[JavaMail] resend the message using a different SMTP server?

[mrby]

Hi, guys:

A problem about JavaMail, how could I resend
a message using a different SMTP server?

This is the my code snippet:
....
Properties props = new Properties();
debug.op("email.send: host=" + host );
props.put("mail.smtp.host", host );
Session session = Session.getDefaultInstance(props, null);
try {
// create a message
Message msg = new MimeMessage(session);
msg.setFrom(new InternetAddress(from));
msg.setRecipients( Message.RecipientType.TO,
InternetAddress.parse(total_to_list) );
msg.setSubject(subject);
msg.setText(total_message);
Transport.send(msg);
}
catch (MessagingException mex) {
// If exception occurs here, I want to change the SMTP
// server and resend the message. How could I do?
// Is there a nice way besides retyping those code?
}

Thanks much!

 

[Roedy Green]

A problem about JavaMail, how could I resend
a message using a different SMTP server?

Do you mean send the message to two different SMTP servers, or pick it
up from one server and relay it to another?

 

[mrby]

Yes. I mean send the message to two different SMTP servers.

 

[Roedy Green]

Properties props = new Properties();
debug.op("email.send: host=" + host );
props.put("mail.smtp.host", host );
Session session = Session.getDefaultInstance(props, null);
try {
// create a message
Message msg = new MimeMessage(session);
msg.setFrom(new InternetAddress(from));
msg.setRecipients( Message.RecipientType.TO,
InternetAddress.parse(total_to_list) );
msg.setSubject(subject);
msg.setText(total_message);
Transport.send(msg);

You need TWO session objects. What is a big infuriating is the session
gets built into the Message. If I were designing JavaMail I would not
have a Session at all. You would simply specify the Session info to
the Transport constructor. But that is not how they did it.

So you have to put the body of the program in a method, and pass it
the session. Then call it twice with two different sessions or two
diffrent smtp hosts, and have the method create the session.

 

[GaryM]

You need TWO session objects. What is a big infuriating is the session
gets built into the Message. If I were designing JavaMail I would not
have a Session at all. You would simply specify the Session info to
the Transport constructor. But that is not how they did it.

So you have to put the body of the program in a method, and pass it
the session. Then call it twice with two different sessions or two
diffrent smtp hosts, and have the method create the session.

I tested something like this before, as IIRC you can just set the
"mail.smtp.host" property again without needed to creating another
Session object. These would assume sequential sending with the property
changing in between sends.

If that does not work, then the original poster should rememeber to do
Session.getInstance as opposed to Session.getDefaultInstance() to ensure
he/she has distinct objects.

 

[mrby]

You need TWO session objects. What is a big infuriating is the session
gets built into the Message. If I were designing JavaMail I would not
have a Session at all. You would simply specify the Session info to
the Transport constructor. But that is not how they did it.

So you have to put the body of the program in a method, and pass it
the session. Then call it twice with two different sessions or two
diffrent smtp hosts, and have the method create the session.

Thanks much!
Now I see I should put those code into a separate method.

 

[GaryM]

Thanks much!
Now I see I should put those code into a separate method.

Having 2 methods will work, but try this, first:

[your code is OK to here]
Transport.send(msg); // send using mail host 1
props.put("mail.smtp.host", hostNumber2 );
Transport.send(msg); // send using mail host 2

I am fairly sure it will work fine, but I can't test it in advance for
you at the moment

Gary