Difference Between @Controller And @RestController In Spring Boot

Introduction:#

In Spring Boot, @Controller and @RestController annotations are used in Spring MVC for handling HTTP requests.

Annotations in Spring Framework and Java: Annotations provide a couple/bunch of codes that are already in-built. Annotations help configure beans, services, controllers, transactions, validations, and much more. Annotations are special metadata. It helps to reduce the code repetition.

• Less XML configuration: The application becomes more intuitive and cleaner.
• Automatic Configuration: Spring Boot automatically detects and configures beans with annotations.
• Simplified Dependency Injection: Annotations like @Autowired eliminating manual wiring.

@Controller:#

In Spring MVC, @Controller is used to create web-based applications that return views (HTML, JSP, Thymeleaf, etc.). It is typically used for handling UI-based requests. Requires @ResponseBody if you want to return JSON or XML instead of a view. It is used when building traditional web applications with templates (Thymeleaf, JSP).

@Controller
public class WebController {

    @GetMapping("/home")
    public String homePage() {
        return "home"; // Returns "home.html" or "home.jsp" from templates
    }

    @GetMapping("/json")
    @ResponseBody // Needed to return JSON
    public Map<String, String> getJson() {
        return Map.of("message", "Hello from Controller");
    }
}

@RestController:#

In Spring MVC, it is a combination of @Controller and @ResponseBody, meaning every method automatically returns JSON or XML data. Used when building REST APIs instead of serving web pages. It is used when creating REST APIs that return JSON/XML.

@RestController
public class ApiController {

    @GetMapping("/api/data")
    public Map<String, String> getData() {
        return Map.of("message", "Hello from RestController");
    }
}

Difference Between @Controller And @RestController In Spring Boot:#

Conclusion:#

We learned that the @Controller is used for handling web requests that return views in MVC applications, and Spring, @RestController is designed for building RESTful APIs that return data in formats like JSON or XML. Understanding these distinctions helps you choose the right annotation for your application needs.