Spring Swagger2 integration ServletContext autowiring issue

Question

I'm running Spring 4 mvc with embedded Jetty 9. I tried to plug in Swagger2 tool, but I faced next exception

Error creating bean with name 'documentationPluginsBootstrapper'

the root cause of this exception is

nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [javax.servlet.ServletContext] found for dependency [javax.servlet.ServletContext]: expected at least 1 bean which qualifies as autowire candidate for this dependency.

This is my SwaggerConfigClass

@Configuration
@EnableSwagger2
public class SwaggerConfig {
    private static final Logger logger = Logger.getLogger(SwaggerConfig.class);

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

    private ApiInfo apiInfo() {
        return new ApiInfoBuilder()
                .title("TITLE")
                .description("DESCRIPTION")
                .version("VERSION")
                .termsOfServiceUrl("http://terms-of-services.url")
                .license("LICENSE")
                .licenseUrl("http://url-to-license.com")
                .build();
    }
}

After that I created factory class

public class ServletContextFactory implements FactoryBean<ServletContext>,
        ServletContextAware {
    private ServletContext servletContext;

   @Override
    public ServletContext getObject() throws Exception {
        return servletContext;
    }

    @Override
    public Class<?> getObjectType() {
        return ServletContext.class;
    }

    @Override
    public boolean isSingleton() {
        return true;
    }

    @Override
    public void setServletContext(ServletContext servletContext) {
        this.servletContext = servletContext;
    }

}

and then manually used it in redeclared bean

@Bean
public DocumentationPluginsBootstrapper documentationPluginsBootstrapper(DocumentationPluginsManager documentationPluginsManager,  
                                                                         List<RequestHandlerProvider> handlerProviders,
                                                                         DocumentationCache scanned,
                                                                         ApiDocumentationScanner resourceListing,
                                                                         TypeResolver typeResolver,
                                                                         Defaults defaults) throws Exception {

    return new DocumentationPluginsBootstrapper(documentationPluginsManager,
            handlerProviders,
            scanned,
            resourceListing,
            typeResolver,
            defaults,
            new ServletContextFactory().getObject());
}

but still had an exception (another exception) NullPointerException as next

Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException

So can anyone suggest some solution of this autowiring problem?

Answer 1

So, the reason why Swagger did not start was refreshing WebContext of my application manually before jetty server start. As a result ServletContext Bean was not added into the WebContext at the time of Swagger initialization.

Answer 2

Here's your problem:

return new DocumentationPluginsBootstrapper(documentationPluginsManager,
    handlerProviders,
    scanned,
    resourceListing,
    typeResolver,
    defaults,
    new ServletContextFactory().getObject());

Spring is out of the picture the moment you call new to create your ServletContextFactory. It's your responsibility to inject the dependencies into ServletContextFactory.

This is a common mistake by new Spring users.