将Url子域重定向到子目录

I am trying to redirect url. When someone type xyz.example.com then its redirected to example.com/zyz. I have No sub-domain. I am trying when someone enters exact string xyz.example.com then redirect to example.com/xyz. I am working on multi networking site.

xyz.example.com

This is not existing Domain .

example.com/xyz 

This is multi-networking site url no sub-domain existing for this

You will have to configure an apache virtual host.

<VirtualHost *:80>
    DocumentRoot "/www/subdomainFolder"
    ServerName subdomain.example.com

    # Other directives here
</VirtualHost>

In the other hand if you have a wildcard * IN A 192.0.2.1 to map all subdomains to your primary domain ip. You may:

<?php
   $hotsname = $_SERVER["HTTP_HOST"];
   $arr = explode('.',$hostname);
   $url='http://example.com/';
   if(count($arr)>2){
      // we have a subdomain

      // redirect xyz only.
      if($arr[0] == "xyz"){
          header("location:" $url. $arr[0]);
          exit();
      }
   }

   // Continue normal operation, no redirect.

?>

Apache VirtualHost Documentation