In this session, let us learn how to create a spring MVC application using Spring Boot. I'm going to do this in two parts. In part one, let us see the workflow in part two. Let us do the coding I have listed out the workflow of creating a spring MVC application using Spring Boot. First you need to create a Spring Boot application using spring starter project. You need to select the dependencies with the packaging should be what once the application is created, you will be adding two files.

One application class with public static void Main with a direct Spring Boot application as annotation. One other class which extends Spring Boot servlet initializer. So these are the two classes. Now when you run this application, what will be the workflow the class that is annotated with spring boot application will bootstrap your application, you are going to use only external Tomcat server. When the application is bootstrap the web application context gets instantiated. This is the spring container.

This invokes the dispatcher servlet. Now, that dispatcher servlet will map the request to the appropriate controller, whatever URL you have given that URL will be mapped to the appropriate method by the dispatcher servlet based on de Haan using the handler mapping classes, while doing I will explain it. So what is a controller a controller is just a class which is annotated with at the rate controller. From the controller only you will be calling all the other layers the service layer, the service calling the DA vo layer and so on. Now, the controller Getting the data from the backend, the controller has to send it to a view the controller we attach it to an attribute and send it to the view. The controller is not going to view the data directly, but it is going to call the view name.

So, the controller is attaching the data and sending it back back to the dispatcher servlet based on the name given by the controller, the dispatcher servlet has to identify the appropriate view for this the dispatcher servlet will read the properties file from Spring Boot, in that as you are having application dot properties file, wherein you will be specifying what type of view resolver you are using and what is the view framework you are using. Whether you are using JSP or time leaf or velocity based on that the corresponding view will be invoked by the dispatcher servlet So, dispatcher servlet only is responsible for identifying the components and identifying the view. Now, let us discuss the steps one by one. I told you there will be two classes one class was public static void Main which is annotated with that rich Spring Boot application, one other class which extends Spring Boot servlet initializer class and in this class automatically this configure method will be overridden.

What is the purpose of overriding this configure method? It is used to configure your application so that it behaves like a web application when it is slashed by the container Tomcat server Tomcat container this should be identified as a web application and you must get the var file. For this purpose only your class should extend Spring Boot servlet initially sir. Now you'll see I'm what I have done is I'm annotating this class with Spring Boot applications. There is one other class already with public static void Main. We don't need that collection diverse.

You can have one application class which extends Spring Boot servlet initializer. Having this method annotated with Spring Boot application, you don't need any other class while doing the program I will explain it. Next, create a class which is annotated with at the rate controller. Then within which I'm having one method greet message message. This method is annotated with at the rate request mapping. What does this greet this is nothing but the URL.

The dispatcher servlet will map the URL which is there in the view to this particular method. For that only we are using handler mapping classes. This is basically the routing. If somebody is calling from the JSP page using slack grades automatically entered into this method. Here I have used model map What does model map it is just a class which is used for accepting attributes and sending it to a view page. Here using model map, I'm adding an attribute and I'm sending it to the next page.

Next, I am returning success, what is whether it is a string, it is just the name of the view page. So, how exactly the dispatcher servlet will identify that this is a view page based on the properties file. So, in the controller, you are creating your model which has to be sent to the next view page, the view page name is success dot whatever framework you are using. Now, similar to model map, we also have model and model view. What are they model is an interface model map is a class model and view is a class are these are used for sending out providing attributes for a view if you want the in when you're working with data So, let you attach data to a request or a session using session dot set attribute or request attribute. Similarly in spring, if you want to send data to a view you can use any one of this in case of model you are just sending one data in case of model map you can send collection of data to a view in case of modern and view it is a combination of both model and view.

So, using a single return you are giving the model name sorry you are giving the view name the data that has to be sent to the view. Okay, I will just show you by doing the example. Now the controller is done, the dispatcher has served has got their name that the controller is returning this is success. How would you identify which view resolver you're using, it will go to the application dot properties file. In the applications or properties file you are using spring dot MVC dot view dot prefix and So, suffix, what is the meaning of it, it is going to identify what resolver you are using you are as of now using internal resource view resolver because only for this you have to give the prefix and suffix these are properties for this particular class dispatcher servlet will go to this particular application properties file, then it will take the path slash web by enough slash views.

What is the name that I have got from the servlet success? It'll add that success. So, for this name, it is adding prefix adding suffix what is the suffix dot JSP the memory of add the slash also. So, that dispatcher servlet is just taking the name and adding Prefix and Suffix to this particular name. Now, I have got the full path slash we're by no means actually this one with that In our case, he saw that it was web content here, this web web app, because we are using Maven. So, the dispatcher servlet will go in search of success dot JSP within whereby enough views folder, so you need to create all the structure and keep it ready.

So now let me just show you that I have to create a JSP page inside the bat whereby enough useful that these two will not be there you need to create it and your to create the success dot JSP page in the JSP page, how to retrieve it, you can use expression language. So here Here I have used expression language, dollar message, whatever I have passed from the controller, that model data can be retrieved in this particular page. So this is the workflow of a spring MVC application using Spring Boot. What are the classes you need? Because you're working with spring boots, you need an application class. Just annotated with Spring Boot application, then you need a controller then you need this JSP page which is going to show you the final result how to reach the controller, you can reach the controller directly and you can have one other JSP page which will be invoked first that is in our case we can have index dot JSP So, the workflow is something like this from index dot JSP it will go to the controller from the controller it is come back to success dot JSP.

So, I have explained everything clearly in the next session we will do the coding part. Thank you