Difference Between Controller and RestController

Difference Between Controller and RestController

3 mins readComment
Esha
Esha Gupta
Associate Senior Executive
Updated on Mar 29, 2024 18:20 IST

Controller is a Spring annotation used for web applications to map HTTP requests to view names, requiring ResponseBody for methods returning data. RestController simplifies RESTful service creation by combining Controller and ResponseBody, automatically serializing method return values into JSON or XML for the client. Let's understand more!

A Controller is primarily used for traditional web applications where the controller's role is to return a view. It is suited for applications that require rendering HTML templates. On the other hand, RestController is a specialized version of Controller designed specifically for building RESTful web services. In this blog, we will understand the differences between them in detail!

Table of Content

Difference Between Controller and RestController

Below is a table of differences between controller and restcontroller.

Aspect

@Controller

@RestController

Annotation Type

A stereotype annotation used in Spring MVC to define a controller component.

A convenience annotation that is itself annotated with @Controller and @ResponseBody.

Purpose

Primarily used for traditional web applications to return a view.

Used for building RESTful web services, returning data in JSON or XML format.

ResponseBody

Requires @ResponseBody annotation on the method to serialize the return object to the HTTP response body.

Automatically serializes return objects to the HTTP response body because it includes @ResponseBody.

View Resolution

Supports view resolution, allowing for returning a view name which will be resolved by a ViewResolver.

Does not support view resolution. Designed to return data directly to the client.

Use Case

Suited for applications that return HTML or JSP pages.

Suited for API development where the response is data (e.g., JSON, XML).

Content Type

Can produce any type of content, including HTML, but requires explicit annotation to return data as JSON or XML.

Primarily produces JSON or XML responses.

Headers

You have to manually add @ResponseBody for it to include relevant headers indicating the type of response.

Automatically handles and includes headers indicating the type of response (e.g., application/json).

 

What is a Controller?

A controller is a component or class that handles client requests, processes them (often with the help of models), and determines the response to send back, such as data or a view. It acts as an intermediary between the model (data) and the view (presentation layer).

Mind Map:

What is a RestController?

A RestController is a specialized annotation in the Spring Framework used primarily for developing RESTful web services. It combines the functionality of Controller and ResponseBody annotations, simplifying the creation of controllers that return data directly to the client.

Mind Map:

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FAQs

Can I use @Controller to build a REST API?

Yes, you can use @Controller to build a REST API, but it requires that each method intended to return a response body be explicitly annotated with @ResponseBody. Without @ResponseBody, Spring MVC will interpret the method’s return value as a view name to be resolved, not as data to be written directly to the body of the response. This means extra annotation work compared to using @RestController, which automatically assumes @ResponseBody behavior for all controller methods.

Why would I choose @RestController over @Controller for a web application?

@RestController is specifically designed for services where the response is data (JSON or XML) rather than a rendered view. It simplifies the development of RESTful web services by automatically applying @ResponseBody to all controller methods, eliminating the need for additional annotations to serialize return objects into the response body. If your web application primarily serves as an API that clients consume (e.g., for single-page applications, mobile applications), @RestController is the more efficient and clear choice.

How do @Controller and @RestController handle HTTP response headers?

Methods in a class annotated with @Controller that return data directly to the response body must be annotated with @ResponseBody. This approach allows for manual control over the response, including modifying HTTP headers if needed. On the other hand, @RestController combines @Controller and @ResponseBody annotations, which means it automatically serializes the return value to the HTTP response body and handles HTTP headers accordingly, primarily focusing on content type (like application/json). For both annotations, further customization of the response, including headers, can be achieved by returning a ResponseEntity object, allowing for comprehensive control over the response status, headers, and body.

About the Author
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Esha Gupta
Associate Senior Executive

Hello, world! I'm Esha Gupta, your go-to Technical Content Developer focusing on Java, Data Structures and Algorithms, and Front End Development. Alongside these specialities, I have a zest for immersing myself in v... Read Full Bio