I'm not clear on the scenario you wish to address. Since you have a resultMap, you apparently know the output of the query that fills it. By that, I mean you are not running a completely dynamic query. So, if you have a static query, why not just create the temporary table directly from that? Most DBMSs have the capability to create temporary tables directly in SQL. That seems like a more direct approach than first running the original query, converting that to a Java class via an XML resultMap, then sending that Java class *back* to the database and trying to convert it to a temporary table. Perhaps explain your scenario a bit more.
If you're attempting to dynamically introspect a Java class in order to dynamically create a SQL table from it, MyBatis doesn't have the ability to do that. I suppose you could do that completely in Java and send a dynamic SQL statement to MyBatis to execute.