error in downloading file

[sameera liyanage]

here is a code for downloading jar file

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class ShowHeadersServlet extends HttpServlet {

	public void doGet(HttpServletRequest req, HttpServletResponse res)
			throws ServletException, IOException {

		res.setContentType("application/jar");
		File f = new File("bootstrap.jar");
		byte[] bytearray = new byte[(int) f.length()];
		FileInputStream is = new FileInputStream(f);
		is.read(bytearray);
		OutputStream os = res.getOutputStream();

		os.write(bytearray);
		os.flush();
	}
}

here is the web.xml file

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">


<servlet>
<servlet-name>A</servlet-name>
<servlet-class>ShowHeadersServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>A</servlet-name>
<url-pattern>/A</url-pattern>
</servlet-mapping>



</web-app>

first i compile the ShowHeadersServlet class and put it to the
C:\Tomcat\apache-tomcat-6.0.18\webapps\hellow\WEB-INF\classes.
then i start the tomcat server.
then go to browser and type this.

http://localhost:8080/hellow/A
it downloading some file named A. But it is not a file which i need.
Actually downloaded file name is equal to the last name of the URl which i typed in browser.
i need to download the bootstrap.jar file.
Also I put this jar to the bin director in tomcat.
What is wrong with this code ?

[Ankit Garg]

Use the Content-Disposition header...

[sameera liyanage]

no, i don't need a hiperlink in the broser.
I need to download the file when i put the relavant URl in browser.
The problem is that it download the file which is not expected and the name of the file is last name of URL.

if the URL type is http://localhost:8080/hellow/HelloWorldServlet
downloaded file name is HelloWorldServlet

if the URL type is http://localhost:8080/hellow/A
downloaded file name is A(I change the web.xml also to a when i chang the URL)

I check the size of the downloaded file with my expected bootstrap.jar.
bootstrap.jar size is 17.1 KB
downloaded file size is 70.4 KB.

[Ankit Garg]

First of all I didn't say that you need a hyperlink. You need to set the content-disposition header in the servlet whose code you just showed. Also where is your jar file actually located?? You are using only the jar name in the File class constructor. You should try to use the inbuilt mechanism in servlets like getResourceAsStream to read files from web application's directory. Read this thread or a tutorial like this for more info...

[sameera liyanage]

i put that jar file to the tomcat/bin folder.

[Ulf Dittmer]

In a web app, relative paths (like "bootstrap.jar") don't work, because there is no notion of a default directory. You need to use an absolute path - the "ServletContext.getRealPath" method will be helpful for that.