Spring – MVC Framework
Spring MVC Framework follows the Model-View-Controller design pattern. It is used to develop web applications. It works around DispatcherServlet. DispatcherServlet handles all the HTTP requests and responses. It dispatches the requests to handlers. It uses @Controller and @RequestMapping as default request handlers. The @Controller annotation defines that a particular class is a controller. @RequestMapping annotation maps web requests to Spring Controller methods. The terms model, view, and controller are as follows:
- Model: The Model encapsulates the application data.
- View: View renders the model data and also generates HTML output that the client’s browser can interpret.
- Controller: The Controller processes the user requests and passes them to the view for rendering.
Spring MVC Framework works as follows:
- All the incoming requests are intercepted by the DispatcherServlet that works as the front controller.
- The DispatcherServlet then gets an entry of handler mapping from the XML file and forwards the request to the controller.
- The object of ModelAndView is returned by the controller.
- The DispatcherServlet checks the entry of the view resolver in the XML file and invokes the appropriate view component.
Advantages of Spring MVC Framework
- The container is used for the development and deployment of applications and uses a lightweight servlet.
- It enables rapid and parallel development.
- Development of the application becomes fast.
- Easy for multiple developers to work together.
- Easier to Update the application.
- It is Easier to Debug because we have multiple levels in the application.
Disadvantages of Spring MVC Framework
- It has high complexity to develop the applications using this pattern.
- It is not suitable for small applications which affect the application’s performance and design.
Create Your First Spring MVC Application
Consider the following example:
Step 0: Setup your project with maven use the required archtype to get the required folders directory and configure the server with your project.
Step 1: Load the spring jar files or add the dependencies if Maven is used. Add the following dependencies in pom.xml
pom.xml
XML
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 <modelVersion>4.0.0</modelVersion> <groupId>com.javatpoint</groupId> <artifactId>SpringMVC</artifactId> <packaging>war</packaging> <version>0.0.1-SNAPSHOT</version> <name>SpringMVC Maven Webapp</name> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>5.1.1.RELEASE</version> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>3.0-alpha-1</version> </dependency> </dependencies> <build> <finalName>SpringMVC</finalName> </build> </project> |
Step 2: Create the Controller Class
HelloGeek.java
Java
@Controller public class HelloGeek { @RequestMapping("/") public String display() { return "hello"; } } |
Step 3: Provide the name of the controller in the web.xml file as follows:
DispatcherServlet is the front controller in Spring Web MVC. Incoming requests for the HTML file are forwarded to the DispatcherServlet.
web.xml
XML
<?xml version="1.0" encoding="UTF-8"?> xsi:schemaLocation="http://java.sun.com/xml/ns/javaee <display-name>SpringMVC</display-name> <servlet> <servlet-name>spring</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>spring</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app> |
Step 4: We have to define the bean in a separate XML file. We have specified the view components in this file. It is located in the WEB-INF directory.
spring-servlet.xml
XML
<?xml version="1.0" encoding="UTF-8"?> xsi:schemaLocation=" <!-- This element defines the base-package where DispatcherServlet will search the controller class. --> <context:component-scan base-package="com.geek" /> <!--Provide support for conversion, formatting and also for validation --> <mvc:annotation-driven/> </beans> |
Step 5: Use JSP to display the message
index.jsp
HTML
<html> <body> <p>Spring MVC Tutorial!!</p> </body> </html> |
Step 6: Start the server and run the project. The output is displayed as follows:
Spring MVC Tutorial!!
