Est-il possible d'envoyer du courrier avec Javamail sans authentification?

C'est possible, mais vous avez besoin de rechercher vous-même les enregistrements MX dans le DNS. Vous pouvez utiliser dnsjava-2.16.jar de la bibliothèque. Ajouter dnsjava et javax.mail bibliothèques de chemin de compilation pour compiler l'exemple de code suivant. Vérifiez votre dossier de spam après avoir tenté de livrer le message de cette manière: car il n'y a pas de signature DKIM, et l'adresse IP que vous utilisez pour envoyer l'e-mail n'appartiennent pas à des adresses autorisées pour cet hôte ("yourhost.org"), la réception d'e-mails du serveur sera susceptible de mettre l'e-mail dans le dossier spam.

import com.sun.mail.smtp.SMTPSendFailedException;
import com.sun.mail.smtp.SMTPSenderFailedException;
import com.sun.mail.util.MailConnectException;
import org.xbill.DNS.*;

import javax.mail.Message;
import javax.mail.*;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import java.util.Properties;

public class SendEmail {
        String Subject = "Email subject!";
        Template template;
        Properties properties;
        String hostname = "yourhost.org"; //the host to send email from
        String to;
        String fromEmal;
        String fromName = "Your name";

        SendEmail(String from,String to){
            this.to = to;
            this.fromEmal = from;
            this.properties = new Properties();
            this.properties.put("mail.transport.protocol", "smtp");
            this.properties.put("mail.smtp.host", getMXRecordsForEmailAddress(to)); //SMTP Server
            this.properties.put("mail.smtp.port","25");
            this.properties.put("mail.smtp.localhost", hostname); //HELO host
            this.properties.put("mail.smtp.from",from);//SMTP MAIL FROM
            this.properties.put("mail.smtp.allow8bitmime","true");

           //this.properties.put("mail.smtp.localaddress","192.168.1.44"); //Connect from this IP
            sendMessage();
        }


        public void sendMessage() {

            try{

                Session session = Session.getInstance(this.properties);
                MimeMessage msg = new MimeMessage(session);

                msg.setFrom(new InternetAddress("\""+this.fromName+"\""+"<"+this.fromEmal+">"));
                msg.addRecipient(Message.RecipientType.TO,
                        new InternetAddress(this.to));

                msg.setSubject(this.Subject);

                msg.setContent("Email body <b>with HTML</b>","text/html; charset=utf-8");

                Transport.send(msg);
                System.out.println("Message sent OK");


            }catch (AddressException e){
                System.out.println("Bad address format: "+e.getRef());
            }catch (SMTPSenderFailedException e){
                System.out.println(e.getReturnCode() + ": We can't send emails from this address: " + e.getAddress());
            }catch (NoSuchProviderException e){
                System.out.println(e.getMessage()+": No such provider");
            }catch (SMTPSendFailedException e){
                System.out.print(e.getReturnCode() + ": " + e.getMessage());
            }catch (MailConnectException e){
                System.out.println("Can't connect to "+ e.getHost()+":"+e.getPort());
            }
            catch(MessagingException e){
                System.out.println("Unknown exception"+e);
            }catch (Exception e){
                System.out.println(e);
            }

        }


    public  String getMXRecordsForEmailAddress(String eMailAddress) {
        String returnValue = new String();

        try {
            String parts[] = eMailAddress.split("@");
            String hostName = parts[1];

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

            if (records.length > 0){
                MXRecord mxr = (MXRecord) records[0];
                for (int i = 0; i< records.length; i++){
                    MXRecord tocompare = (MXRecord)records[i];
                    if (mxr.getPriority() > tocompare.getPriority())
                        mxr = tocompare;
                }
                returnValue = mxr.getTarget().toString();
            }

        } catch (TextParseException e) {
            return new String("NULL");

        }

        return returnValue;
    }

}

OriginalL'auteur Serge Rogatch