To my knowledge the only documented, supported method for batch import is .doc / .docx, and as I noted before that has some serious bugs that would require a lot of cleanup.
There's a command-line interface that should work for batch import, but I encountered what seemed to be bugs: https://bobswift.atlassian.net/wiki/display/CSOAP/Confluence+Command+Line+Interface This page suggests that you could do it with WebDAV: https://confluence.atlassian.com/display/DOC/Importing+Content+Into+Confluence There are also SOAP and XML-RPC interfaces: https://developer.atlassian.com/display/CONFDEV/Confluence+XML-RPC+and+SOAP+APIs ePublisher uses XML-RPC for its wiki markup export: http://www.webworks.com/Documentation/Reverb/index.html#page/01.Welcome%2520to%2520ePublisher/Planning%2520and%2520Installing.5.23.htm
