如何实现网站的二级域名设置,如:淘宝店二级域名?

worker_processes  8;#cpu总线程数
error_log  logs/error.log;
events {
    worker_connections  1024;
}
http {
    include       mime.types;
    default_type  application/octet-stream;
    sendfile        on;
    keepalive_timeout  65;
    gzip  on;
    upstream  19810109.org   {
       #ip_hash;
              server   19810109.org:8080 weight=1;#tomcat0 port is 8080 权重 1
              server   19810109.org:8081 weight=1;#tomcat1 port is 8081 权重 1
    }
    server {
        listen       80;
        server_name  *.19810109.org;#开启泛域名解析
        charset utf-8;
         if ($host ~* (.*)\.19810109\.org) {#将头地址存入变量variable
                  set $variable $1;
         }
         if ($variable = "") {#如果variable为空则跳转到www.19810109.org
                  rewrite .* http://www.19810109.org permanent;
         }
         if ($variable !~* "^www$") {#如果variable不为空且不为www则跳转到http://variable.19810109.org/test.jsp?id=variable
                 rewrite .* /test.jsp?id=$variable last;
         }
        location / {
            root   html;
            index  index.html index.htm;
            proxy_pass        http://19810109.org;
            proxy_set_header  X-Real-IP  $remote_addr;
            client_max_body_size  100m;
 }
        location ~ ^/(WEB-INF)/ { 
     deny all; 
        }
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }
}