synchronized   public   void  sendFile2user(HttpServletResponse response, String fullfileName) throws  ServletException, IOException
  {
      //Выделяем из полного пути файла его имя
      String shortname=fullfileName.substring(fullfileName.lastIndexOf("/")+ 1 , fullfileName.length());
      response.setHeader("Content-Disposition", "attachment; filename=\""+shortname+"\"");
      response.setHeader("Content-Transfer-Encoding","binary;");
      String fileExt=shortname.substring(shortname.lastIndexOf(".")+ 1 ).toString();
      //Выставляем заголовок ответа
      String ContDispType="application/force-download";
       if  (fileExt.toString().equalsIgnoreCase("pdf")) { ContDispType="application/pdf"; }
       if  (fileExt.toString().equalsIgnoreCase("exe")) { ContDispType="application/octet-stream"; }
       if  (fileExt.toString().equalsIgnoreCase("zip")) { ContDispType="application/zip";          }
       if  (fileExt.toString().equalsIgnoreCase("doc")) { ContDispType="application/msword";        }
       if  (fileExt.toString().equalsIgnoreCase("xls")) { ContDispType="application/vnd.ms-excel";   } //   "application/x-xls"
       if  (fileExt.toString().equalsIgnoreCase("ppt")) { ContDispType="application/vnd.ms-powerpoint"; }
       if  (fileExt.toString().equalsIgnoreCase("gif")) { ContDispType="image/gif";   }
       if  (fileExt.toString().equalsIgnoreCase("png")) { ContDispType="image/png";      }
       if  (fileExt.toString().equalsIgnoreCase("jpg")) { ContDispType="image/jpg";       }
       if  (fileExt.toString().equalsIgnoreCase("html")) { ContDispType="text/html";       }
       if  (fileExt.toString().equalsIgnoreCase("htm")) { ContDispType="text/html";          }
       if  (fileExt.toString().equalsIgnoreCase("txt")) { ContDispType="text/plain";          }
       if  (fileExt.toString().equalsIgnoreCase("dbf")) { ContDispType="application/x-dbf";    }

      response.setHeader("Content-Type",ContDispType);
       try {
        BufferedInputStream in= new  BufferedInputStream ( new  FileInputStream(fullfileName));
        BufferedOutputStream binout= new  BufferedOutputStream(response.getOutputStream());
         int  ch=in.read();
         while (ch!=- 1 ){
          binout.write(ch);
          ch=in.read();
        }
        binout.close();
        in.close();
      } catch (IOException ioe){
        ioe.printStackTrace();
      }
  }