Swagger 2 accept xml instead of json

Question

I have a project with spring boot and I want to use swagger2 to document my json web services.

I have this configuration :

@Configuration
@EnableSwagger2
public class Swagger2Config {

@Bean
public Docket welcomeMessageApi() {
    return new Docket(DocumentationType.SWAGGER_2)
            .apiInfo(apiInfo())
            .select()
            .apis(RequestHandlerSelectors.any())
            .paths(PathSelectors.any())
            .build();
}

private ApiInfo apiInfo() {
    return new ApiInfoBuilder()
            .title("My API")
            .description("Lorem Ipsum is simply dummy text of ...")
            .termsOfServiceUrl("an url")
            .contact("contact")
            .license("")
            .licenseUrl("")
            .version("2.0")
            .build();
}

To read the documentation, I use this link : http://localhost:9081/v2/api-docs

In the swagger UI, it works fine. But when I try this link directly in my browser, I have this error :

With Firebug, I see that it accept XML content instead of JSON content.

How can I modify swagger configuration to accept JSON content ?

Answer 1

You meet the problem because of the Spring MVC default get the server to render XML instead of JSON in a browser. The official document say:

To get the server to render XML instead of JSON you might have to send an Accept: text/xml header (or use a browser).

So all you need to do is make the server render JSON in browser.

When you deep into the request in browser you'll see the Request Header:

Accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8

And if you debug into the spring boot, you will see the spring mvc will default delegate HttpMessageConverters include MappingJackson2XmlHttpMessageConverter and MappingJackson2HttpMessageConverter.

The MappingJackson2HttpMessageConverter is to render json and MappingJackson2XmlHttpMessageConverter is to render xml.

They both have a field supportedMediaTypes which means what mediatypes are supported.

The value of supportedMediaTypes in MappingJackson2HttpMessageConverter is:

The value of supportedMediaTypes in MappingJackson2XmlHttpMessageConverter is:

There is a 'text/xml;charset=UTF-8' in MappingJackson2XmlHttpMessageConverter.This is why browser render xml instend of json.

So you need add a custom MappingJackson2XmlHttpMessageConverter which support 'text/xml', for example :

    @Configuration
public class WebConfig extends WebMvcConfigurerAdapter {
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
        List<MediaType> list = new ArrayList<>();
        list.add(MediaType.APPLICATION_JSON_UTF8);
        list.add(new MediaType("text", "html", Charset.forName("UTF-8")));
        list.add(new MediaType("application", "*+json", Charset.forName("UTF-8")));
        converter.setSupportedMediaTypes(list);
        converters.add(converter);
    }
}

Try this and browser will render JSON instead of XML in browser, and all things right!

Answer 2

What worked for me was updating the Maven dependencies for springfox-swagger2 and springfox-swagger-ui.

The newest working combination for me was:

    <!-- https://mvnrepository.com/artifact/io.springfox/springfox-swagger2 -->
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
        <version>2.8.0</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/io.springfox/springfox-swagger-ui -->
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger-ui</artifactId>
        <version>2.9.2</version>
    </dependency>