how to download file from server through servlet

i want to download a file from server through servlet using inputstream.
if any one have any code plz help me.

What are your requirements? You just want them to make a request to a servlet and the servlet sends them the file?

There was a similar discussion here, but the solution I quite liked was to use the RequestDiospatcher. You may need to set the filename and content type first.

Otherwise you can read from a FileInputStream and write to the OutputStream, but you would still need the filename and content type to be set.

It is better to continue conversations here rather than emailing people. You were lucky, I usually don't check that address for days at a time...

--------------------------------------
From email:
i have download this code but i don't know how to use this.

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.SocketException;
import java.net.URL;
 
import javax.servlet.ServletException;
import javax.servlet.UnavailableException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
public class TestServ extends HttpServlet
{
    Exception exception;
 
    public void doGet(HttpServletRequest req, HttpServletResponse res)
        throws ServletException, IOException, UnavailableException
    {
 
        int bytesRead = 0;
        int count = 0;
        byte[] buff = new byte[1];
 
        OutputStream out = res.getOutputStream();
 
        //---------------------------------------------------------------
        // Set the output data's mime type
        //---------------------------------------------------------------
 
        res.setContentType("application/pdf");//application/pdf" ); // MIME
                                              // type for pdf doc
 
        //---------------------------------------------------------------
        // create an input stream from fileURL
        //---------------------------------------------------------------
 
        String fileURL = "http://localhost:7001/soap.pdf";
 
        //------------------------------------------------------------
        // Content-disposition header - don't open in browser and
        // set the "Save As..." filename.
        // *There is reportedly a bug in IE4.0 which ignores this...
        //------------------------------------------------------------
 
        //-----------------------------------------------------------------
        // PROXY_HOST and PROXY_PORT should be your proxy host and port
        // that will let you go through the firewall without authentication.
        // Otherwise set the system properties and use
        // URLConnection.getInputStream().
        //-----------------------------------------------------------------
        BufferedInputStream bis = null;
        BufferedOutputStream bos = null;
        boolean download = false;
 
        res.setHeader("Content-disposition", "attachment; filename=xml.pdf;");
 
        try
        {
 
            URL url = new URL(fileURL);
            bis = new BufferedInputStream(url.openStream());
            bos = new BufferedOutputStream(out);
 
            while (-1 != (bytesRead = bis.read(buff, 0, buff.length)))
            {
                try
                {
                    bos.write(bytesRead);
                    bos.flush();
                }//end of try for while loop
                catch (SocketException e)
                {
                    setError(e);
                    break;
                }
                catch (Exception e)
                {
                    System.out.println("Exception in while of TestServlet is " + e.getMessage());
                    if (e != null)
                    {
                        System.out.println("File not downloaded properly");
 
                        setError(e);
                        break;
 
                    }//if ends
 
                }//end of catch for while loop
 
            }//while ends
 
            Exception eError = getError();
 
            if (eError != null)
            {
 
                System.out.println("\n\n\n\nFile Not DownLoaded properly\n\n\n\n");
            }
            else if (bytesRead == -1)
            {
                System.out.println("\n\n\n\ndownload successful\n\n\n\n");
 
            }
            else
            {
                System.out.println("\n\n\n\ndownload not successful\n\n\n\n");
            }
 
        }
        catch (MalformedURLException e)
        {
            System.out.println("Exception inside TestServlet is " + e.getMessage());
 
        }
        catch (IOException e)
        {
            System.out.println("IOException inside TestServlet is " + e.getMessage());
        }
 
        finally
        {
            try
            {
                if (bis != null)
                    bis.close();
                if (bos != null)
                    bos.close();
            }
            catch (Exception e)
            {
                System.out.println("here =" + e);
            }
        }
 
    }//doPost ends
 
    public void setError(Exception e)
    {
        exception = e;
        System.out.println("\n\n\nException occurred is " + e + "\n\n\n");
 
    }
 
    public Exception getError()
    {
        return exception;
    }
}//class ends

I have formatted the code and cleaned it a little. There are some key problems with this code, I suggest you don't use it.

The bits you are interested in look like this:

Essentially you set the content type and 'filename' on the response. The lines for these should be obvious. You use a FileInputStream of some other type of stream to suck in a file, then pump it down the OutputStream. When you run out of data, stop.

Actually there is a bug in the bos.write(bytesRead) line, that's not right at all. Icky code.

If the file is available on the context, you could also try:

I haven't tried this, but it appeals to me.