I have a regular old PDF file on my desktop, and that same PDF file is attached to a record in Salesforce.  Now, when I change the PDF's extension on my computer to ".txt", I can then open it and read the texttual data that makes up the file.  I need to extract some data at the beginning of the ".txt" version of the file that details how many pages the PDF consists of, but I need to do this for many PDF files that are already in Salesforce.

I discovered the "String pdf = System.EncodingUtil.base64Encode(a.Body)" method, which apparently converts the base64 blob representation of the file into an unencoded string... but when I looked at the actual output, I realized that it was totally different compared to the ".txt" version of the PDF on my desktop.  It seems that I'm not encoding/decoding the attachment Body blob to the correct format, but I'm totally clueless as to what to convert it to, or what method I would need to use to convert it.

Does anyone have any ideas as to how I would convert the PDF data to whatever format it gets converted to when I just change the extension on my computer and view it in notepad?

Thanks!