Setting JSON Content Type in Spring MVC

How to Set JSON Content Type In Spring MVC

Setting the JSON content type in Spring MVC is essential when developing API-centric applications. The type of content returned from an API can drastically affect the effectiveness and usability of your application. Over the years, JSON has become the de facto standard for data exchange between web applications, making it necessary for any API to deliver data in this format.

In this tutorial, we’ll take a look at how to set the Content-Type header to application/json in a Spring MVC application. We’ll also look at how to configure the response body with a custom JSON serializer.

Spring MVC JSON Configuration

The Spring MVC framework provides a number of support classes to help you easily configure your application to handle requests containing a variety of different content types. This includes the ability to set the JSON content type on all responses returned by your application.

To do this, create a new class that implements the org.springframework.web.servlet.config.annotation.WebMvcConfigurer interface. This interface provides access to a number of methods that allow you to customize the way Spring MVC applications are configured.

To set the Content-Type header to application/json, override the addContentNegotiationViewResolver method with the following code:

@Override
    public void addContentNegotiationViewResolver(ContentNegotiationConfigurer configurer) {
        configurer.defaultContentType(MediaType.APPLICATION_JSON_VALUE);
    }

This will ensure all responses from your application have the Content-Type header set to application/json.

Customizing the JSON Response

In addition to setting the Content-Type header to application/json, you may also need to customize the way the response body is formatted. This can be done by creating a custom JSON serializer.

To do this, create a new class that implements the org.springframework.http.converter.HttpMessageConverter interface. This interface provides access to a number of methods that allow you to customize the way responses are formatted as JSON.

To use this custom serializer, register it with the Spring MVC framework by overriding the configureMessageConverters method with the following code:

@Override
    public void configureMessageConverters(List<HttpMessageConverter> converters) {
        converters.add(new CustomJsonSerializer());
    }

This will ensure all responses from your application are serialized using your custom serializer.

Conclusion

In this tutorial, we took a look at how to set the JSON content type in a Spring MVC application. We also looked at how to configure the response body with a custom JSON serializer. By following these steps, you can ensure your application is delivering the best possible data to its users.