Someone knows a mail (SMTP) delivery library for Java?

Question

I\'d like to send mail without bothering with the SMTP-Server which is used for delivery.

So JavaMail API doesn\'t work for me because I have to specify a SMTP server to

Answer 1

One possible solution: get the MX record on your own and use JavaMail API.

You can get the MX record using the dnsjava project:

Maven2 dependency:

    dnsjava
    dnsjava
    2.0.1

Method for MX record retrieval:

public static String getMXRecordsForEmailAddress(String eMailAddress) {
    String returnValue = null;

    try {
        String hostName = getHostNameFromEmailAddress(eMailAddress);
        Record[] records = new Lookup(hostName, Type.MX).run();
        if (records == null) { throw new RuntimeException("No MX records found for domain " + hostName + "."); }

        if (log.isTraceEnabled()) {
            // log found entries for debugging purposes
            for (int i = 0; i < records.length; i++) {
                MXRecord mx = (MXRecord) records[i];
                String targetString = mx.getTarget().toString();
                log.trace("MX-Record for '" + hostName + "':" + targetString);
            }
        }

        // return first entry (not the best solution)
        if (records.length > 0) {
            MXRecord mx = (MXRecord) records[0];
            returnValue = mx.getTarget().toString();
        }
    } catch (TextParseException e) {
        throw new RuntimeException(e);
    }

    if (log.isTraceEnabled()) {
        log.trace("Using: " + returnValue);
    }
    return returnValue;
}

private static String getHostNameFromEmailAddress(String mailAddress) throws TextParseException {
    String parts[] = mailAddress.split("@");
    if (parts.length != 2) throw new TextParseException("Cannot parse E-Mail-Address: '" + mailAddress + "'");
    return parts[1];
}

Sending mail via JavaMail code:

public static void sendMail(String toAddress, String fromAddress, String subject, String body) throws AddressException, MessagingException {
    String smtpServer = getMXRecordsForEmailAddress(toAddress);

    // create session
    Properties props = new Properties();
    props.put("mail.smtp.host", smtpServer);
    Session session = Session.getDefaultInstance(props);

    // create message
    Message msg = new MimeMessage(session);
    msg.setFrom(new InternetAddress(fromAddress));
    msg.setRecipient(Message.RecipientType.TO, new InternetAddress(toAddress));
    msg.setSubject(subject);
    msg.setText(body);

    // send message
    Transport.send(msg);
}