Difference between Spring @Controller and @RestController annotation

java

spring

annotation

restful-services

byNikita Barsukov·Jan 6, 2025

In Spring, @Controller & @RestController serve unique purposes. The former is primarily for web applications, returning view templates, whereas the latter is perfect for RESTful web services, promptly returning object data formatted as JSON or XML.

For @Controller, you'd typically return a ModelAndView. Think of it as a courier delivering a package (view) to your door:

@Controller
public class WebController {
    @GetMapping("/greeting")
    // So, you're delivering greetings now? 😄
    public ModelAndView greet() {
        // Special delivery, coming right up! 🎁
        return new ModelAndView("greetView");
    }
}

On the other hand, with @RestController, methods return data objects, conveniently auto-serialized into JSON/XML:

@RestController
public class ServiceController {
    @GetMapping("/user")
    // Knock-knock. Who's there?... It's Alice! 👋
    public User getUser() {
        // Alice, our loyal user. Let's give her data! 📂
        return new User("Alice");
    }
}

Choosing between @Controller and @RestController

When dealing with response type and your application needs, your choice between @Controller and @RestController becomes crucial. If you're tackling a traditional web application, where the server-side is rendering the page, then @Controller is your star player. However, if you're venturing into the world of API development with RESTful services, where the data is often supplied to non-browser clients, you'd want to recruit @RestController on your team.

@RestController - not just a @Controller

Yes, @RestController is actually @Controller on steroids. It's a convenience annotation that rolls @Controller and @ResponseBody into one. This means that the return value of the mapped method is sent directly into the response body, not interpreted as a view name.

Here's a simple mnemonic:

Recruit @RestController for your RESTful web services where sending JSON or XML responses swiftly is paramount.
Stick with @Controller if you're knee deep in dynamic page rendering with server-side templates like Thymeleaf or JSP.

The added magic of @RestController

Taking @Controller a notch higher, @RestController saves you from the repetitive task of annotating each handler method with @ResponseBody when your endgame is creating a RESTful service. A win for code brevity and maintenance!

Using Views with REST: the @Controller way

In a Web MVC environment, @Controller is a crowd favorite. However, to return data instead of a view, you need to pair the handler methods with @ResponseBody, signalling to Spring that the return type should be written as-is into the HTTP response body.

RESTful service with @RestController

Run a REST API like a boss with @RestController - no @ResponseBody necessary on individual handler methods. Free from nuisances of view-related configurations, @RestController allows you to focus on designing your REST API's endpoints.

Embracing advanced scenarios

Async processing in Spring MVC applications? No problem. Both @Controller and @RestController have got your back. They can handle asynchronous request processing by returning Callable or DeferredResult. This is especially handy when managing long-running tasks in your REST APIs.

Working with HTTP Requests

Wondering about dealing with custom headers or status codes? @Controller & @RestController can easily leverage the @ResponseStatus and @RequestHeader for this. To handle request entities, you've got @RequestBody on your side, able to retrieve the body of the HTTP request, regardless of your choice of annotation.

Considering security

Both @Controller and @RestController work harmoniously with Spring Security. When binding @RestController with REST APIs, remember to consider statelessness and usage of tokens like JWT for authentication as it's the norm in RESTful architecture.

The importance of proactive learning

Check the latest Javadoc and Spring guides regularly! Understanding subtle differences and updates related to these annotations is key as Spring evolves frequently. Keeping yourself updated ensures you're using the best practices and remain in sync with the latest Spring framework’s offerings.

Customising your approach

For global exception handling and data binding customizations across the whole application or for specific packages or controllers, consider integrating with the advice mechanisms such as @ControllerAdvice or @RestControllerAdvice.

explain-codes / Java / Difference between Spring @Controller and @RestController annotation

Linked

Spring Boot: Cannot access REST Controller on localhost (404)



Spring MVC - How to get all request params in a map in Spring controller?



Trigger 404 in Spring-MVC controller?



What's the difference between @Component, @Repository & @Service annotations in Spring?



What is Dispatcher Servlet in Spring?

