How can I serve static content with spring boot that's external to my jar?
<p>I have the following from a docker container build/start</p>

<pre><code>Step 13 : ENV WEBROOT /package/dist
 ---&gt; Running in 0d0d3651fa08
 ---&gt; e80c20af18ba
Removing intermediate container 0d0d3651fa08
Step 14 : USER $SPRING_APPLICATION_NAME
 ---&gt; Running in 7fe20b631fee
 ---&gt; 37435f78675b
Removing intermediate container 7fe20b631fee
Step 15 : CMD ls -l $WEBROOT &amp;&amp; java -Djava.security.egd=file:/dev/urandom -Dlogging.level.org.springframework=DEBUG -Dspring.resources.static-locations=file:$WEBROOT/** -jar $JAR
 ---&gt; Running in 9b71fb7bde61
 ---&gt; 82e77cfde02a
Removing intermediate container 9b71fb7bde61
Successfully built 82e77cfde02a
total 1788
-rw-r--r--    1 root     root        152796 Aug 13 06:46 1dc35d25e61d819a9c357074014867ab.ttf
-rw-r--r--    1 root     root         76518 Aug 13 06:46 25a32416abee198dd821b0b17a198a8f.eot
-rw-r--r--    1 root     root         18028 Aug 13 06:46 448c34a56d699c29117adc64c43affeb.woff2
-rw-r--r--    1 root     root        108738 Aug 13 06:46 89889688147bd7575d6327160d64e760.svg
-rw-r--r--    1 root     root        170605 Aug 13 06:46 app.ff81c2c4df5a052cee7f.bundle.js
-rw-r--r--    1 root     root            87 Aug 13 06:46 app.ff81c2c4df5a052cee7f.bundle.map
-rw-r--r--    1 root     root        129946 Aug 13 06:46 aurelia-bootstrap.920ea8ba3d3ae900df6b.bundle.js
-rw-r--r--    1 root     root        307763 Aug 13 06:46 aurelia.042f8d07b45053bfe6a6.bundle.js
-rw-r--r--    1 root     root         90412 Aug 13 06:46 c8ddf1e5e5bf3682bc7bebf30f394148.woff
-rw-r--r--    1 root     root        391622 Aug 13 06:46 d7c639084f684d66a1bc66855d193ed8.svg
-rw-r--r--    1 root     root         45404 Aug 13 06:46 e18bbf611f2a2e43afc071aa2f4e1512.ttf
-rw-r--r--    1 root     root         71896 Aug 13 06:46 e6cf7c6ec7c2d6f670ae9d762604cb0b.woff2
-rw-r--r--    1 root     root         20127 Aug 13 06:46 f4769f9bdb7466be65088239c12046d1.eot
-rw-r--r--    1 root     root         23424 Aug 13 06:46 fa2772327f55d8198301fdb8bcfc8158.woff
-rw-r--r--    1 root     root          2249 Aug 13 06:46 favicon.ico
-rw-r--r--    1 root     root           568 Aug 13 06:46 index.html
-rw-r--r--    1 root     root        183950 Aug 13 06:46 styles.css
</code></pre>

<p>container starts fine and all that, get to the end of the very long debug logging</p>

<pre><code>2016-08-13 08:09:17.006 DEBUG 8 --- [           main] o.s.w.s.resource.ResourceUrlProvider     : Found resource handler mapping: URL pattern="/**/favicon.ico", locations=[URL [file:/package/dist/**], class path resource []], resolvers=[org.springframework.web.servlet.resource.PathResourceResolver@25df00a0]
2016-08-13 08:09:17.006 DEBUG 8 --- [           main] o.s.w.s.resource.ResourceUrlProvider     : Found resource handler mapping: URL pattern="/webjars/**", locations=[class path resource [META-INF/resources/webjars/]], resolvers=[org.springframework.web.servlet.resource.PathResourceResolver@4d15107f]
2016-08-13 08:09:17.006 DEBUG 8 --- [           main] o.s.w.s.resource.ResourceUrlProvider     : Found resource handler mapping: URL pattern="/**", locations=[URL [file:/package/dist/**]], resolvers=[org.springframework.web.servlet.resource.PathResourceResolver@7b4c50bc]
</code></pre>

<p>so it looks like it's recognizing the path, and we know there's stuff in there because I listed it. I hit localhost:8080 (which is the right server)</p>

<pre><code>2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.b.w.f.OrderedRequestContextFilter    : Bound request context to thread: org.springframework.session.web.http.SessionRepositoryFilter$SessionRepositoryRequestWrapper@4a8af076
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.web.util.matcher.OrRequestMatcher  : Trying to match using Ant [pattern='/css/**']
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.w.u.matcher.AntPathRequestMatcher  : Checking match of request : '/'; against '/css/**'
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.web.util.matcher.OrRequestMatcher  : Trying to match using Ant [pattern='/js/**']
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.w.u.matcher.AntPathRequestMatcher  : Checking match of request : '/'; against '/js/**'
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.web.util.matcher.OrRequestMatcher  : Trying to match using Ant [pattern='/images/**']
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.w.u.matcher.AntPathRequestMatcher  : Checking match of request : '/'; against '/images/**'
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.web.util.matcher.OrRequestMatcher  : Trying to match using Ant [pattern='/webjars/**']
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.w.u.matcher.AntPathRequestMatcher  : Checking match of request : '/'; against '/webjars/**'
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.web.util.matcher.OrRequestMatcher  : Trying to match using Ant [pattern='/**/favicon.ico']
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.w.u.matcher.AntPathRequestMatcher  : Checking match of request : '/'; against '/**/favicon.ico'
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.web.util.matcher.OrRequestMatcher  : Trying to match using Ant [pattern='/error']
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.w.u.matcher.AntPathRequestMatcher  : Checking match of request : '/'; against '/error'
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.web.util.matcher.OrRequestMatcher  : No matches found
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.s.w.u.matcher.AntPathRequestMatcher  : Checking match of request : '/'; against '/'
2016-08-13 08:15:16.448 DEBUG 8 --- [nio-8080-exec-2] o.s.security.web.FilterChainProxy        : / has an empty filter list
2016-08-13 08:15:16.449 DEBUG 8 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet        : DispatcherServlet with name 'dispatcherServlet' processing GET request for [/]
2016-08-13 08:15:16.450 DEBUG 8 --- [nio-8080-exec-2] o.s.b.a.e.mvc.EndpointHandlerMapping     : Looking up handler method for path /
2016-08-13 08:15:16.453 DEBUG 8 --- [nio-8080-exec-2] o.s.b.a.e.mvc.EndpointHandlerMapping     : Did not find handler method for [/]
2016-08-13 08:15:16.453 DEBUG 8 --- [nio-8080-exec-2] s.w.s.m.m.a.RequestMappingHandlerMapping : Looking up handler method for path /
2016-08-13 08:15:16.454 DEBUG 8 --- [nio-8080-exec-2] s.w.s.m.m.a.RequestMappingHandlerMapping : Did not find handler method for [/]
2016-08-13 08:15:16.454 DEBUG 8 --- [nio-8080-exec-2] o.s.w.s.handler.SimpleUrlHandlerMapping  : Matching patterns for request [/] are [/**]
2016-08-13 08:15:16.454 DEBUG 8 --- [nio-8080-exec-2] o.s.w.s.handler.SimpleUrlHandlerMapping  : URI Template variables for request [/] are {}
2016-08-13 08:15:16.454 DEBUG 8 --- [nio-8080-exec-2] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapping [/] to HandlerExecutionChain with handler [ResourceHttpRequestHandler [locations=[URL [file:/package/dist/**]], resolvers=[org.springframework.web.servlet.resource.PathResourceResolver@7b4c50bc]]] and 1 interceptor
2016-08-13 08:15:16.454 DEBUG 8 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet        : Last-Modified value for [/] is: -1
2016-08-13 08:15:16.454 DEBUG 8 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet        : Null ModelAndView returned to DispatcherServlet with name 'dispatcherServlet': assuming HandlerAdapter completed request handling
2016-08-13 08:15:16.454 DEBUG 8 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet        : Successfully completed request
2016-08-13 08:15:16.454 DEBUG 8 --- [nio-8080-exec-2] o.s.b.w.f.OrderedRequestContextFilter    : Cleared thread-bound request context: org.springframework.session.web.http.SessionRepositoryFilter$SessionRepositoryRequestWrapper@4a8af076
2016-08-13 08:15:16.455 DEBUG 8 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet        : DispatcherServlet with name 'dispatcherServlet' processing GET request for [/error]
2016-08-13 08:15:16.455 DEBUG 8 --- [nio-8080-exec-2] o.s.b.a.e.mvc.EndpointHandlerMapping     : Looking up handler method for path /error
2016-08-13 08:15:16.456 DEBUG 8 --- [nio-8080-exec-2] o.s.b.a.e.mvc.EndpointHandlerMapping     : Did not find handler method for [/error]
2016-08-13 08:15:16.456 DEBUG 8 --- [nio-8080-exec-2] s.w.s.m.m.a.RequestMappingHandlerMapping : Looking up handler method for path /error
2016-08-13 08:15:16.456 DEBUG 8 --- [nio-8080-exec-2] s.w.s.m.m.a.RequestMappingHandlerMapping : Returning handler method [public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)]
2016-08-13 08:15:16.456 DEBUG 8 --- [nio-8080-exec-2] o.s.b.f.s.DefaultListableBeanFactory     : Returning cached instance of singleton bean 'basicErrorController'
2016-08-13 08:15:16.456 DEBUG 8 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet        : Last-Modified value for [/error] is: -1
2016-08-13 08:15:16.457 DEBUG 8 --- [nio-8080-exec-2] o.s.w.s.v.ContentNegotiatingViewResolver : Requested media types are [text/html, text/html;q=0.8] based on Accept header types and producible media types [text/html])
2016-08-13 08:15:16.457 DEBUG 8 --- [nio-8080-exec-2] o.s.b.f.s.DefaultListableBeanFactory     : Returning cached instance of singleton bean 'error'
2016-08-13 08:15:16.457 DEBUG 8 --- [nio-8080-exec-2] o.s.w.servlet.view.BeanNameViewResolver  : No matching bean found for view name 'error.html'
2016-08-13 08:15:16.457 DEBUG 8 --- [nio-8080-exec-2] o.s.w.s.v.ContentNegotiatingViewResolver : Returning [org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$SpelView@316bcf94] based on requested media type 'text/html'
2016-08-13 08:15:16.457 DEBUG 8 --- [nio-8080-exec-2] o.s.web.servlet.DispatcherServlet        : Rendering view [org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$SpelView@316bcf94] in DispatcherServlet with name 'dispatcherServlet'
2016-08-13 08:15:16.457 DEBUG 8 --- [nio-8080-exec-2] 
o.s.web.servlet.DispatcherServlet        : Successfully completed request
</code></pre>

<p>confused, why don't I see the index.html that's living in /package/dist when requesting /? I get a 404 instead.</p>

<p>Spring Boot (1.4.0) version packaged with IO Platform Athens RC1</p>

<p>How can I serve my static content that is external to the jar?</p>