Spring boot & Swagger 2 UI & custom requestmappinghandlermapping - mapping issue

Question

I have own RequestMappingHandlerMapping and I am using springfox-swagger-ui. After adding my custom mapping, I am not able to achieve swagger ui at http://localhost:8080/swagger-ui.html. Any ideas?

This is my configuration.

    @Configuration
       public class WebMvcConfig extends WebMvcConfigurationSupport {
    @Override
    @Bean
    public RequestMappingHandlerMapping requestMappingHandlerMapping() {
        return new ApiVersionRequestMappingHandlerMapping("v");
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry
          .addResourceHandler("/webjars/**")
          .addResourceLocations("(META-INF/resources/webjars");
    }
}

Here's my pom.xml:

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.hateoas</groupId>
        <artifactId>spring-hateoas</artifactId>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger-ui</artifactId>
        <version>2.4.0</version>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
        <version>2.4.0</version>
    </dependency>
    <dependency>
        <groupId>javax.inject</groupId>
        <artifactId>javax.inject</artifactId>
        <version>1</version>
    </dependency>

Answer 1

When you override WebMvcConfigurationSupport, you are also overriding spring Boot's mvc auto configuration (WebMvcAutoConfiguration). Therefore, resources that need spring boot's configuration will not work. This is not a problem specific to swagger.

You can find more info about this here:

https://github.com/spring-projects/spring-boot/issues/5004

As the github issue suggests, there will be changes on this in the future to make it easier. Currently there are some workarounds, as suggested there.

A quick and dirty way of doing this is by copying and pasting the WebMvcAutoConfiguration class into your own class, returning your own HandlerMapping from the requestMappingHandlerMapping() method of EnableWebMvcConfiguration and registering the copy of the WebMvcAutoConfiguration as an auto configuration class. You can see instructions here:

http://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-developing-auto-configuration.html

Make sure you place your copy of the WebMvcAutoConfiguration at some package which is not component scanned and picked up automatically. It should just be registered as explained in the above link.

Also make sure you set the order of you custom HandlerMapping to 0 before returning it from the requestMappingHandlerMapping() method, like so:

@Bean
@Primary
@Override
public RequestMappingHandlerMapping requestMappingHandlerMapping() {
    // Must be @Primary for MvcUriComponentsBuilder to work

    ApiVersionRequestMappingHandlerMapping handlerMapping = new ApiVersionRequestMappingHandlerMapping("v");
    handlerMapping.setOrder(0);
    handlerMapping.setInterceptors(getInterceptors());
    handlerMapping.setContentNegotiationManager(mvcContentNegotiationManager());

    PathMatchConfigurer configurer = getPathMatchConfigurer();
    if (configurer.isUseSuffixPatternMatch() != null) {
        handlerMapping.setUseSuffixPatternMatch(configurer.isUseSuffixPatternMatch());
    }
    if (configurer.isUseRegisteredSuffixPatternMatch() != null) {
        handlerMapping.setUseRegisteredSuffixPatternMatch(configurer.isUseRegisteredSuffixPatternMatch());
    }
    if (configurer.isUseTrailingSlashMatch() != null) {
        handlerMapping.setUseTrailingSlashMatch(configurer.isUseTrailingSlashMatch());
    }
    if (configurer.getPathMatcher() != null) {
        handlerMapping.setPathMatcher(configurer.getPathMatcher());
    }
    if (configurer.getUrlPathHelper() != null) {
        handlerMapping.setUrlPathHelper(configurer.getUrlPathHelper());
    }

    return handlerMapping;
}