/*

PLACE THIS CODE IN THE APPLET:

import java.net.URLConnection;
import java.net.URL;

import java.io.BufferedOutputStream;
import java.io.BufferedInputStream;


	private void saveFile (byte[] bytes, String file_name)
	{
		try
		{
			URL url = new URL
			(
				getDocumentBase (),
				"path.to.servlet" + "?file_name=" + file_name
			);

			URLConnection url_c = url.openConnection();
			url_c.setDoOutput  (true);
			url_c.setDoInput   (true);
			url_c.setUseCaches (false);
			url_c.setDefaultUseCaches(false);
			url_c.setRequestProperty("Content-Type", "application/octet-stream");

			BufferedOutputStream bos = new BufferedOutputStream(url_c.getOutputStream());

			bos.write (bytes);
			bos.flush();
			bos.close();


			BufferedInputStream bis = new BufferedInputStream (url_c.getInputStream());
			byte buf [] = new byte[1024];
			String msg = "";
			for (int i = 0; i > -1; i = bis.read(buf)) msg += new String(buf, 0, i);
			bis.close();

			System.out.println(msg);
		}
		catch (Throwable t)
		{
			System.out.println(t.toString());
		}
	}


*/




import java.io.IOException;
import java.io.PrintStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;



public class save2disk extends HttpServlet
{



	private final String

		aok_message = "file saved on network!",
		nok_message = "file not saved: parameters wrong",

		base_directory = "the.folder.to.save.the.file.in";


	private String

		user;


	/*


	private void doLogin
	(
		HttpServletRequest request,
		user,
		pass
	)
	{
		if (user.equals ("username) && pass.equals ("secretpassword"))
		{
			HttpSession session = request.getSession (true);
			session.setAttribute ("logon.isDone", (Object) user);
			// deprecated: session.putValue ("logon.isDone", user);
		}
	}
¨

	*/

	// this one assumes some sort of logon procedure like the one above:

	private boolean isLoggedIn
	(
		HttpServletRequest request
	)
	{
		HttpSession session = request.getSession (true);
		String check_user = (String) session.getAttribute ("logon.isDone");
		if (check_user == null)
		{
			return false;
		}
		else
		{
			user = check_user;
			return true;
		}
	}


	// to remove funny characters from the input - we don't want anybody
	// stepping out of the base directory
	private String strip (String str)
	{
		if (str != null)
		{
			  str = str.substring (str.lastIndexOf ("\\") + 1);
			  str = str.substring (str.lastIndexOf ("/") + 1);
		}
		return str;
   }

	public void service
	(
		HttpServletRequest request,
		HttpServletResponse response
	)
	throws ServletException, IOException
	{
		String file_name = strip (getFormParam (request, "file_name"));
		if
		(
			isLoggedIn ( request) &&
			copy
			(
				request.getInputStream(),
				base_directory + "/" + user + "/" + file_name
			)
		)

	   	reply
	   	(
			response,
			"message from " +
			getServletConfig().getServletContext().getServerInfo() + ":\n" +
			aok_message
		);
		else reply
	   	(
			response,
			"message from " +
			getServletConfig().getServletContext().getServerInfo() + ":\n" +
			nok_message
		);
	}

	private boolean copy
	(
		InputStream is,
		String new_file
	)
	{
		try
		{
			FileOutputStream fos = new FileOutputStream ( new_file );

			int count;
			int counter = 0;
			int max = 25; // setting a 100 k max size on the file
			byte [] buf = new byte [4096];

			while ((count = is.read(buf, 0, buf.length)) != -1 && counter++ < max)
				fos.write (buf, 0, count);

			fos.flush();
			fos.close();
			is.close();
			return true;
		}
		catch (Throwable t)
		{
			return false;
		}
	}


	private void reply
	(
		HttpServletResponse response,
		String msg
	)
	throws IOException
	{
		response.setContentType("text/html");
 		PrintStream ps = new PrintStream ( response.getOutputStream() );
		ps.print (msg);
		ps.flush();
		ps.close();
	}


	private String getFormParam
	(
		HttpServletRequest request,
		String name
	)
	{
		String str = request.getParameter (name);
		return (str != null) ? str : new String ();
	}
}