SpringMVC with OpenAPI 3.0 and Swagger

[ctapobep]

Here's a setup of Swagger with Spring MVC without Spring Boot. Note that Swagger had its static resources in a different folder in previous versions (before version 3.0.0).

Maven

    <dependency>
      <groupId>io.springfox</groupId>
      <artifactId>springfox-swagger2</artifactId>
      <version>3.0.0</version>
    </dependency>
    <dependency>
      <groupId>io.springfox</groupId>
      <artifactId>springfox-swagger-ui</artifactId>
      <version>3.0.0</version>
    </dependency>

Serving Swagger requests right from our app

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

import static springfox.documentation.builders.PathSelectors.ant;

@Configuration
// Too much to dig through the code if we go w/o this annotation - it does package-scan and imports other
// contexts that do package-scan too. On top of that there's an auto-configuration which depends on the
// presence of other entities. It's just ugh, you can't easily figure out what's actually initialized.
// Kids, don't write libraries like Swagger team - code must be simple and explicit!
@EnableSwagger2
class SwaggerConfig {

    /**
     * Swagger creates an endpoint that returns JSON with all the info about our API that it deduced from
     * SpringMVC. This doesn't yet handle HTML/CSS/JS resources though - we set up Spring MVC to handle them.
     */
    @Bean Docket swagger() {
        return new Docket(DocumentationType.SWAGGER_2)
                .select()
                .apis(RequestHandlerSelectors.any())
                .paths(ant("/api/**"))
                .build();
    }
}

Spring MVC context (XML)

And finally we want to import that SwaggerConfig and handle Swagger UI (the HTML/CSS/JS files):

<!-- Swagger keeps HTML/CSS/JS resources in its jar file in META-INF folder. swagger-ui/ is the default context
     path where Swagger API resides. -->
<mvc:resources mapping="/swagger-ui/**" location="classpath:/META-INF/resources/webjars/springfox-swagger-ui/"/>
<context:component-scan base-package="io.elsci.moleve.web" />