java code for Send filter

package com.java2s;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

public class SendFilter implements Filter {

private final static String PDF_DIR = "d:\\book\\java2s";

private final static String PDF_CONTENT_TYPE = "application/pdf";

private FilterConfig config;

/** Creates new SessionFilter */
public SendFilter() {
}

public void init(FilterConfig filterConfig) throws ServletException {

System.out.println("Instance created of " + getClass().getName());
this.config = filterConfig;
}

public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws java.io.IOException, ServletException {

//get the file name from the 'file' parameter
String fileName = request.getParameter("file");
if (fileName == null || fileName.equals(""))
throw new ServletException(
"Invalid or non-existent file parameter in SendPdf component.");

if (fileName.indexOf(".pdf") == -1)
fileName = fileName + ".pdf";

ServletOutputStream stream = null;
BufferedInputStream buf = null;
HttpServletResponse httpResp = null;
try {

httpResp = (HttpServletResponse) response;
stream = httpResp.getOutputStream();
File pdf = new File(PDF_DIR + "/" + fileName);

//set response headers
httpResp.setContentType(PDF_CONTENT_TYPE);
httpResp.addHeader("Content-Disposition", "attachment; filename="
+ fileName);
httpResp.setContentLength((int) pdf.length());

FileInputStream input = new FileInputStream(pdf);
buf = new BufferedInputStream(input);
int readBytes = 0;
//read from the file; write to the ServletOutputStream
while ((readBytes = buf.read()) != -1)
stream.write(readBytes);

} catch (Exception ioe) {

// throw new ServletException(ioe.getMessage());
System.out.println(ioe.getMessage());

} finally {

if (buf != null)
buf.close();
if (stream != null) {
stream.flush();
//stream.close();
}

}//end finally
chain.doFilter(request, httpResp);
}

public void destroy() {
/*
* called before the Filter instance is removed from service by the web
* container
*/
}
}