Spring’s RequestBody and ResponseBody Annotations

Last updated: May 11, 2024

Written by: baeldung

Reviewed by: Zeger Hendrikse

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1. Introduction

In this quick tutorial, we provide a concise overview of the Spring @RequestBody and @ResponseBody annotations.

Guide to Spring Handler Mappings

The article explains how HandlerMapping implementation resolve URL to a particular Handler.

Quick Guide to Spring Controllers

A quick and practical guide to Spring Controllers - both for typical MVC apps and for REST APIs.

The Spring @Controller and @RestController Annotations

Learn about the differences between @Controller and @RestController annotations in Spring MVC.

2. @RequestBody

Simply put, the @RequestBody annotation maps the HttpRequest body to a transfer or domain object, enabling automatic deserialization of the inbound HttpRequest body onto a Java object.

First, let’s have a look at a Spring controller method:

@PostMapping("/request")
public ResponseEntity postController(
  @RequestBody LoginForm loginForm) {
 
    exampleService.fakeAuthenticate(loginForm);
    return ResponseEntity.ok(HttpStatus.OK);
}

Spring automatically deserializes the JSON into a Java type, assuming an appropriate one is specified.

By default, the type we annotate with the @RequestBody annotation must correspond to the JSON sent from our client-side controller:

public class LoginForm {
    private String username;
    private String password;
    // ...
}

Here, the object we use to represent the HttpRequest body maps to our LoginForm object.

Let’s test this using CURL:

curl -i \
-H "Accept: application/json" \
-H "Content-Type:application/json" \
-X POST --data 
  '{"username": "johnny", "password": "password"}' "https://localhost:8080/spring-boot-rest/post/request"

This is all we need for a Spring REST API and an Angular client using the @RequestBody annotation.

3. @ResponseBody

The @ResponseBody annotation tells a controller that the object returned is automatically serialized into JSON and passed back into the HttpResponse object.

Suppose we have a custom Response object:

public class ResponseTransfer {
    private String text; 
    
    // standard getters/setters
}

Next, the associated controller can be implemented:

@Controller
@RequestMapping("/post")
public class ExamplePostController {

    @Autowired
    ExampleService exampleService;

    @PostMapping("/response")
    @ResponseBody
    public ResponseTransfer postResponseController(
      @RequestBody LoginForm loginForm) {
        return new ResponseTransfer("Thanks For Posting!!!");
     }
}

In the developer console of our browser or using a tool like Postman, we can see the following response:

{"text":"Thanks For Posting!!!"}

Remember, we don’t need to annotate the @RestController-annotated controllers with the @ResponseBody annotation since Spring does it by default.

3.1. Setting the Content Type

When we use the @ResponseBody annotation, we’re still able to explicitly set the content type that our method returns.

For that, we can use the @RequestMapping‘s produces attribute. Note that annotations like @PostMapping, @GetMapping, etc. define aliases for that parameter.

Let’s now add a new endpoint that sends a JSON response:

@PostMapping(value = "/content", produces = MediaType.APPLICATION_JSON_VALUE)
@ResponseBody
public ResponseTransfer postResponseJsonContent(
  @RequestBody LoginForm loginForm) {
    return new ResponseTransfer("JSON Content!");
}

In the example, we used the MediaType.APPLICATION_JSON_VALUE constant. Alternatively, we can use application/json directly.

Next, let’s implement a new method, mapped to the same /content path, but returning XML content instead:

@PostMapping(value = "/content", produces = MediaType.APPLICATION_XML_VALUE)
@ResponseBody
public ResponseTransfer postResponseXmlContent(
  @RequestBody LoginForm loginForm) {
    return new ResponseTransfer("XML Content!");
}

Now, depending on the value of an Accept parameter sent in the request’s header, we’ll get different responses.

Let’s see this in action:

curl -i \ 
-H "Accept: application/json" \ 
-H "Content-Type:application/json" \ 
-X POST --data 
  '{"username": "johnny", "password": "password"}' "https://localhost:8080/spring-boot-rest/post/content"

The CURL command returns a JSON response:

HTTP/1.1 200
Content-Type: application/json
Transfer-Encoding: chunked
Date: Thu, 20 Feb 2020 19:43:06 GMT

{"text":"JSON Content!"}

Now, let’s change the Accept parameter:

curl -i \
-H "Accept: application/xml" \
-H "Content-Type:application/json" \
-X POST --data
  '{"username": "johnny", "password": "password"}' "https://localhost:8080/spring-boot-rest/post/content"

As anticipated, we get an XML content this time:

HTTP/1.1 200
Content-Type: application/xml
Transfer-Encoding: chunked
Date: Thu, 20 Feb 2020 19:43:19 GMT

<ResponseTransfer><text>XML Content!</text></ResponseTransfer>

4. Conclusion

We’ve built a simple Angular client for the Spring app that demonstrates how to use the @RequestBody and @ResponseBody annotations.

Additionally, we showed how to set a content type when using @ResponseBody.

The code backing this article is available on GitHub. Once you're logged in as a Baeldung Pro Member, start learning and coding on the project.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

Try a 14-Day Free Trial of Orkes Conductor today.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

Try a 14-Day Free Trial of Orkes Conductor today.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.