page scope

[Ravi Bansal]

HFSJ page 416 (Answer 3).


I have doubt that if the attribute is set in the request scope by the servlet class and then is it possible to access that attribute in the JSP page using standard action <jsp:getProperty> having scope not mentioned explicity, which means that default scope for the standard action is Page.?

[Devaka Cooray]

If an attribute is not found in the page scope, then it looks on the request scope, then session scope, and finally on the application scope.

[Siphiwe Madi]

Hi Ravi,

Although i couldn't find any details about setting request scoped attributes on page 416 on book (HFS&J, 2nd Edition). But as its been mentioned on the book that:

In a Servlet there are 3 scope objects:

1. request (HttpServletRequest)
2. session (HttSession)
3. context (ServletContext)

Note: There is NO 'page' scope object (unless the servlet is generated from the JSP) &


In a JSP there are a total of 4 implicit scope objects:

1. request (HttpServletRequest)
2. session (HttSession)
3. application (ServletContext), which is basically same as context from servlet
4. page (PageContext)

Note: The JSP adds an addition scope object 'page'.

Therefore, in terms of your question if you set a request attribute inside the servlet it will be stored in
the 'request' scope and can only be accessed from a 'request'.

If you try to access the same request attribute in your jsp using the <jsp:useBean/> you must explicitly specify
the scope as 'request'

<jsp:useBean id="person" type="scwcd2.practice.Person" class="scwcd2.practice.User" scope="request"/>

If you don't explicitly specify the scope, it will look in the default which is 'page' and will return 'nothing'.

Regards,
Siphiwe Madi
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[Ravi Bansal]

I checked the 2nd edition and i found its corrected over there......in the same question scope has been mentioned explicitly.....i was reading the older edition of HFSJ..........


thanks for explanation anyways......Siphiwe

[vani venkat]

If an attribute is not found in the page scope, then it looks on the request scope, then session scope, and finally on the application scope.

this happens in EL. does it work for standard action as well?

[Siphiwe Madi]

vani venkat wrote:

If an attribute is not found in the page scope, then it looks on the request scope, then session scope, and finally on the application scope.

this happens in EL. does it work for standard action as well?

It doesn't seem to work with standard action. It works for EL yes. But for standard action you have to explicitly specify the attribute scope.

Ravi:
I hope your question has been answered.

Regards,
Siphiwe Madi
[SCJP, __, __]
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