servlet & jsp related doubt

[vianyrajnish rajnish]

hi all ,

This is taken from Kathy Sierra..Head first jsp and servlets

jsp code is like this below:

<jsp:useBean id="person" type="foo.Employee">
<jsp:setproperty name="person" property="name" value="Fred" />
</jsp:useBean>

Name is <jsp:getProperty name="person" property="name" />


questions are :
what happens if the sevlet code is like this

1) foo.Person p = new foo.Employee();
p.setName("Evan");
request.setAttribute("person",p);

answer :
fails at request time . The person attribute is stored at request scope
so <jsp:useBean > tag wont work because it can't find bean attribute .

2) foo.Employee p = new foo.Employee();
p.setName("Evan");
request.setAttribute("person",p);

answer : this works fine and prints out "Evan"

-------------------------------------------------

my doubt is in both 1) and 2) question the person attribute is having request scope only ...then how the 2) will run succesfully.
( in jsp above ther is no scope , so default is page scope )


can anyboby please answer this ..

thanks,

Viany Rajnish
[ July 11, 2007: Message edited by: Bear Bibeault ]

[Ben Souther]

Are you missing something?
1) and 2) look the same to me.

Did you mean to post a second version of the JSP code?

[Ben Souther]

Please do not post the same question in multiple forums.
This is called cross-posting.
It causes confusion and duplication of effort which will annoy the people who would otherwise help you making it less likely that you will get an answer to your question.

I closed the topic in the JSP forum.

If you're not getting an answer to your question, maybe you could improve the question. We have some tips for doing so here

[vianyrajnish rajnish]

hi,

questions 1) and 2) are not same

1) foo.Person p = new foo.Employee();
p.setName("Evan");
request.setAttribute("person",p);



2) foo.Employee p = new foo.Employee();
p.setName("Evan");
request.setAttribute("person",p);

--------------------------

here Employee class is inheriting Person class.

See the assignments objects of references

Thanks,
Vinay Rajnish

[Bear Bibeault]

The only difference is how p can be used in the servlet after its declarations. In one, p can only be treated as a Person. In two, it can be treated as an Employee.

What happens later, like in a JSP, depends on what you do later.
[ July 13, 2007: Message edited by: Bear Bibeault ]

[Joe Harry]

Did you try to check the errata for this? Check it at http://www.oreilly.com/catalog/headservletsjsp/errata/headservletsjsp.confirmed

[vianyrajnish rajnish]

Hi Jothi Shankar Kumar,


Thanks for the reply ... I found the error following the errata ..

but who writes these errata for the book...

( this is not to be posted here but i am curious to know)

thanks all

Vinay rajnish

[Joe Harry]

I guess if you visit the SCWCD forum, there is a link which leads you to the errata website. Also note that, any software book will for sure have a site dedicated to errata's. You can be doubly sure of that.

[vianyrajnish rajnish]

hi Jothi Shankar Kumar,

Thank you....


thanks ,

Vinay rajnish