Send filter : Filter « Servlets « Java

Send filter

package com.java2s;


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, 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.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 = != -1)

    } catch (Exception ioe) {

      //  throw new ServletException(ioe.getMessage());

    } finally {

      if (buf != null)
      if (stream != null) {

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

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


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