How to force file download message box appear????

Question

I download file from oracle
how to set response header to make download message box appear??????
I just see lots of :
���?������ Y�Dl?��>��hn��?g�x~����?7���}��h`a�F��?P?!P��*�X��?/?U ��A?|?/??$�T=��t ��?^!i��f��/?]?�c��7?�UZ�Gz?��SbU��p���Q�T������?��e JyN�/�X^��w��/Bo�k�O��������^��$��?�������yg���C(??[�[+?��R�����p��?te@?��o��?M:D�_s#h�����H��g/?�nE"�PQI���A!��bE������?C`A�������?V��2�^��<�NK?[��k�k$??yJ>?sg-hm�AW(���S��?l[��[���� ��?dL4��6!�N��*���N?Q2?���JoP��>|�sb�_�^�_����~�r��X
on the screen
I am a chinese, happy new year everyone!

Answer 1

and the file.size() is semicode, meaning there isnt a function for it. So you might end up with something like this
     response.setContentType( "application/zip" );
     String fileName = Globals.getAttachmentLocation() + readFile;
     response.setHeader("Content-Disposition", "attachment;filename=" + fileName);
     BufferedInputStream bufferedInputStream = new BufferedInputStream( new FileInputStream( fileName ) );
     ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
     int start = 0;
     int length = 1024;
     byte[] buff = new byte[length];
     while ( bufferedInputStream.read( buff, start, length ) != -1 ) {
          byteArrayOutputStream.write( buff, start, length );
     bufferedInputStream.close();
     response.setContentLength( byteArrayOutputStream.size() );
     response.getOutputStream().write( byteArrayOutputStream.toByteArray() );
     response.getOutputStream().flush();