Reading file on the server..

Question

I am reading a file from the database and I want to store it on the server side. I have created a directory "download". But how to pass the path of this folder to the outputstream. I am giving the path as "/rootfolder/downloads/somefile.txt" but i am getting an error..system cannot find the specified path..
fs=new FileOutputStream("/rootfolder/downloads/somefile.txt" );
This is not working..how to do this..

Answer 1

I don't know if you're still watching this thread, but here is some follow up on this:
As to when you need to use the virtual directory for
paths and when you need to use absolute paths and
getRealPath(), I'm not entirely sure. Maybe the rule
is: if you're dealing with servlets or jsp's, i.e.
things that get the request and response objects, you
use the virtual directory; and when you deal with
other files you use absolute paths?Methods that are servlet methods, i.e. methods that are part of the servlet API like getRequestDispatcher(), know about the "context root" of the application (=your application directory) and can resolve paths relative to the context root, which are paths that start with a "/". However, a regular java method like a FileOutputStream constructor in the following code:
s=new FileOutputStream("/rootfolder/downloads/somefile.txt" );has no idea what a context root is or what a servlet is. Rather, the constructor needs an absolute path to the location of the file. That's why your path that started with a "/" wouldn't work.
The "/"
isn't always required though, because sometimes you
can leave off the slash, and then the path will be
interpreted relative to the current directory in the
virtual directory structure.This part gets a little tricky, and the following has to do with the path used when you want to forward the request to another servlet using getRequestDispatcher().
a) If you use a ServletContext object to call getRequestDispatcher(path), then you must use a path that is relative to the context root and start's with a "/".
b) If you use the request object to call getRequestDispatcher(path), then you can use a path:
----1) relative to the context root that starts with a "/", or
----2) relative to the "current directory". The "current directory" is determined by the url in the request. To discover what url is in the request, you need to determine what url requested your servlet. You can do that by looking at the <servlet-mapping> in your web.xml file and the <url-pattern> therein. If the <url-pattern> is:
/library/myDir/somePage.xxx
then the request's current directory is "/library/myDir" and that directory will be added to the front of the path you specify. If the <url-pattern> is:
/somePage.xxx
then the current directory is "/", and a slash will be added to the front of the path you specify.