How to access static resources when mapping a global front controller servlet on

Question

I ve mapped the Spring MVC dispatcher as a global front controller servlet on       lt servlet gt            lt servlet-name gt home lt  servlet-name gt              lt servlet-class gt org springframework web servlet DispatcherServlet lt  servlet-class gt        lt  servlet gt     lt servlet-mapping gt            lt servlet-name gt home lt  servlet-name gt              lt url-pattern gt    lt  url-pattern gt        lt  servlet-mapping gt    However  this mapping stops the access to static files like CSS  JS  images etc which are all in the  res  folder   How can I access them anyway

User · Answer

Map the controller servlet on a more specific url-pattern like /pages/*, put the static content in a specific folder like /static and create a Filter listening on /* which transparently continues the chain for any static content and dispatches requests to the controller servlet for other content.

In a nutshell:

<filter>
    <filter-name>filter</filter-name>
    <filter-class>com.example.Filter</filter-class>
</filter>
<filter-mapping>
    <filter-name>filter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

<servlet>
    <servlet-name>controller</servlet-name>
    <servlet-class>com.example.Controller</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>controller</servlet-name>
    <url-pattern>/pages/*</url-pattern>
</servlet-mapping>

with the following in filter's doFilter():

HttpServletRequest req = (HttpServletRequest) request;
String path = req.getRequestURI().substring(req.getContextPath().length());

if (path.startsWith("/static")) {
    chain.doFilter(request, response); // Goes to default servlet.
} else {
    request.getRequestDispatcher("/pages" + path).forward(request, response);
}

No, this does not end up with /pages in browser address bar. It's fully transparent. You can if necessary make "/static" and/or "/pages" an init-param of the filter.

User · Answer

If you use Tomcat  you can map resources to the default servlet    lt servlet-mapping gt       lt servlet-name gt default lt  servlet-name gt       lt url-pattern gt  static   lt  url-pattern gt   lt  servlet-mapping gt    and access your resources with url http    context path  static res      Also works with Jetty  not sure about other servlet containers

User · Answer

What you do is add a welcome file in your web xml   lt welcome-file-list gt       lt welcome-file gt index html lt  welcome-file gt   lt  welcome-file-list gt    And then add this to your servlet mappings so that when someone goes to the root of your application  they get sent to index html internally and then the mapping will internally send them to the servlet you map it to   lt servlet-mapping gt       lt servlet-name gt MainActions lt  servlet-name gt       lt url-pattern gt  main lt  url-pattern gt   lt  servlet-mapping gt   lt servlet-mapping gt       lt servlet-name gt MainActions lt  servlet-name gt       lt url-pattern gt  index html lt  url-pattern gt   lt  servlet-mapping gt    End result  You visit  Application  but you are presented with  Application MainActions servlet without disrupting any other root requests   Get it  So your app still sits at a sub url  but automatically gets presented when the user goes to the root of your site  This allows you to have the  images bob img still go to the regular place  but     is your app

User · Answer

In Embedded Jetty I managed to achieve something similar by adding a mapping for the  css  directory in web xml  Explicitly telling it to use DefaultServlet    lt servlet gt     lt servlet-name gt DefaultServlet lt  servlet-name gt     lt servlet-class gt org eclipse jetty servlet DefaultServlet lt  servlet-class gt   lt  servlet gt    lt servlet-mapping gt     lt servlet-name gt DefaultServlet lt  servlet-name gt     lt url-pattern gt  css   lt  url-pattern gt   lt  servlet-mapping gt

User · Answer

With regard to Tomcat  a lot depends on the particular version  There was a bug fix https   bz apache org bugzilla show bug cgi id 50026 which means the servlet-mapping  other than for      for the default servlet behaves differently in Tomcat 6 0 29  and earlier  compared with later versions

User · Answer

The best way to handle this is using some kind of URL re-writing   In this way  you can have clean restful URLs  and NOT with any extensions i e abc com welcom register as opposed to abc com welcome resister html  I use Tuckey URL which is pretty cool   It s got instructions on how to set up your web app I have set it up with my Spring MVC web app  Of course  everything was fine until I wanted to use annotations for Spring 3 validations like  Email or  Null for domain objects     When I add the Spring mvc directives    lt  mvc annotation-driven    gt    lt  mvc default-servlet-handler   gt       it breaks the good ol Tuckey code  Apparently   lt  mvc default-servlet-handler   gt  replaces Tuckey  which I m still trying to solve

User · Answer

Static  files in App Engine aren t directly accessible by your app  You either need to upload them twice  or serve the static files yourself  rather than using a static handler

User · Answer

lt  xml version  1 0  encoding  UTF-8   gt   lt beans xmlns  http   www springframework org schema beans      xmlns mvc  http   www springframework org schema mvc      xmlns xsi  http   www w3 org 2001 XMLSchema-instance      xsi schemaLocation           http   www springframework org schema beans         http   www springframework org schema beans spring-beans-3 0 xsd         http   www springframework org schema mvc         http   www springframework org schema mvc spring-mvc-3 0 xsd  gt   lt mvc default-servlet-handler  gt   lt  beans gt    and if you want to use annotation based configuration use below code   Override     public void configureDefaultServletHandling DefaultServletHandlerConfigurer configurer            configurer enable

User · Answer

Add the folders which you don t want to trigger servlet processing to the  lt static-files gt  section of your appengine-web xml file   I just did this and looks like things are starting to work ok   Here s my structure       pages  lt  jsp files    css  I added   pages     and   css     to the  lt static-files gt  section and I can now forward to a  jsp file from inside a servlet doGet without causing an infinite loop

User · Answer

With Spring 3 0 4 RELEASE and higher you can use   lt mvc resources mapping   resources     location   public-resources    gt    As seen in Spring Reference

User · Answer

After trying the filter approach without success  it did for some reason not enter the doFilter   function  I changed my setup a bit and found a very simple solution for the root serving problem   Instead of serving         in my main Servlet  I now only listen to dedicated language prefixes  EN    EN       DE    DE      Static content gets served by the default Servlet and the empty root requests go to the index jsp which calls up my main Servlet with the default language       lt  jsp include page   EN         no other content on the index page

User · Answer

I ve run into this also and never found a great solution   I ended up mapping my servlet one level higher in the URL hierarchy    lt servlet-mapping gt            lt servlet-name gt home lt  servlet-name gt                  lt url-pattern gt  app   lt  url-pattern gt        lt  servlet-mapping gt    And now everything at the base context  and in your  res directory  can be served up by your container

User · Answer

The reason for the collision seems to be because  by default  the context root       is to be handled by org apache catalina servlets DefaultServlet  This servlet is intended to handle requests for static resources   If you decide to bump it out of the way with your own servlet  with the intent of handling dynamic requests  that top-level servlet must also carry out any tasks accomplished by catalina s original  DefaultServlet  handler   If you read through the tomcat docs  they make mention that True Apache  httpd  is better than Apache Tomcat for handling static content  since it is purpose built to do just that  My guess is because Tomcat by default uses org apache catalina servlets DefaultServlet to handle static requests  Since it s all wrapped up in a JVM  and Tomcat is intended to as a Servlet JSP container  they probably didn t write that class as a super-optimized static content handler  It s there  It gets the job done  Good enough    But that s the thing that handles static content and it lives at      So if you put anything else there  and that thing doesn t handle static requests  WHOOPS  there goes your static resources    I ve been searching high and low for the same answer and the answer I m getting everywhere is  if you don t want it to do that  don t do that    So long story short  your configuration is displacing the default static resource handler with something that isn t a static resource handler at all  You ll need to try a different configuration to get the results you re looking for  as will I

User · Answer

I d recommend trying to use a Filter instead of a default servlet whenever possible   Other two possibilities   Write a FileServlet yourself  You ll find plenty examples  it should just open the file by URL and write its contents into output stream  Then  use it to serve static file request   Instantiate a FileServlet class used by Google App Engine and call service request  response  on that FileServlet when you need to serve the static file at a given URL   You can map  res   to YourFileServlet or whatever to exclude it from DispatcherServlets  handling  or call it directly from DispatcherServlet   And  I have to ask  what does Spring documentation say about this collision  I ve never used it

User · Answer

I found that using    lt mvc default-servlet-handler   gt    in the spring MVC servlet bean definition file works for me  It passes any request that isn t handled by a registered MVC controller on to the container s original default handler  which should serve it as static content   Just make sure you have no controller registered that handles everything  and it should work just fine   Not sure why  logixplayer suggests URL rewriting  you can achieve the effect he s looking for just adequately using Spring MVC alone

User · Answer

In section  quot 12 2 Specification of Mappings quot  of the Servlet Specification  it says   A string containing only the         character indicates the  quot default quot  servlet of the application   So in theory  you could make your Servlet mapped to    do  getServletContext   getNamedDispatcher  quot   quot   forward req res        if you didn t want to handle it yourself  However  in practice  it doesn t work  In both Tomcat and Jetty  the call to getServletContext   getNamedDispatcher      returns null if there is a servlet mapped to

User · Answer

I found a simpler solution with a dummy index file   Create a Servlet  or use the one you wanted to respond to      which maps to   index html   Solutions mentioned here use the mapping via XML  I used the 3 0 version with annotation  WebServlet  Then create a static  empty  file at the root of the static content named  index html   I was using Jetty  and what happened was that the server recognized the file instead of listing the directory but when asked for the resource  my Servlet took control instead  All other static content remained unaffected

User · Answer

Serving static content with appropriate suffix in multiple servlet-mapping definitions solved the security issue which is mentioned in one of the comments in one of the answers posted  Quoted below      This was a security hole in Tomcat  WEB-INF and META-INF contents are accessible this way  and it has been fixed in 7 0 4  and will be ported to 5 x and 6 x as well       BalusC Nov 2  10 at 22 44   which helped me a lot  And here is how I solved it    lt servlet-mapping gt       lt servlet-name gt default lt  servlet-name gt       lt url-pattern gt   js lt  url-pattern gt   lt  servlet-mapping gt   lt servlet-mapping gt       lt servlet-name gt default lt  servlet-name gt       lt url-pattern gt   css lt  url-pattern gt   lt  servlet-mapping gt   lt servlet-mapping gt       lt servlet-name gt default lt  servlet-name gt       lt url-pattern gt   jpg lt  url-pattern gt   lt  servlet-mapping gt   lt servlet-mapping gt       lt servlet-name gt default lt  servlet-name gt       lt url-pattern gt   htm lt  url-pattern gt   lt  servlet-mapping gt   lt servlet-mapping gt       lt servlet-name gt default lt  servlet-name gt       lt url-pattern gt   html lt  url-pattern gt   lt  servlet-mapping gt

User · Answer

As of 3 0 4 you should be able to use mvc resources in combination with mvc default-servlet-handler as described in the spring documentation to achieve this   http   static springsource org spring docs 3 0 x spring-framework-reference html mvc html mvc-static-resources

[java] How to access static resources when mapping a global front controller servlet on /*

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