Can't get the attachment filename out of a Part (with non ascii characters)

Question

Hello, all and happy new year :)
My issue is with non ascii filename in attachments... Yes i've read the FAQ : http://www.oracle.com/technetwork/java/faq-135477.html#encodefilename
I can't get the filename out of the BodyPart for those kind of attachments
here's my unit test :
     * contains various parts from various mailer encoded in different ways...
     private enum EncodedFileNamePart{
          OUTLOOK("Content-Type: text/plain;\n name=\"=?iso-8859-1?Q?c'estd=E9j=E0no=EBl=E7ac'estcool.txt?=\" \nContent-Transfer-Encoding: 7bit\nContent-Disposition: attachment;\n filename=\"=?iso-8859-1?Q?c'estd=E9j=E0no=EBl=E7ac'estcool.txt?=\" \n\nnoel 2010\n","c'estdéjànoëlçac'estcool.txt"),
          GMAIL("Content-Type: text/plain; charset=US-ASCII; name=\"=?ISO-8859-1?B?ZOlq4G5v62znYWNlc3Rjb29sLnR4dA==?=\"\nContent-Disposition: attachment; filename=\"=?ISO-8859-1?B?ZOlq4G5v62znYWNlc3Rjb29sLnR4dA==?=\"\nContent-Transfer-Encoding: base64\nX-Attachment-Id: f_giityr5r0\n\namluZ2xlIGJlbGxzIQo=\n","déjànoëlçacestcool.txt"),
          THUNDERBIRD("Content-Type: text/plain;\n name=\"=?ISO-8859-1?Q?d=E9j=E0no=EBl=E7acestcool=2Etxt?=\"\nContent-Transfer-Encoding: 7bit\nContent-Disposition: attachment;\n filename*0*=ISO-8859-1''%64%E9%6A%E0%6E%6F%EB%6C%E7%61%63%65%73%74%63%6F;\n filename*1*=%6F%6C%2E%74%78%74\n\njingle bells!\n","déjànoëlçacestcool.txt"),
          EVOLUTION("Content-Disposition: attachment; filename*=ISO-8859-1''d%E9j%E0no%EBl.txt\nContent-Type: text/plain; name*=ISO-8859-1''d%E9j%E0no%EBl.txt; charset=\"UTF-8\" \nContent-Transfer-Encoding: 7bit\n\njingle bells\n","déjànoël.txt"),
          String content=null;
          String target=null;
          private EncodedFileNamePart(String content,String target){
               this.content=content;
               this.target=target;
          public Part get(){
               try{
               ByteArrayInputStream bis = new ByteArrayInputStream(this.content.getBytes());
               Part part = new MimeBodyPart(bis);
               bis.close();
               return part;
               catch(Throwable e){
                    return null;
          public String getTarget(){
               return this.target;
     @Test
     public void testJavamailDecode() throws MessagingException, UnsupportedEncodingException{
          System.setProperty("mail.mime.encodefilename", "true");
          System.setProperty("mail.mime.decodefilename", "true");
          for(EncodedFileNamePart part : EncodedFileNamePart.values())
               assertEquals(part.name(),MimeUtility.decodeText(part.get().getFileName()),part.getTarget());     
I take a NullPointerExcepion in the decodeText because getFileName() return null for the EVOLUTION case, and work well with OUTLOOK, THUNDERBIRD and GMAIL.
Evolution's content type is "Content-Disposition: attachment; filename*=ISO-8859-1''d%E9j%E0no%EBl.txt" wich doesn't look like the other (looks like the RFC 2616 or RFC5987 to do it.)
How can i handle this situation except by writting my own decoder?
Thanks for your answers!
Edited by: user13619058 on 4 janv. 2011 07:44

Answer 1

Set the System property "mail.mime.decodeparameters" to "true" to enable the RFC 2231 support.
See the javadocs for the javax.mail.internet package for the list of properties.
Yes, the FAQ entry should contain those details as well.