我希望将电子邮件保存为.eml格式并包含附件。我可以保存.eml文件，但当我打开它时，应该以草稿格式打开，用户应该能够输入发件人、收件人、主题和编辑电子邮件正文。目前我必须手动编辑已保存的.eml文件以添加X-Unsent:1以显示为草稿。如何在代码中实现此目标，哪个mimeMessage属性可以帮助我做到这一点？
public static void createMessage(String to, String from, String subject, String body, List<File> attachments) {
try {
Message message = new MimeMessage(Session.getInstance(System.getProperties()));
message.setFrom(new InternetAddress(from));
message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to));
message.setSubject(subject);
// create the message part
MimeBodyPart content = new MimeBodyPart();
// fill message
content.setText(body);
Multipart multipart = new MimeMultipart();
multipart.addBodyPart(content);
// add attachments
for(File file : attachments) {
MimeBodyPart attachment = new MimeBodyPart();
DataSource source = new FileDataSource(file);
attachment.setDataHandler(new DataHandler(source));
attachment.setFileName(file.getName());
multipart.addBodyPart(attachment);
}
// integration
message.setContent(multipart);
// store file
message.writeTo(new FileOutputStream(new File("c:/mail.eml")));
} catch (MessagingException ex) {
Logger.getLogger(Mailkit.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(Mailkit.class.getName()).log(Level.SEVERE, null, ex);
}
}