request Vs Response object in web application

In web application request is sent by client(browser) then response is constructed by server and send to client. But once request reach server side , some data put in request object. Why those data kept in request.
For ex: user send two integer a and b ,ask the server to add the two values and return its result. once the request reach the server ,both integer values should taken from request and result should be placed in response object or request object ???.

As per my understanding, request should not exist once it enter server and its data extracted .

Please suggest in this

The client won't get the request back. In the server side you can use the request object to access the initially entered request parameters and/or the request attributes (such as javabeans) in the JSP file.

1)so when the data is placed in response object.after data placed in response ,when it send to browser
2)if response object created then request object is destroyed???

Or, are you confused by the fact that you've seen data put into a request before being forwarded off to a JSP?

Here I add some code example,I add struts sample,

public class SearchTutorialAction extends Action
{
  public ActionForward execute(
    ActionMapping mapping,
    AtionForm form,
    HttpServletRequest request,
    HttpServletResponse response) throws Exception{
	SearchTutorialActionForm formObj = (SearchTutorialActionForm)form;

System.out.println("Getting session factory");
	 /*Get the servlet context */
	 ServletContext context = request.getSession().getServletContext();
	 /*Retrieve Session Factory */
	 SessionFactory _factory = (SessionFactory)  context.getAttribute(HibernatePlugIn.SESSION_FACTORY_KEY);
	 /*Open Hibernate Session */
	 Session  session = _factory.openSession();
     //Criteria Query Example
     Criteria crit = session.createCriteria(Tutorial.class);
     crit.add(Restrictions.like("shortdesc", "%" + formObj.getKeyword() +"%")); //Like condition

//Fetch the result from database
	[b] List tutorials= crit.list();
	 request.setAttribute("searchresult",tutorials);[/b]
	 
	  /*Close session */
      session.close();
	  System.out.println("Hibernate Session Closed");
      return mapping.findForward("success");
  }
}

List of object created here and put into request. Why,instead i can code like this

please clear my confusion

The purpose is so that the JSP will have access to the data after the forward.

jacob deiter wrote:In web application request is sent by client(browser) then response is constructed by server and send to client. But once request reach server side , some data put in request object. Why those data kept in request.
For ex: user send two integer a and b ,ask the server to add the two values and return its result. once the request reach the server ,both integer values should taken from request and result should be placed in response object or request object ???.

As per my understanding, request should not exist once it enter server and its data extracted .

Please suggest in this

The client sends the request to the server.The container choose the corresponding servlet specified in the url.Then servlet calls its business logic i.e the model.After getting the result from the model the servlet adds it to the request object by setAttribute method. After that the view(JSP etc) gets the result from the request object by getAttribute method and then forwards it to container as a response.

Please correct me if i am wrong as i am also a starter

That's all pretty close except for this part:

Ankitt Gupta wrote: and then forwards it to container as a response.

The term "forward" has a specific meaning within a web application and the response is not forwarded, and it is not sent to the container. Rather, the container returns the response to the client.

jacob deiter wrote:Here I add some code example,I add struts sample,

public class SearchTutorialAction extends Action { public ActionForward execute( ActionMapping mapping, AtionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception{ SearchTutorialActionForm formObj = (SearchTutorialActionForm)form; System.out.println("Getting session factory"); /*Get the servlet context */ ServletContext context = request.getSession().getServletContext(); /*Retrieve Session Factory */ SessionFactory _factory = (SessionFactory) context.getAttribute(HibernatePlugIn.SESSION_FACTORY_KEY); /*Open Hibernate Session */ Session session = _factory.openSession(); //Criteria Query Example Criteria crit = session.createCriteria(Tutorial.class); crit.add(Restrictions.like("shortdesc", "%" + formObj.getKeyword() +"%")); //Like condition //Fetch the result from database [b] List tutorials= crit.list(); request.setAttribute("searchresult",tutorials);[/b] /*Close session */ session.close(); System.out.println("Hibernate Session Closed"); return mapping.findForward("success"); } }

List tutorials= crit.list(); request.setAttribute("searchresult",tutorials);

List of object created here and put into request. Why,instead i can code like this

List tutorials= crit.list(); response.setAttribute("searchresult",tutorials);

please clear my confusion

Hi Jacob,

You can never set an attribute on a response object.
Now if you want to pass some information from the servlet to say a Jsp,you have two ways of doing that-->

1) Use a RequestDispatcher
In this case the transfer of the control happens at the server side.So the request is the same and thus you can set
the attribute in the request scope and get the attribute in the Jsp.

2) Use redirection
In this case the browser does the work that is generates a new request to the Jsp.
Hence setting and getting in the request scope wont work.
Then to transfer information you can say set and get attributes using session or ServletContext scope.