https://www.v2ex.com/t/439020

nginx.conf

worker_processes  1;
error_log  logs/error.log;
pid        logs/nginx.pid;
worker_rlimit_nofile 8192;

events {
  worker_connections  4096;  ## Default: 1024
}

http {
  index    index.html index.htm index.php;

  default_type application/octet-stream;
  log_format   main '$remote_addr - $remote_user [$time_local]  $status '
    '"$request" $body_bytes_sent "$http_referer" '
    '"$http_user_agent" "$http_x_forwarded_for"';
  access_log   logs/access.log  main;
  sendfile     on;
  tcp_nopush   on;

  server {
    listen       80;
    access_log   logs/80.access.log  main;
    root         html;

    location ~ /aaa/(.*) {
      proxy_pass http://127.0.0.1:81/$1;
    }

    location ~ /bbb/(.*) {
      proxy_pass http://127.0.0.1:82/$1;
    }

    location ~ /ccc/(.*) {
      proxy_pass http://127.0.0.1:83/$1;
    }
  }

  server {
    listen       81;
    access_log   logs/81.access.log  main;
    root         static_a;
  }

  server {
    listen       82;
    access_log   logs/82.access.log  main;
    root         static_b;
  }

  server {
    listen          83;
    access_log      logs/83.access.log main;
    root            static_c;
  }
}

mkdir static_a static_b static_c
echo a > static_a/a.txt
echo b > static_b/b.txt
echo c > static_c/c.txt

curl http://127.0.0.1:80/aaa/a.txt
curl http://127.0.0.1:80/bbb/b.txt
curl http://127.0.0.1:80/ccc/c.txt