Solved

Servlet argument passing

Posted on 2003-11-12
10
612 Views
Last Modified: 2013-11-24
Hi all. How can I pass arguments between servlets? I read arguments from HTML forms, but I can't find any resources on passing between servlets. E.g. via the url string with the '?' part...

0
Comment
Question by:piou
  • 4
  • 4
  • 2
10 Comments
 
LVL 1

Accepted Solution

by:
arunec earned 75 total points
ID: 9730081
Hi,
You can use :

In your servlet1 :

session.setAttribute("Test1", Test1 );
session.setAttribute("Test2", Test2 );

In your servlet2 :

String l1 = (String)session.getAttribute("Test1");
String l2= (String)session.getAttribute("Test2");

or u can use RequestDispatcher

request.setAttribute("test1", test1);    
   
RequestDispatcher dispatcher =
getServletContext().getRequestDispatcher();
dispatcher.forward(request, response);

Regards,
arunec
0
 

Author Comment

by:piou
ID: 9730364
Thanks arunec. I was looking for something more simple, related to the getQueryString() method. Is there any automation implemented? Or should I just build *manually* the URLs so that the contain a tail after the '?', and then process that with a StringTokenizer...?

0
 

Author Comment

by:piou
ID: 9730479
Ok, I think I'm closer. There are these methods:

getQueryString()
getParameterNames()
getParameterValues()

But the API docs are not very clear on their usage. I think the answer lies around these methods, but I cannot find proper resources.

0
 
LVL 7

Expert Comment

by:grim_toaster
ID: 9730531
If you can avoid it, it is best to leave sessions out of the picture (unless there is one there already).

I would suggest looking into the ServletRequest interface methods setAttribute, getAttribute and getParameter, depending on your needs.  It would also be best to avoid writing your own code to deal with the query string, as there is already code availabel.

After you've set the value required to the request object, you can dispatch to the other servlet as stated by arunec.
0
 

Author Comment

by:piou
ID: 9730708
It doesn't seem to work. Shouldn't I set the ServletResponse instead? But only the request has a setAttribute() method. Doesn't make sense...
0
3 Use Cases for Connected Systems

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, testing some more, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us.

 
LVL 7

Expert Comment

by:grim_toaster
ID: 9731071
You should be setting the attribute to the ServletRequest.  Ah, one slight problem with Arumec's code, when acquiring the request dispatcher you will need to specify the path of the resource you are trying to access:

request.setAttribute("name", "value");
RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/relative/path/servlet");
dispatcher.forward(request, response);

Then in the servlet you dispatch the call to, do:
String value = request.getAttribute("name");
0
 
LVL 1

Expert Comment

by:arunec
ID: 9737128
yaa, i missed the path in RequestDispatcher,thanx grim
0
 
LVL 7

Expert Comment

by:grim_toaster
ID: 9737781
No problem!  Oops, I also missed something in my code!  The request.getAttribute("name"); call returns an Object, this will need to be cast to a String.
0
 

Author Comment

by:piou
ID: 9737895
Thank you guys. I hope grim has no problem for arunec to take the points, being first...
0
 
LVL 7

Expert Comment

by:grim_toaster
ID: 9746392
Nope, none whatsoever!  Sorry it's taken a while to reply!  I lost the link!
0

Featured Post

DevOps Toolchain Recommendations

Read this Gartner Research Note and discover how your IT organization can automate and optimize DevOps processes using a toolchain architecture.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
json example 39 131
Printing to a specific printer tray (HP 806dn printer) 3 83
Core Java. What output will be and why ? 6 65
Strange loading of website behaviour 3 31
For beginner Java programmers or at least those new to the Eclipse IDE, the following tutorial will show some (four) ways in which you can import your Java projects to your Eclipse workbench. Introduction While learning Java can be done with…
Are you developing a Java application and want to create Excel Spreadsheets? You have come to the right place, this article will describe how you can create Excel Spreadsheets from a Java Application. For the purposes of this article, I will be u…
Viewers learn about the “while” loop and how to utilize it correctly in Java. Additionally, viewers begin exploring how to include conditional statements within a while loop and avoid an endless loop. Define While Loop: Basic Example: Explanatio…
This tutorial covers a step-by-step guide to install VisualVM launcher in eclipse.

919 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

17 Experts available now in Live!

Get 1:1 Help Now