How to download a file from server to client m/c

Question

hi
my requirement is,
a form is displayed to user with a download button and
onclick of download ,user will see a box with options open,save,cancel.
if user clicks on open /save ,how to get the info about download is complete on client side because i need to set a flag in database ,
as Downloaded once the download is complete on client side
my problem is ,in the action of form the path given is of servlet class
having code of
setheader and setcontenttype as attachment but on click of download button it is opening the servlet instead of the required file,
means it is opening the page specified in action of form ,
what can be done abt it??/

Answer 1

Please post your code using code tags (click on CODE above the text area, when posting)
response.setContentType("application/octet-stream");Why octet-stream? Set the correct mime-type.
String disHeader = "Attachment; Filename=\"filename\"";The filename should just be the file's name. Not the complete path to the file! This will tell anyone where the file is located on the server. It's also inconvenient because by default,the browser will suggest it as the name for the download.
Your way of writing to the output stream is just plain wrong. See this snippet (picked from [http://balusc.blogspot.com/2007/07/fileservlet.html])
        BufferedInputStream input = null;
        BufferedOutputStream output = null;
        try {
            // Open streams.
            input = new BufferedInputStream(new FileInputStream(file), DEFAULT_BUFFER_SIZE);
            output = new BufferedOutputStream(response.getOutputStream(), DEFAULT_BUFFER_SIZE);
            // Write file contents to response.
            byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
            int length;
            while ((length = input.read(buffer)) > 0) {
                output.write(buffer, 0, length);
            // Finalize task.
            output.flush();
        } finally {
            // Gently close streams.
            close(output);
            close(input);
        }