Home / FAQ / Server-Side Development / JavaMail

Michael Dailous

Generally speaking, any email message that contains an attachment is encoded as a multipart/* email message. Even if there is no main "body" part, the email is still encoded as a multipart/* email message. You would process each part of the message just as you would any other multipart/* message. Here's a quick snippet of code that'll go through as many levels of multipart/* sections as available (NOTE: This is a _quick_ code snippet and does not do any error detection/correction):

// create a session
// connect to the store
// open the folder
// get the message
getPartMimeType(message.getContent());

public void getPartMimeType(Part p) {
    if (p.isMimeType("multipart/*")) {
        Multipart mp = (Multipart)p.getContent();
        for (int x = 0; x < mp.getCount(); x++) {
            if (mp.getBodyPart(x).isMimeType("multipart/*")) {
                getPartMimeType(mp.getBodyPart(x).getContent());
            } else {
                System.out.println(mp.getBodyPart(x).getContentType());
            }
        }
    } else {
        // you should do more granular checking of other mime-types
        System.out.println(p.getContentType());
    } 
}

This should print out the MIME type of each part of the email message, no matter how many multipart/* parts there are.

If you'd like to determine the MIME type of just the first attachment, you could modify the above code snippet as follows:

// create a session
// connect to the store
// open the folder
// get the message
getAttachmentMimeType(message.getContent());

public void getAttacheMimeType(Part p) {
    if (p.isMimeType("multipart/*")) {
        Multipart mp = (Multipart)p.getContent();
        for (int x = 0; x < mp.getCount(); x++) {
            if (mp.getBodyPart(x).isMimeType("multipart/*")) {
                getAttachmentMimeType(mp.getBodyPart(x).getContent());
            } else {
                if (checkAttachment(mp.getBodyPart(x).getDisposition())) {
                    System.out.println(mp.getBodyPart(x).getContentType());
                    break;
                }
            }
        }
    } else {
        // you should do more granular checking of other mime-types
        if (checkAttachment(p.getDisposition())) {
            System.out.println(p.getContentType());
        }
    } 
}

public boolean checkAttachment(String disposition, String contentType) {
    if (disposition != null && disposition.equalsIgnoreCase(Part.ATTACHMENT)) {
        return true;
    }
    return false;
}