Securely download files in JSP

Question

Hello,
          I need to know how to do the following:
          User logs in, password is compared with database, then user can see a
          list of files in "his" directory (which only he can have access to) and
          download them. For every user there is a separate directory with
          different files.
          Login and all the rest ist done with JSP and working, my problem is I
          just don'T have any idea how to solve the problem with the
          directories/files and downloading them. I would really appreciate any
          help like code samples, links, .. whatever
          Thanks a lot in advance
          Kasper M. Nowak
          

Answer 1

Can you try below code, It should work...
<%
String myFileName = request.getParameter("fileName");
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment; filename=\"" + myFileName + "\"");
String root = "D:/";
InputStream in = null;
ServletOutputStream outs = response.getOutputStream();
try {
in = new BufferedInputStream
(new FileInputStream(root + myFileName));
int ch;
while ((ch = in.read()) != -1) {
outs.print((char) ch);
finally {
if (in != null) in.close(); // very important
outs.flush();
outs.close();
in.close();
%>