Apache + Tomcat: Using mod_proxy instead of AJP

The settings you are looking for are:

<VirtualHost *:80>
  ServerName public.server.name

  ProxyRequests Off
  ProxyPreserveHost On

  <Proxy *>
    Order deny,allow
    Allow from all
  </Proxy>

  ProxyPass / http://localhost:8080/
  ProxyPassReverse / http://localhost:8080/
</VirtualHost>

Note that we're using localhost as the proxy target. We can do this since we enable ProxyPreserveHost. The documentation states that

It is mostly useful in special configurations like proxied mass name-based virtual hosting, where the original Host header needs to be evaluated by the backend server.

which sounds exactly like what you are doing.

I think your best bet if you want multiple sites on the same server is to use virtual hosts in your Apache configuration. Here's an example:

<VirtualHost *:80>
ServerName server.domain.com

ProxyRequests Off
<Proxy *>
    Order deny,allow
    Allow from all
</Proxy>

ProxyPass / http://server.domain.com:8080/
ProxyPassReverse / http://server.domain.com:8080/
<Location />
    Order allow,deny
    Allow from all
</Location>

As long as you have server.domain.com registered in your external DNS, the incoming host name will be displayed in client URLs. I'm running a single server hosting 6 separate sites, including 3 that are back by Tomcat, using this method.