Spring MVC Tutorials 35 - Web Services 05 ( Using @PathVariable annotation with a REST API ...) Video Lecture | MVC Tutorials: Web Programming Course - Web Development

guys my name is Ankush Karev and I
welcome you to come to series so far in
the West series of tutorials
what overall Arshad I've showed how to
create a basic West API this one which
allows a client to request for all
student records which are present in
this application and to develop this
REST API what all steps we followed
we simply included this West API
controller method in the student
admission control about Java class and
we were done so now when I'm going to
make a get request using this REST API
this controller method is going to
return all students with cards as a
response so in general I can say that
this REST API controller method does the
job of retrieving all student records so
I can happily put this comment on top of
this method so when I'm going to make a
get request I would get all student
records as a response and whatever I've
just described in a very brief manner I
explained in detail till the last
tutorial now let's proceed further and
try to learn in this tutorial how to
develop a little more complex REST API
then this one alright let's start guys
what if a client has got a very unique
and a special requirement so what it
wants is when a get request has to be
made using this REST API then the
application should return all student
records but as soon as it specifies the
name of the specific student at the end
of this REST API like this in that case
this application should return the
information about only that specific
student whose name client has specified
within the West API itself so question
is what all steps we need to follow in
this spring and with your application so
as to develop such a complex REST API
you know which allows client to specify
a value within the REST API itself but
before I talk about what all steps we
need to follow to develop this first API
I ask you a question to develop this
REST API what all steps we followed we
only included this versed API controller
method in the student Edition controller
dot Java class right in the similar
manner guys if you want to support one
more API you know an API via a client
can specify the name within the REST API
itself we are required to just include a
new REST API controller method in the
student admission controller dot java
class and we would be done with that so
let me do one thing let me include the
REST API controller method which is
going to support search or St API and
later on I will explain every single
step every single related concept to you
in detail so let's start so here I am
done with including this REST API
controller method which supports this
REST API now let's understand every bit
of it step by step
case this controller method get' student
what job it performs let's try to
understand first it makes use of the
value of student name variable to fetch
these students information from the
database so it's going to create using
this student name to fetch the competing
formation about this student and then
it's going to make use of that
information to create
is student object and then return the
same as a response now what's the use of
request mapping annotation with this
pattern let's try to understand that
here client is going to specify John
sometimes Undertaker sometimes
colleagues sometimes this name sometimes
that means so this is not a hard-coded
string here client is supposed to be
specifying the value and there is no way
he is going to specify some hard-coded
string so here the challenges what I am
going to specify after students so that
whenever a client is going to specify a
value spring MVC framework is going to
map the same to this request mapping
annotation you know method this
controller method but the way to do that
is using curly braces so here if you
want trying to specify the hard-coded
string name then don't specify curly
braces but if you want trying to specify
the value of money in that case specify
curly braces so enclose name variable
under curly braces so what does it mean
it simply means whenever a client is
going to make use of a REST API they're
after students some value is their
spring MVC framework is simply going to
check that whole REST API which client
has used to make the request and if it's
going to find some value of the students
pattern it's going to assume that that
value is nothing but the value of name
and in that case it's going to simply
make a call to this REST API controller
method because of this request mapping
annotation and now question is how this
value you know value of name is going to
be assigned to student name well that is
happening because of this thought
variable annotation so the way path
variable annotation works
is whatever you specify after parks
variable annotation you know spring MVC
framework simply extract the value of
that variable from the rest api which
have which a client has used weekly in
request so after extracting that value
from that quest api is going to assign
the same to the variables which you have
to get after art variable annotation so
how this whole concept works when a
client is going to make a request using
this REST API spring MVC framework is
going to map this quest API request to
this particular controller method
because of this it was mapping
annotation and here this path variable
allocation is going to sink extract
value of name this mean means is going
to extract value John from this REST API
and assign the same automatically to
student name variable and thereafter
this method what it does it simply goes
to the database such as the complete
information about this student from the
database creates this whole student
object using that information and then
we return the same as a response so
because of this response body annotation
Spring Framework is not going to make
use of any view technology instead it's
going to return the dual value of this
function directly to the client so what
is going to happen after you have
included this controller method then
let's check that out
so here now I'm expecting when I am
going to make a cat request I would get
the information about only this student
not all students information cool it's
happening see so when I made a request
using the name you know John at the end
of this St API spring MVC framework made
a call to this controller method which
made use of pot
variable annotation to extract the value
of you know this mean what I put over
here and then accordingly this body of
controller method prepared the response
and sent to me so that in this tutorial
we cried understanding how to allow a
client to specify a value within the
REST API itself and how to extract that
value in the REST API controller method
using parks variable annotation and
using this whole concept we learned how
to allow a client to retrieve a single
student record right so so far in this
race series we have understood how to
allow a client to request for all
students record and how to allow a
client to retrieve only a single student
record in the next tutorial we are going
to talk about what exactly is the
purpose of rest controller annotation as
well as we're going to look at an
important REST API testing tool known
with the name postman all right
guys a big thank you for learning REST
API concepts using spring MVC framework
with me if you have any feedback or any
constructive comment please put them
below the video or simply email using
this ID if you really liked this video
please hit the like button and don't
forget to subscribe to my youtube
channel gone to CD and I'm going to
catch you in the next one of this to do