Changing a file's format in Android

I'm developing an Android miBook 开发者_如何学运维app in which when I go to a particular URL to download a book, it will show a book in .epub format.

I want to convert that .epub format to .zip, and after that, unzip the .zip file.

@vnshetty: Renaming a file and converting the format are not the same thing. I'm not sure what format 'epub' is but unless it really is a renamed zip file (which is a very specific compressed binary format) then that just won't work.

@Jack: You need to either find a reader library for 'epub' format files. If this wikipedia page is accurate, 'epub' is an XML format http://en.wikipedia.org/wiki/EPUB which should be straight forward to read using any of several XML parsing libraries.

May I ask why you then want to convert it to '.zip' format?

if you really want to compress the epub file you can write java code to zip the the content. but why you are doing like that zipping and unzipping? can you give some explanation?