I have written a Java web application that allows a user to download files from a server. These files are quite large and so are zipped together before download.
It works like this:
1. The user gets a list of files that match his/her criteria
2. If the user likes a file and wants to download he/she selects it by checking a checkbox
3. The user then clicks "download"
4. The files are then zipped and stored on a server
5. The user this then presented with a page which contains a link to the downloadable zip file
6. However on downloading the zip file the file that is downloaded is 0 bytes in size
I have checked the remote server and the zip file is being created properly, all that is left is to serve the file the user somehow, can you see where I might be going wrong, or suggest a better way to serve the zip file.
The code that creates the link is:
<%
String zipFileURL = (String) request.getAttribute("zipFileURL"); %>
<p><a href="<% out.print(zipFileURL); %> ">Zip File Link</a></p>
The code that creates the zipFileURL variable is:
public static
String zipFiles(ArrayList<String> fileList,
String contextRootPath) {
//time-stamping
Date date = new Date();
Timestamp timeStamp = new Timestamp(date.getTime());
Iterator fileListIterator = fileList.iterator();
String zipFileURL = "";
try {
String ZIP_LOC = contextRootPath + "WEB-INF" + SEP + "TempZipFiles" + SEP;
BufferedInputStream origin = null;
zipFileURL = ZIP_LOC
+ "FITS." + timeStamp.toString().replaceAll(":", ".").replaceAll(" ", ".") + ".zip";
FileOutputStream dest = new FileOutputStream(ZIP_LOC
+ "FITS." + timeStamp.toString().replaceAll(":", ".").replaceAll(" ", ".") + ".zip");
ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(
dest));
// out.setMethod(ZipOutputStream.DEFLATED);
byte data[] = new byte[BUFFER];
while(fileListIterator.hasNext()) {
String fileName = (String) fileListIterator.next();
System.out.println("Adding: " + fileName);
FileInputStream fi = new FileInputStream(fileName);
origin = new BufferedInputStream(fi, BUFFER);
ZipEntry entry = new ZipEntry(fileName);
out.putNextEntry(entry);
int count;
while ((count = origin.read(data, 0, BUFFER)) != -1) {
out.write(data, 0, count);
}
origin.close();
}
out.close();
} catch (Exception e) {
e.printStackTrace();
}
return zipFileURL;
}
