Problem with subject encoding when sending an email

问题

I'm sending an email and I'm receiving it correctly but the encoding of the subject is not correct. I'm sending "invitación" but I'm receiving "invitaci?n". The content of the message is OK.

The content of the message is coming from a transformation of a Velocity Template while the subject is set in a String variable.

I've googled around and I've seen that some people says that MimeUtility.encodeText() could solve the problem, but I have had no success with it.

How can I solve the problem? This is the code I have so far.

String subject = "Invitación";
String msgBody = VelocityEngineUtils.mergeTemplateIntoString(velocityEngine, "/vmTemplates/template.vm", "UTF-8", model);

Properties props = new Properties();
Session session = Session.getDefaultInstance(props, null);

try {
    String encodingOptions = "text/html; charset=UTF-8";
    Message msg = new MimeMessage(session);
    msg.setHeader("Content-Type", encodingOptions);
    msg.setFrom(new javax.mail.internet.InternetAddress(emailFrom));
    msg.addRecipient(Message.RecipientType.TO, new InternetAddress(emailTo));

    msg.setSubject(subject);
    msg.setContent(msgBody, encodingOptions);
    Transport.send(msg);

    } catch (AddressException e) {
        ...
    } catch (MessagingException e) {
        ...
    }

Thanks

回答1:

JavaMail has perhaps a little too much abstraction, and you're falling victim to it here. When you use

Message msg = new MimeMessage(session);

you're creating a MimeMessage object but treating it as a Message object. Message has only a setSubject(String subject) method, which uses the platform default charset to encode the subject. If the platform default can't encode it, you get ? characters in the resulting header. MimeMessage, however, has a setSubject(String subject, String charset) method which will allow you to specify the charset you want to use to encode the subject. So just switch your code to

MimeMessage msg = new MimeMessage(session);
msg.setHeader("Content-Type", encodingOptions);
msg.setFrom(new javax.mail.internet.InternetAddress(emailFrom));
msg.addRecipient(Message.RecipientType.TO, new InternetAddress(emailTo));

msg.setSubject(subject, "UTF-8");

and it should work.

回答2:

you can use, it works

msg.setSubject(MimeUtility.encodeText("string", "UTF-8", "Q"));

回答3:

Maybe you can try: msg.setSubject(subject, "UTF8");

回答4:

In my case the only thing which worked is changing the system locale to the one which supports desired character set. Before that I tried many different ways including the accepted answer from this thread, but none of them helped.

来源：https://stackoverflow.com/questions/4897836/problem-with-subject-encoding-when-sending-an-email

标签

java

google-app-engine

encoding

javamail

velocity