Re: Call URL with session

Lothar Kimmeringer <>
Fri, 16 Oct 2009 09:34:20 +0200
Pif wrote:

Hello, I want to save a URL in a file. I open the URL and I get it as
an inputstream that I write on disk.

This is done in the servlet. I can get the session in the parameters,
but what should I do to transmit the session to the server. Here is my
current code :

URL url = new URL("..... my url ....");
URLConnection connection = url.openConnection();
InputStream is = url.openStream();

You can leave away url.openConnection() or use

As John said, you simply write it to a file. Instead of a
Writer you can do a binary save:

byte[] buf = new byte[4096];
FileOutputStream fos = new FileOutputStream(filename);
int read;
while ((read = != -1){
  fos.write(buf, 0, read);

Bytewise read and write takes a lot more time than above
blockwise read and write.

That will keep binary data like images or PDF-files intact.
If it is text you need to do the conversion afterwards.

If you need that information you should use url.openConnection()
instead of url.openStream() instead and parse the content-type
header in the response. If you have j2ee or the activation.jar
in your classpath you can do it this way:

MimeType mt = new MimeType(connection.getHeaderField("Content-Type"));
String charset = mt.getParameter("charset");
if (charset == null){
  charset = "8859_1";

After that you open an InputStreamReader with above charset
and write it to a file with the charset of your choice
(by using OutputStreamWriter with an embedded FileOutputStream,
don't use FileWriter, it used the System-encoding which might
be not what you want).

BTW: It's possible that connection.getContentEncoding() also
returns the charset (and not the transfer-encoding e.g. BASE64),
so you should check that out first.

Regards, Lothar
Lothar Kimmeringer E-Mail:
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