Storing the document as a BLOB will be good if you need to extract the document, but it will be stored in its binary form. That means you can't search on it.
You should probably use Apache POI, JExcelAPI (a.k.a. jxl) or another library to read the document, then store its readable content in another field (type CLOB probably - a form of text-based BLOB; "text" is another often used name for it) on which you will then search.
Also depending on size files you are storing, it is not advisable to store large files in the base for performance reasons.
Instead saving the files on the hard disk and storing the path of the saved file in the database could be another solution.