Using Apache Hive as a MapReduce Input Format and/or Scraping Hive Metadata

Our environment is heavy into storing data in hive. I find myself currently working on something that it outside the scope though. I have a mapreduce written, but it requires a lot of direct user inputs for information that could easily be scraped from Hive. That said, when I query hive for extended table data, all of the extended information is thrown out in 1 or 2 columns as a giant blob of almost-JSON. Is there either a convenient way to parse this information, or better yet, get it directly in a more direct manor?

Alternatively, if I could get pointed to documentation on manually using the CombinedHiveInputFormat, that would simplify my code a lot more. But it seems like that InputFormat is solely used inside of Hive, using it's custom structs.

Ultimately, what I want is to know table names, columns (not including partitions), and partition locations for the split a mapper is working on. If there is yet another way to accomplish this, I am eager to know.

Thanks! John