10 Spring MVC Interview Questions and Answers in 2023
1. Describe the architecture of a Spring MVC application.
The architecture of a Spring MVC application is based on the Model-View-Controller (MVC) design pattern. It is a web application framework that uses the MVC pattern to separate the application’s data model, business logic, and presentation layer.
At the core of the Spring MVC architecture is the DispatcherServlet. This servlet is responsible for receiving all incoming requests and dispatching them to the appropriate controller. The controller is responsible for handling the request and returning a ModelAndView object. The ModelAndView object contains the model data and the view name.
The view name is then used to resolve the view. The view is responsible for rendering the model data and returning the response to the client.
The model data is typically stored in a database and is accessed through a data access layer. This layer is responsible for retrieving and persisting the data.
The Spring MVC architecture also supports the use of interceptors. Interceptors are used to intercept requests and perform pre-processing and post-processing tasks.
Finally, the Spring MVC architecture also supports the use of validators. Validators are used to validate the data before it is processed by the controller.
2. What is the purpose of the DispatcherServlet in Spring MVC?
The DispatcherServlet is the front controller in Spring MVC. It is responsible for receiving all incoming requests and dispatching them to the appropriate controller for processing. It is also responsible for resolving views and rendering the response. It is the central entry point for all requests into the Spring MVC application. It is responsible for loading the Spring application context and delegating requests to the appropriate controller. It also provides support for internationalization, view resolution, and exception handling. The DispatcherServlet is the heart of the Spring MVC framework and is essential for any Spring MVC application.
3. How do you configure a Spring MVC application?
Configuring a Spring MVC application involves several steps.
1. Create a web.xml file. This file is used to define the servlet container and the servlet mapping. It also defines the context parameters and the listeners.
2. Create a Spring configuration file. This file is used to define the beans and the configuration of the application. It also defines the view resolvers, the interceptors, and the message sources.
3. Create a DispatcherServlet. This servlet is responsible for dispatching requests to the appropriate controller. It also handles the view resolution and the exception handling.
4. Create the controllers. The controllers are responsible for handling the requests and returning the appropriate response.
5. Create the views. The views are responsible for rendering the response.
6. Configure the view resolvers. The view resolvers are responsible for resolving the view name to the appropriate view.
7. Configure the interceptors. The interceptors are responsible for intercepting the requests and performing the necessary operations.
8. Configure the message sources. The message sources are responsible for providing the localized messages.
9. Configure the static resources. The static resources are responsible for serving the static content such as images, CSS, and JavaScript.
10. Configure the filters. The filters are responsible for filtering the requests and responses.
11. Configure the security. The security is responsible for providing the authentication and authorization.
12. Configure the logging. The logging is responsible for logging the requests and responses.
13. Configure the database. The database is responsible for providing the data access layer.
14. Configure the testing. The testing is responsible for testing the application.
15. Deploy the application. The application is deployed to the servlet container.
4. What is the difference between @Controller and @RestController annotations?
The @Controller and @RestController annotations are both used in Spring MVC to mark a class as a controller. The main difference between the two is that the @RestController annotation is used to create RESTful web services while the @Controller annotation is used to create traditional MVC controllers.
The @RestController annotation is a combination of the @Controller and @ResponseBody annotations. It is used to create a controller that returns a response body. This means that the response body is automatically serialized to JSON or XML and returned to the client.
The @Controller annotation is used to create a controller that returns a view. This means that the controller will return an HTML page or a template that can be rendered by the client.
In summary, the @Controller annotation is used to create traditional MVC controllers while the @RestController annotation is used to create RESTful web services.
5. How do you handle exceptions in Spring MVC?
When working with Spring MVC, exceptions can be handled in a few different ways.
The first way is to use the @ExceptionHandler annotation. This annotation can be used to map an exception to a specific handler method. The handler method can then be used to return a response with an appropriate status code and message. This is a great way to handle exceptions in a centralized way, as all exceptions can be handled in one place.
The second way to handle exceptions is to use the @ControllerAdvice annotation. This annotation can be used to create a global exception handler. This handler can be used to catch any exceptions that are thrown in the application and return a response with an appropriate status code and message.
The third way to handle exceptions is to use the @ResponseStatus annotation. This annotation can be used to map an exception to a specific HTTP status code. This is a great way to handle exceptions in a more granular way, as each exception can be mapped to a specific status code.
Finally, the fourth way to handle exceptions is to use the @ControllerAdvice and @ExceptionHandler annotations together. This allows for a more granular approach to exception handling, as each exception can be mapped to a specific handler method. This allows for more control over the response that is returned for each exception.
Overall, Spring MVC provides a variety of ways to handle exceptions. Depending on the needs of the application, any of these approaches can be used to ensure that exceptions are handled in an appropriate manner.
6. What is the purpose of the ModelAndView class in Spring MVC?
The ModelAndView class in Spring MVC is a class used to combine the model and view components of a web application. It is used to represent the model data and the view technology that will be used to render the response. The ModelAndView class is used to pass data from the controller to the view layer. It is also used to specify the view name that will be used to render the response. The ModelAndView class is a convenient way to combine the model and view components of a web application into a single object. It allows the controller to pass data to the view layer in a single object, rather than having to pass multiple objects. The ModelAndView class also allows the controller to specify the view name that will be used to render the response. This makes it easier to maintain the application, as the view name can be changed without having to modify the controller code.
7. How do you configure view resolvers in Spring MVC?
Configuring view resolvers in Spring MVC is a relatively straightforward process. The first step is to create a ViewResolver bean in the Spring configuration file. This bean will be responsible for resolving views based on the view name. The bean can be configured with a variety of properties, such as the prefix and suffix of the view name, the order in which the resolvers should be applied, and the view class to be used.
Once the ViewResolver bean is configured, it can be registered with the Spring MVC DispatcherServlet. This is done by adding the ViewResolver bean to the list of view resolvers in the DispatcherServlet configuration.
Finally, the view resolvers can be tested by creating a controller that returns a view name. The view name should be the same as the view name configured in the ViewResolver bean. When the controller is invoked, the DispatcherServlet will use the configured view resolvers to resolve the view name and render the view.
8. What is the purpose of the @RequestMapping annotation?
The @RequestMapping annotation is used in Spring MVC to map a request to a specific handler method. It is used to map a URL pattern to a controller method, which is then used to handle the request. The annotation can be used to map a single request, or multiple requests, to a single handler method. It can also be used to map requests to different handler methods based on the HTTP method used (e.g. GET, POST, PUT, etc.). The annotation can also be used to map requests to different handler methods based on the request parameters, headers, and other request attributes. Additionally, the annotation can be used to map requests to different handler methods based on the content type of the request. Finally, the annotation can be used to map requests to different handler methods based on the request path.
9. How do you configure a Spring MVC application to use RESTful web services?
Configuring a Spring MVC application to use RESTful web services is a straightforward process.
First, you need to add the Spring MVC dependency to your project. This can be done by adding the following dependency to your pom.xml file:
Next, you need to create a configuration class that will enable Spring MVC to use RESTful web services. This class should be annotated with @Configuration and should extend WebMvcConfigurationSupport. In this class, you should enable the annotation-driven configuration by overriding the addResourceHandlers() method and adding the following line:
registry.addResourceHandler("/rest/**").addResourceLocations("/rest/");
Finally, you need to create a controller class that will handle the requests for the RESTful web services. This class should be annotated with @RestController and should contain methods annotated with @RequestMapping. These methods should be used to handle the requests for the RESTful web services.
By following these steps, you can configure a Spring MVC application to use RESTful web services.
10. How do you configure a Spring MVC application to use Hibernate?
To configure a Spring MVC application to use Hibernate, the following steps should be taken:
1. Add the necessary dependencies to the project's pom.xml file. This includes the Hibernate core library, the Hibernate entity manager library, and the Spring ORM library.
2. Create a Hibernate configuration file (hibernate.cfg.xml) and specify the database connection details, such as the database URL, username, and password.
3. Create a Hibernate mapping file (hibernate.hbm.xml) and specify the mapping between the Java classes and the database tables.
4. Create a Spring configuration file (applicationContext.xml) and specify the Hibernate configuration and mapping files.
5. Create a DataSource bean in the Spring configuration file and specify the database connection details.
6. Create a SessionFactory bean in the Spring configuration file and specify the DataSource bean.
7. Create a TransactionManager bean in the Spring configuration file and specify the SessionFactory bean.
8. Create a HibernateTemplate bean in the Spring configuration file and specify the SessionFactory bean.
9. Create a DAO bean in the Spring configuration file and specify the HibernateTemplate bean.
10. Inject the DAO bean into the Spring MVC controller.
11. Use the DAO bean to access the database.