How to serve all existing static files directly with NGINX, but proxy other requests to jetty?

[AlexLuya]

My question is similar to
http://stackoverflow.com/questions/869001/how-to-serve-all-existing-static-files-directly-with-nginx-but-proxy-to-apache,different
is that my site directory structure looks like this:

/nginxRoot/test/js        
/nginxRoot/test/images  
/nginxRoot/test/html
........       

So the site root isn't "/nginxRoot/" but "/nginxRoot/test/"

I want to nginx to serve all static files that have been put at
directories:js,images,html,and proxy other requests to jetty,I have tried:

location ~ ^/test/(.*)\.  
(jpg|jpeg|gif|png|js|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf|html|htm)$
{
    root  /ngixRoot/test;
}

 location ~ ^/test/(.*)$ {
    proxy_pass http://127.0.0.1:8080/$1$is_args$args;
    proxy_redirect off;
}

All requests to jetty works,but all requests to static files don't,I doubt
they are forwarded to jetty also,is that true?how to fix this problem?

After a squence of Q&A,I was told that "try_files" is  another option(not
sure which one is more propriate for my use case ),then after googling and
reading,I tried this:

location ~ ^/test/$ {       
   try_files $uri $uri/ @jetty
} 

location @jetty {
    internal;
    add_header X-Local true;
    add_header X-Cache $upstream_cache_status;

    proxy_pass              http://$http_host:8080$uri$is_args$args;
    proxy_cache_key         backend$request_uri;
    proxy_cache_valid       200  1h;
    proxy_cache_use_stale   error timeout invalid_header;
}

but get "403 forbidden" error,so please tell me what I did wrong?Thanks.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,254884,254884#msg-254884