Key Components of Spring MVC Architecture

Key Components of Spring MVC Architecture

Spring MVC Architecture follows the Model-View-Controller (MVC) design pattern and has several key components that work together to handle web requests and responses efficiently. Below are the primary components:

1. DispatcherServlet

   Acts as the front controller in the Spring MVC architecture. It intercepts all incoming requests and delegates them to the appropriate controller.

2. Handler Mapping:

   Maps incoming requests to appropriate handler methods of the controllers.

3. Controller

   Contains the business logic and interacts with the model. It processes user requests and returns a view name.

4. Model

   Represents the application data. The controller can add data to the model, which is then accessible by the view.

5. View:

   Responsible for rendering the model data. It can be a JSP, Thymeleaf template, or any other view technology.

6. View Resolver:

   Resolves view names to actual view pages.

7. ModelAndView:

   A container object that holds both the model data and the view name.

Spring MVC Architecture

Project Structure
Java Examples
 1. Project Structure
```
src
 └── main
     └── java
         └── com
             └── example
                 └── config
                     └── WebConfig.java
                 └── controller
                     └── HomeController.java
     └── resources
         └── application.properties
     └── webapp
         └── WEB-INF
             └── views
                 └── home.jsp
     └── web.xml
```

Maven Dependencies (pom.xml)
 2. Maven Dependencies (pom.xml)
```xml
<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.10</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
        <scope>provided</scope>
    </dependency>
</dependencies>
```

Web Configuration (WebConfig.java)
 3. Web Configuration (WebConfig.java)
```java
package com.example.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ViewResolverRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.example.controller")
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
        registry.jsp("/WEB-INF/views/", ".jsp");
    }
}
```

Controller (HomeController.java)
 4. Controller (HomeController.java)
```java
package com.example.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;

@Controller
public class HomeController {

    @GetMapping("/")
    public String home(Model model) {
        model.addAttribute("message", "Hello, Spring MVC!");
        return "home"; // returns the view name "home"
    }
}
```

View (home.jsp)
 5. View (home.jsp)
```jsp
<!DOCTYPE html>
<html>
<head>
    <title>Home</title>
</head>
<body>
    <h1>${message}</h1>
</body>
</html>
```

web.xml Configuration
6. web.xml Configuration
```xml
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" 
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
         http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" 
         version="4.0">
    
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/spring/dispatcher-config.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

Homepage

Readmore