java attach file from virtual filesystem to email

Question

I am using a virtual filesystem and I'd like to attach a file from it to an email. However, the MimeBodyPart object only takes Files, which don't work on a default filesystem like jimfs. See my code below, where I get an UnsupportedOperation exception when I try to convert to file.

public Email attach(Path file){
    MimeBodyPart attachment = new MimeBodyPart()
    attachment.attachFile(file.toFile())
    attachments.add(attachment)
    return this
}

Answer 1

Since jimfs files aren't really files, you can't use the File APIs.

A simple workaround is to use ByteArrayDataSource, which will copy the data.

A better approach would be to write your own PathDataSource that's similar to FileDataSource but uses Files.newInputStream instead of FileInputStream. Then attach the file using:

MimeBodyPart mbp = new MimeBodyPart();
mbp.setDataHandler(new DataHandler(new PathDataSource(path)));
mbp.setFileName(path.getFileName().toString());
mbp.setDisposition(Part.ATTACHMENT);