Reading a remote file using Java

Question

I am looking for an easy way to get files that are situated on a remote server. For this I created a local ftp server on my Windows XP, and now I am trying to give my test applet the following address:

try
{
    uri = new URI("ftp://localhost/myTest/test.mid");
    File midiFile = new File(uri);
}
catch (Exception ex)
{
}

and of course I receive the following error:

URI scheme is not "file"

I've been trying some other ways to get the file, they don't seem to work. How should I do it? (I am also keen to perform an HTTP request)

Answer 1

You can't do this out of the box with ftp.

If your file is on http, you could do something similar to:

URL url = new URL("http://q.com/test.mid");
InputStream is = url.openStream();
// Read from is

If you want to use a library for doing FTP, you should check out Apache Commons Net

Answer 2

Reading binary file through http and saving it into local file (taken from here):

URL u = new URL("http://www.java2s.com/binary.dat");
URLConnection uc = u.openConnection();
String contentType = uc.getContentType();
int contentLength = uc.getContentLength();
if (contentType.startsWith("text/") || contentLength == -1) {
  throw new IOException("This is not a binary file.");
}
InputStream raw = uc.getInputStream();
InputStream in = new BufferedInputStream(raw);
byte[] data = new byte[contentLength];
int bytesRead = 0;
int offset = 0;
while (offset < contentLength) {
  bytesRead = in.read(data, offset, data.length - offset);
  if (bytesRead == -1)
    break;
  offset += bytesRead;
}
in.close();

if (offset != contentLength) {
  throw new IOException("Only read " + offset + " bytes; Expected " + contentLength + " bytes");
}

String filename = u.getFile().substring(filename.lastIndexOf('/') + 1);
FileOutputStream out = new FileOutputStream(filename);
out.write(data);
out.flush();
out.close();