Problem with method

[Farakh khan]

I am writing the following code in each and every class but want to create a method that do the same thing to get me rid off of writting each time in every class. I tried a lot but failed

	out.print("<link rel=stylesheet href=/css/khan.css type=text/css media=screen>");

	WebPage wp=new WebPage();//website graphic interface

	HttpSession session=req.getSession();
	String userID=(String)session.getAttribute("userID");	


	if(userID==null || userID.equals("") || userID.equalsIgnoreCase("null")){
	out.println(wp.pagePrint1()+
	"<br><br><center><span class=gull><b>Please Login</b></font></center>"+
	wp.pagePrint2());
	}
	else
	{
	//code
	{

Can anybody please help me?

Thanks in anticipation

[Paul Clapham]

Why don't we start with something you tried and thought would work?

[Bear Bibeault]

Or look up the concept of servlet filters.

[David Newton]

And JSPs.

[Farakh khan]

Thanks for your favorable replies. Appreciated!

I tried a lot but invain. Kindly help me to correct this method

import javax.servlet.*;
import javax.servlet.http.*;

public class SessionCheck{

    public static String Check() throws Exception {
   
	String msg="";

	WebPage wp=new WebPage();//website graphic interface

	HttpSession session=HttpServletRequest.getSession();
	String userID=(String)session.getAttribute("userID");	


	if(userID==null || userID.equals("") || userID.equalsIgnoreCase("null")){
	msg=wp.pagePrint1()+
	"<br><br><center><span class=gull><b>Please Login</b></font></center>"+
	wp.pagePrint2();
	
	}else{
	msg="1";
	}

    return msg;
  }
}

//Error:
Non-static method .getSession(); can not be referenced from a static context

[Bear Bibeault]

Correct it by getting rid of it. Authentication checking of this type should be done in a filter that you write and declare once.

[Farakh khan]

Bear Bibeault wrote:Correct it by getting rid of it. Authentication checking of this type should be done in a filter that you write and declare once.

Thanks for your prompt reply

I am totally not aware of filters and use to with methods.

[Bear Bibeault]

Now would be the perfect time to learn all about servlet filters.

[Andrew Monkhouse]

Filters can work on the data coming into your web application, or on the data leaving your web application. As such they can be used for such things that are common to all your code such as security on the way in, and setting the correct header information on the way out (although there are often better ways to do the later).

I would recommend a good book on developing for the web, such as Head First Servlets and JSP. Failing that, you might want to look at the Sun Java Servlet Technology tutorial, or a specific article on The Essentials of Filters.

[Farakh khan]

Andrew Monkhouse wrote:Filters can work on the data coming into your web application, or on the data leaving your web application. As such they can be used for such things that are common to all your code such as security on the way in, and setting the correct header information on the way out (although there are often better ways to do the later).

I would recommend a good book on developing for the web, such as Head First Servlets and JSP. Failing that, you might want to look at the Sun Java Servlet Technology tutorial, or a specific article on The Essentials of Filters.

Thanks for recomending tutorials and books but can you please solve my real problem right now as the project is in my hand and I have to deliver it within a few days. I believe the methods are still workable in java servlet but certainly will start with recomended books/tutorials

Thanks again & best regards

[David Newton]

Farakh khan wrote:I tried a lot but invain. Kindly help me to correct this method

public static boolean haveSessionUser(HttpSession session) throws Exception {
    String userId = (String) session.getAttribute(Attributes.SESSION_USER);
    return StringUtils.isNotBlank(userId);
}

[Farakh khan]

David Newton wrote:

Farakh khan wrote:I tried a lot but invain. Kindly help me to correct this method

public static boolean haveSessionUser(HttpSession session) throws Exception {
    String userId = (String) session.getAttribute(Attributes.SESSION_USER);
    return StringUtils.isNotBlank(userId);
}

Wow! great! Appreciated!!

Thanks from the bottom of my heart and yes Thanks also to recommend some tutorials regarding filters. I started to studied them

Best Regards

[Farakh khan]

Farakh khan wrote:

David Newton wrote:

Farakh khan wrote:I tried a lot but invain. Kindly help me to correct this method

public static boolean haveSessionUser(HttpSession session) throws Exception {
    String userId = (String) session.getAttribute(Attributes.SESSION_USER);
    return StringUtils.isNotBlank(userId);
}

BUMP!!

Error:
Cannot find symbol:
-- Attributes
-- StringUtils

Shall I have to import some packages?

I tested by imorting java.util.* but not works

Please help me again. copy paste what am doing

import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class SessionCheck{

       public static boolean haveSessionUser(HttpSession session) throws Exception {  
        String userId = (String) session.getAttribute(Attributes.SESSION_USER);  
        return StringUtils.isNotBlank(userId);  
      
  }
}

Best Regards

[David Newton]

...

Obviously you'd need to adapt it to your own environment.

[Farakh khan]

David Newton wrote:...

Obviously you'd need to adapt it to your own environment.

I not understand completely. Can you please be more specific?

Thanks again & best regards

[David Newton]

Nobody here is going to write your code for you. I showed you one way to fix your method, including using a constant to define the attribute name, and using a third-party library to do the null/empty check. To be honest, I expected the code I wrote to be self-explanatory--I'm kind of at a loss to explain it any further without doing *all* your work for you, which is something we really try not to do here.

[Farakh khan]

David Newton wrote:Nobody here is going to write your code for you. I showed you one way to fix your method, including using a constant to define the attribute name, and using a third-party library to do the null/empty check. To be honest, I expected the code I wrote to be self-explanatory--I'm kind of at a loss to explain it any further without doing *all* your work for you, which is something we really try not to do here.

I am really thankful for you as you at least tried to help. Appreciated!

Its throwing compile time error not runtime or logical errors

ERROR-1:
cannot find symbol
symbol	: variable Attribute
location: class SessionCheck

ERROR-2:
cannot find symbol
symbol	: variable StringUtils
location: class SessionCheck

Anyhow working with it and if I succeeded will let you know

Thanks again

[David Newton]

I wrote the method the way *I* would have written it (well, with the caveat that this isn't how I'd do it). Obviously since I'm writing it the way *I* would write it I used the techniques and libraries *I* would use. You're not using them. So replace the stuff that you *don't* have with the stuff you *do*. It's really clear what the intent of the code I used is, or at least it *should* be.

[Farakh khan]

David Newton wrote:I wrote the method the way *I* would have written it (well, with the caveat that this isn't how I'd do it). Obviously since I'm writing it the way *I* would write it I used the techniques and libraries *I* would use. You're not using them. So replace the stuff that you *don't* have with the stuff you *do*. It's really clear what the intent of the code I used is, or at least it *should* be.

Thanks again for guidance. Will let you know about the progress soon

Appreciated