A Blob is a database concept and shouldn't come anywhere near a JSP page. The conversion of data types like clobs, blobs and SQL dates to "everyday" counterparts should be handled in the model code and never come near the presentation code.
If I were working on this, I would first focus on converting a binary stream or byte array into a string. Once I got that working in a small, standalone Java app, I would figure out how best to use that code in my webapp; servlet, helper bean, custom tag, etc.
Since the first task at hand is not JSP specific, I'm going to move this thread to the IO/Streams forum.