Spring MVC Tutorials 12 - Understanding @ModelAttribute annotation 02 ( using at a method level ) Video Lecture | MVC Tutorials: Web Programming Course - Web Development

welcome back guys this tutorial is in
continuation with the earlier one where
we learned how to use model attribute
annotation on a method argument like
this on this tutorial I'm gonna talk
about how to use the same annotation at
a method level along with looking at
some more fundamental concepts which are
related to this annotation all right
let's start because before I start
explaining how to use this annotation at
a method level let me make a very small
change in this request handler method
and the corresponding JSP file and later
I'll explain everything to you in detail
all right so I've done here I've added
this statement here in this GSB file on
top of the page and here I've added this
statement and this request handler
method now let's understand what I've
done here here I've added a string
object head of message in this success
handler methods model and view object
having this value and in the
corresponding just B file that is in
admission form dot JSP file
I'm simply accessing this string objects
value with this code now with this
modification if a user would access this
web page what will happen nothing much
user would see this string objects value
printed on the top of this web page
along with this code that is a value
gone to college of engineering India
which is set here by this equation
method using this statement let me show
you this working on the browser earlier
when I was typing this URL on the
browser my application was sending me
this web page now if I type the same URL
on the browser and would hit enter after
the modifications which we just made my
applique
has sent me this webpage as a response
with this additional text on top of this
webpage and this is because of the
modifications which I made in this
request under method and in the
corresponding jest default that is this
modification now after this modification
I would want you to observe a very
important point here in this controller
class here in this controller class I
have to request handler methods and boot
request handler methods are putting same
kind of object in the respective model
and view object that is had a messaging
object our spring MVC says if you have a
requirement like this they're all
requests to handler methods which are
present in the same controller class or
putting or adding same kind of object in
the respective model and view object
then this is the right way of doing
things and there is no doubt about it
but how about if I give you an option
here for adding less code and do more
things using model attribute annotation
on a method let me clean you this way
spring MVC says if you had a method like
this in your controller class which is
having model attribute annotation
present on its top then whatever object
you would add to its model object spring
MSE would automatically add that object
to the model and view object for each
request handler method which is present
in this controller class in simple words
if I talk about after adding this method
here in this controller class and
putting Headroom Assisting object with
this value into this model object I am
simply saying that I really don't need
to write this statement
individually in all request handler
methods which are present in this
controller class so I can simply remove
the mouse from this controller class
from each request handler method guys
just now I showed you using moderate
good annotation on a method and putting
had am assisting object having this
value into the model object for this
method I simply avoided adding had an
existing object individually in each
request handle method so here I cannot
achieve more things with less code using
this way so when you use model attribute
annotation on a method it's not giving
you some outstanding feature but it's
simply giving your way so that you would
write less code and do more things so if
you don't want to use model attribute
annotation on a method don't use that
but in that case you will need to write
more code as we saw before I included
this method here in this controller
class I believe with all these
modifications which I just performed in
this controller class my applications
behavior would not change and it would
behave in the same manner as it was
behaving before making all this
modifications let's check it on the
browser cool my application has sent me
a response in the same way as it was
sending me before I made all those
modifications in this control class
because here in this demo I showed you
an example where I added a string object
to this model object in the similar
manner you may add here any user-defined
object of your choice or any collection
object of your choice to this model
object as per your projects requirement
also I added here only one object to
this model in your project you may add
more objects to this model object by
simply adding more statements like this
in this method now you know something
like this you keep on adding more
statements like this and in each
statement you provide here the object
which you want to place here in this
model object alright
because there is an important point you
should not hear when every controller
class is having a method like this that
is method having model attribute
annotation present on its top then
spring MVC framework would always make a
call to that method first before making
call to any of its request handler
methods I hope you got the point there
is a big thank you for like any
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