title: SpringFox Docket per controller not working in spring boot
body: <p>In my spring boot application, I have multiple Rest Controllers and need to generate swagger for each controller seperately.<br><br>
  By using below Docket config for each controller in my spring boot application class, i am able to download controller specific swagger by going to /v2/api-docs?group=ai where i = 1 to n<BR><br>
  However in swagger-ui.html, when i select a1(/v2/api-docs?group=a1), it shows path as "/api/a1/a1", while selecting a2(/v2/api-docs?greoup=a2), it shows correct path i.e. /api/a2<br><br>
  I have tried changing in Docket ,paths regex to absolute e.g.  "api/a1" etc but that didn't help.<br> </p>
  
  <pre><code>@Bean
  public Docket a1Api() {
      return new Docket(DocumentationType.SWAGGER_2)
      .groupName("a1")
      .apiInfo(a1Info())
      .select().apis(RequestHandlerSelectors.any())
      .paths(regex("/api/a1.*"))
      .build()
      .pathMapping("/");
  }
  
  @Bean
  public Docket a2Api() {
      return new Docket(DocumentationType.SWAGGER_2)
      .groupName("a2")
      .apiInfo(a1Info())
      .select().apis(RequestHandlerSelectors.any())
      .paths(regex("/api/a2.*"))
      .build()
      .pathMapping("/");
  }
  
  private ApiInfo a1Info() {
      return new ApiInfoBuilder()
      .title("a1 Swagger 2.0")
      .description("a1")
      .license("a1")
      .version("1.0")
      .build();
  }
  
  private ApiInfo a2Info() {
      return new ApiInfoBuilder()
      .title("a2 Swagger 2.0")
      .description("a2")
      .license("a2")
      .version("1.0")
      .build();
  }
  </code></pre>
  
  <p>Rest Controllers <br></p>
  
  <pre><code>@RestController
  @Api(tags = "A1")
  @RequestMapping("/api/a1")
  public class a1Controller {
  
          @ApiOperation(value = "a1")
          @RequestMapping(value = "", method = RequestMethod.POST)
          public a1Response invoke(@RequestBody a1Request va1Request) {
              .....;
          }
  }
  
  @RestController
  @Api(tags = "An")
  @RequestMapping("/api/an")
  public class a1Controller {
  
          @ApiOperation(value = "an")
          @RequestMapping(value = "", method = RequestMethod.POST)
          public anResponse invoke(@RequestBody anRequest vanRequest) {
              .....;
          }
  }
  </code></pre>
  
  <p>Any idea how can i address this....<br>
  i am using springfox swagger version 2.6.1</p>