dcsimg

I have to implement a download module wherein I have to give only registered users the requested files.

Created May 7, 2012

James Johnson

 

 

Kishore, try this servlet:


import java.io.*;
import javax.servlet.http.*;
import javax.servlet.*;

/**
 * Serves a file from the disk.
 */
public class FileServerServlet extends HttpServlet
{
    /**
     * Receives and responds to requests.
     */
    public void service(HttpServletRequest req, HttpServletResponse res)
        throws ServletException, IOException
    {
	String error = null;
	HttpSession ses = null;
	String company = DoAuthorizaton(req);
    	
	
    	

        if (company != null)
        {
            InputStream fis = null;
            OutputStream out = res.getOutputStream();
            String filename = req.getParameter("filename");
	    res.setContentType("application/x-download");
	    res.setHeader("Content-Disposition", "attachment; filename=" + filename);


			String filepath = "c:webfiles";
			filename = filepath + filename;
            fis = new BufferedInputStream(
                new FileInputStream(filename));

            byte[] buffer = new byte[1024];
            int bytes = -1;
            while ((bytes = fis.read(buffer, 0, buffer.length)) != -1)
            {
                out.write(buffer, 0, bytes);
            }
        }
        
	if(error != null)
        {
            PrintWriter out = res.getWriter();
            res.setContentType("text/html");
            out.println("<html><body>
");
            out.println("File cannot be served at the moment:");
	    out.println("
" + error);
            out.println("
</body></html>");
        }
    }

    private String DoAuthorizaton(HttpServletRequest req)
    	{
           HttpSession session = req.getSession(false);
           if(session != null)
           {
            String company = (String) session.getAttribute("company");
            return company;
           } 
         return null;
    	}
}



Name this file some servlet name like: "fileServer"

you can link to a jsp page (with the link text as the file name) that checks for a session like: checkSession.jsp?filename=file.txt

then if the session is there, forward the request onto the servlet with the file name like: fileServer?filename=file.txt&session=ok

modify the "c:webfiles" directory in the code to reflect your file storage directory on your hard drive.

Hope this helps...


James