(true);
		session.setAttribute("user", this.username);
		return "success";
	}
	
	public String logout()
	{
		HttpSession session=(HttpSession)FacesContext.getCurrentInstance().getExternalContext().getSession(true);
		System.out.println((String)session.getAttribute("user"));
		session.invalidate();
		return "logout";
	}
}

Any suggestions to resolve this exception? But, here is the catch. When I run it for the second time after I launch eclipse and then refresh the login page by pressing the reload button on the eclipse browser; I don't get this exception. So, as a workaround I thought I will use javascript to automatically reload the login page as it loads. I know this is not how I should be doing but I think this might help.

[Guy deLyonesse]

I understand how you're using the session variable, I just think you'd be better off making it a member of the LoginBean class.

Anyway, what is the scope of your LoginBean as configured in your faces-config.xml?

[Gvn Karthik]

I have put the LoginBean class in session scope.

[Guy deLyonesse]

Have you only run this thing within Eclipse, or have you tried running it from within Tomcat separately?

[Gvn Karthik]

I didn't get your question. I have configured Tomcat as my server in Eclipse to run my application. And I run the application in Eclipse only.

[Guy deLyonesse]

I'd suggest deploying it to Tomcat separately, maybe on a separate instance of Tomcat on your machine, then see if you get the same behavior.

The reason is by eliminating Eclipse from the equation we can eliminate the possibility that there's an issue with different versions of .jars, etc.