Querying a Lucene index file

I'm trying to query a Lucene index file through QueryParser. However I would like to see the format of the index file before querying it. Is there a way to lookup the stru开发者_开发技巧cture of a Lucene index file, sort of like how I'm able to lookup the structure of a regular SQL table?

The reason is that I haven't built this index file myself and would like to get my way around it before querying it.

You can use Luke, or programmatically IndexReader.getFieldNames().

Luke - Lucene Index Toolbox

Luke is a handy development and diagnostic tool, which accesses already existing Lucene indexes and allows you to display and modify their content in several ways