Introduction to Spring MVC

Spring MVC (Model-View-Controller) is an implementation of the Model-View-Controller pattern defined in the Java EE specification, built upon the Servlet API. As one of the most core web modules within the Spring framework, it provides a lightweight, non-intrusive solution for web application development. Unlike the traditional JSP + Struts2 architecture, Spring MVC decouples the Controller layer from the View, enabling developers to handle business logic and page rendering more flexibly. Its core design philosophy revolves around managing view navigation through "declarative" programming while maintaining full compatibility with the underlying Servlet API, thereby simplifying the development process while ensuring system scalability.
The workflow of Spring MVC follows the standard request-response model, primarily comprising a Controller, Service layer, and Data Access Object (DAO). When a user initiates an HTTP request, the browser sends it to the web container (such as Tomcat). Upon receiving the request, the web container forwards it to the Spring DispatcherServlet. Subsequently, acting as the core of the front controller, the DispatcherServlet is responsible for dispatching requests to specific Controller methods to handle business logic, finally returning the result to the view layer for presentation to the user.

The core components of Spring MVC include:

Controller: Responsible for receiving HTTP requests, invoking business logic in the Service layer, and ultimately deciding on the View to be rendered or the return type (such as JSON or XML).
DispatcherServlet: Serving as the front controller, it coordinates various components to complete the entire request processing flow.
ViewResolver: Used to resolve view names into specific physical paths, enabling flexible configuration of views.

Core Annotations and Functional Features of Spring MVC

Spring MVC provides a wealth of annotations to simplify the development process, with @Controller, @RequestMapping, and @ResponseBody being among the most commonly used. These annotations allow developers to define request mappings and business logic in a declarative manner, thereby reducing the amount of boilerplate code required. For instance, using @GetMapping("/users") concisely defines a GET request handler; while @RestController is a simplified version that merges Controller with ResponseBody, often used for building RESTful API services.

In addition, Spring MVC supports advanced features such as parameter binding, model data setting, and exception handling. Developers can pass additional attribute information to the view using the @ModelAttribute annotation, utilize @ExceptionHandler to capture and uniformly handle business exceptions, thereby enhancing code maintainability and robustness. These features collectively form the strong foundation of Spring MVC's development capabilities.

Practical Example: Building a Simple User List Interface

To better understand the application scenarios of Spring MVC, here is a simple implementation example of a user list API based on Maven + Spring Boot. First, create the Controller class UserController, defining two core methods to handle GET and POST requests respectively:

package com.example.demo.controller;

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

@Controller
public class UserController {

    @GetMapping("/users")
    public String listUsers(Model model) {
        // Simulate fetching user data from the database and passing it into the Model
        model.addAttribute("userList", java.util.Arrays.asList(
            new User("Alice"), 
            new User("Bob")));
        
        return "user-list"; // Returns the view name, which is resolved to an actual path by the ViewResolver
    }

    @PostMapping("/users/add")
    public String addUser(@RequestParam String name, Model model) {
        // Handle the logic for adding a new user (specific implementation omitted here)
        model.addAttribute("message", "User added successfully");
        return "user-form";
    }
}

In this example, the @GetMapping("/users") method is responsible for rendering the user list page and encapsulating the data into the Model; meanwhile, @PostMapping("/users/add") handles the form submission logic. This design pattern with clear structure and separation of responsibilities is precisely where Spring MVC shines. By configuring the viewResolver (typically located in application.properties), we can easily specify the view prefix and suffix, for example, setting the prefix to /WEB-INF/views/ and the suffix to .jsp, thus achieving decoupling from backend code.

Summary: The Position of Spring MVC in Modern Web Development

Although microservice architectures and frontend-backend separation models have become increasingly popular in recent years, Spring MVC remains an ideal choice for building traditional monolithic applications, rapid prototype systems, and complex backend management systems. With its mature ecosystem, flexible configuration capabilities, and extensive community support, it continues to provide stable and reliable solutions for Java developers. Whether used for internal management systems or externally provided RESTful APIs, Spring MVC helps teams efficiently complete the entire development loop from business logic to final presentation. With the rise of Spring Boot, its integration complexity has further decreased, allowing beginners to quickly get started with building production-grade web applications.