Are you asking about browsing the client file system or the server file system? The client file system is not accessible by web pages (except for form file uploads, but I don't think that's what you're asking about). For the server file system you'd need to program it or use a 3rd-party library - there is no ready-made solution in JSP or servlets.
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com