Download Page - JSP

<%

/**   ================================================================

      Mobicator

      ----------------------------------------------------------------

      @description {file} Parameter로 지정한 Id에 해당하는 file을 Download

                        * CAUTION: 본 JSP File은 File을 Download하는 File이므로

                         임의로  '% >'와 '< %'사이를 띄우거나 CR/LF를 줘서는 안된다.

      @param

            file Download할 File의 Id

      @include

            N/A

      @usage

            /download.jsp?file={file_id}

      @author pluto

      @date 2008. 02. 20

      ================================================================

*/

%><%@ page language="java" contentType="application/unknown; charset=UTF-8" pageEncoding="UTF-8"

%><%-- All of Import here

--%><%@page import="java.io.File"

%><%@page import="java.io.InputStream"

%><%@page import="java.io.OutputStream"

%><%@page import="java.io.FileInputStream"

%><%@page import="java.io.BufferedOutputStream"

%><%@page import="java.io.BufferedInputStream"

%><%@page import="java.io.UnsupportedEncodingException"

%><%!

      private int DEFAULT_BUFFER_SIZE                 = 2048;

      private String HEAD_CONTENT_TYPE                = "Content-Type";

      private String HEAD_CONTENT_DISPOSITION         = "Content-Disposition";

      private String HEAD_CONTENT_TRANSFER_ENCODE     = "Content-Transfer-Encoding";

      private String HEAD_PRAGMA                            = "Pragma";

      private String HEAD_EXPIRES                           = "Expires";

      private String HEAD_CONTENT_LENGTH              = "Content-Length";

      private String CONTENT_TYPE_MATTER              = "doesn/matter;";

      private String CONTENT_TYPE_OCTET               = "application/octet-stream;";

      private String CONTENT_TRANSFER_ENCODE          = "binary;";

      private String PRAGMA                                 = "no-cache;";

      private String EXPIRES                                = "-1";

      private String USER_AGENT                             = "USER-AGENT";

      private String ENCODING                               = "UTF-8";

      private String CHAR_SET                               = "charset=" + ENCODING + ";";

      private String FILE_NAME                              = "filename=";

      private String ATTACHMENT                             = "attachment;";

      private String LOCAL_PATH                             = "/localPath/";

      private String MSIE_4                                 = "MSIE 4";

      private String MSIE_5_5                               = "MSIE 5.5";

      private String FIRE_FOX                               = "Firefox";

      public String getFileName( String fileName, String ua ) throws UnsupportedEncodingException {

            if( ua.indexOf( FIRE_FOX ) >= 0 ) {

                  return fileName;

            } else {

                 return java.net.URLEncoder.encode( fileName, "UTF-8" ).replaceAll( "\\+", "%20" );

            }

      }

%><%

      InputStream                   inStream = null;

      OutputStream                  outStream = null;

      byte[]                              buffer = null;

      String                              docBase = getServletContext().getRealPath( "/" );

      String                              ua = request.getHeader( USER_AGENT );

      String                              id = request.getParameter( "file" );

      String                              url = request.getRequestURL().toString();

      File                          downloadFile = new File( LOCAL_PATH + id );

      String                              fileName = getFileName( downloadFile.getName(), ua );

      if( ua.indexOf( MSIE_4 ) >= 0 || ua.indexOf( MSIE_5_5 ) >= 0 ) {

            response.setHeader( HEAD_CONTENT_TYPE, CONTENT_TYPE_MATTER + CHAR_SET );

            response.setHeader( HEAD_CONTENT_DISPOSITION, FILE_NAME + fileName + ";" );

      } else {

            response.setHeader( HEAD_CONTENT_TYPE, CONTENT_TYPE_OCTET + CHAR_SET );

            response.setHeader( HEAD_CONTENT_DISPOSITION, ATTACHMENT + FILE_NAME + fileName + ";" );

      }

      response.setHeader( HEAD_CONTENT_TRANSFER_ENCODE, CONTENT_TRANSFER_ENCODE );

      response.setHeader( HEAD_PRAGMA, PRAGMA );

      response.setHeader( HEAD_EXPIRES, EXPIRES );

      response.setHeader( HEAD_CONTENT_LENGTH, String.valueOf( downloadFile.length() ) );

      if( downloadFile.isFile() ) {

            try {

                  inStream = new BufferedInputStream( new FileInputStream( downloadFile ) );

                  outStream = new BufferedOutputStream( response.getOutputStream() );

                  buffer = new byte[ DEFAULT_BUFFER_SIZE ];

                  int                           bufferSize = 0;

                  while( (bufferSize = inStream.read( buffer )) != -1 ) {

                        outStream.write( buffer, 0, bufferSize );

                        outStream.flush();

                  }

            } catch( Exception e ) {

                  e.printStackTrace();

            } finally {

                  if( inStream != null ) {

                        inStream.close();

                  }

            }

      }

%>