java - 在 java 中发送消息时出现 MessagingException IOException？

Question

我使用以下代码发送邮件。短信发送工作正常，但带附件的邮件不工作，它给出了异常。如何解决这个问题

javax.mail.MessagingException: IOException while sending message; nested exception is: javax.activation.UnsupportedDataTypeException: no object DCH for MIME type multipart/mixed; boundary="----=_Part_0_10430987.1294298904906" at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:676) at javax.mail.Transport.send0(Transport.java:189) at javax.mail.Transport.send(Transport.java:118) at Gmailer.GMailSender.sendMailAttach(GMailSender.java:114) at SendMail.main(SendMail.java:22) Caused by: javax.activation.UnsupportedDataTypeException: no object DCH for MIME type multipart/mixed; boundary="----=_Part_0_10430987.1294298904906" at javax.activation.ObjectDataContentHandler.writeTo(Unknown Source) at javax.activation.DataHandler.writeTo(Unknown Source) at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1403) at javax.mail.internet.MimeMessage.writeTo(MimeMessage.java:1745) at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:636) ... 4 more

带有附件代码的邮件:

public synchronized void sendMailAttach(String subject, String body,
    String sender, String recipients)  {
try {
    MimeMessage message = new MimeMessage(session);

    message.setSender(new InternetAddress(sender));
    message.setSubject(subject);

    // Create the message part 
    BodyPart messageBodyPart = new MimeBodyPart();

    // Fill the message
    messageBodyPart.setText("hi Demo");

    Multipart multipart = new MimeMultipart();
    multipart.addBodyPart(messageBodyPart);

    // Part two is attachment
    messageBodyPart = new MimeBodyPart();
    String filename = "mail.txt";
    DataSource source = new FileDataSource(filename);
    messageBodyPart.setDataHandler(new DataHandler(source));
    messageBodyPart.setFileName(filename);
    multipart.addBodyPart(messageBodyPart);

    // Put parts in message
    message.setContent(multipart);

    if (recipients.indexOf(',') > 0)
        message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse(recipients));
    else
        message.setRecipient(Message.RecipientType.TO,
                new InternetAddress(recipients));
    Transport.send(message);

}
catch (MessagingException e) {
    System.out.println("MessagingException" + e.getMessage());
}
catch (Exception e) {
    System.out.println("Mail Send Exception " + e.getMessage());
}
 }

短信发送代码:

public synchronized void sendMail(String subject, String body,
    String sender, String recipients) throws Exception {
try {
    MimeMessage message = new MimeMessage(session);
    DataHandler handler = new DataHandler(new ByteArrayDataSource(
            body.getBytes(), "text/plain"));
    message.setSender(new InternetAddress(sender));
    message.setSubject(subject);
    message.setDataHandler(handler);
    if (recipients.indexOf(',') > 0)
        message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse(recipients));
    else
        message.setRecipient(Message.RecipientType.TO,
                new InternetAddress(recipients));
    Transport.send(message);
} catch (Exception e) {

}
}

Answer 1

首先，您可以通过使用 MimeBodyPart.attachFile() 而不是争论 DataSource/DataHandler 代码使您的代码更简洁自己。

其次，尝试为附件部分的 Content-Type 和 Content-Disposition header 设置适当的值。 (attachFile 将默认为您设置 Content-Disposition。)例如，

messageBodyPart = new MimeBodyPart();
messageBodyPart.attachFile(new File("mail.txt"));
messageBodyPart.setHeader("Content-Type", "text/plain; charset=\"us-ascii\"; name=\"mail.txt\"");

---

编辑:

想了想，这一定是类加载出了问题。请查看this other SO thread看看它是否可以解决您的情况。 (一般问题:可能是您的类路径中有一个额外的 activation.jar；其他一些可能性也被认为是导致它的原因。)