使用 MultipartFile 发送带有多个附件的电子邮件答案

【问题标题】：email sending with multiple attachments using MultipartFile使用 MultipartFile 发送带有多个附件的电子邮件
【发布时间】：2021-04-24 20:00:12
【问题描述】：

我正在使用 MultipartFile 发送带有多个附件的电子邮件。我的代码工作正常，但我将每个文件存储在我的项目中，然后我正在附加。我不想将该文件存储在任何地方，而是希望将文件直接发送给收件人。我的代码是，

控制器：

@RequestMapping(value="/sendEmailAttachment",method=RequestMethod.POST)
public @ResponseBody Response sendEmail(@RequestParam("file") MultipartFile[] file,@ModelAttribute Email email) {
    SendEmail mail = new SendEmail();
    return mail.sendEmail(email,file);
}

服务：

public Response sendEmail(Email email,MultipartFile[] attachFiles) {
username = email.getUsername();
password = email.getPassword();
switch (email.getDomain()) {
case "1and1.com":
    host = "smtp.1and1.com";
    break;
case "gmail.com":
    host = "smtp.gmail.com";
    break;
case "yahoo.com":
    host = "smtp.mail.yahoo.com";
    break;
case "rediffmail.com":
    host = "smtp.rediffmail.com";
    break;
default:
    host = "smtp.1and1.com";
    username="support@gmail.com";
    password="************";
    break;
}
props.put("mail.smtp.host", host);
    Response response = new Response();

         Session session = Session.getInstance(props,
                  new javax.mail.Authenticator() {
                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication(username, password);
                    }
                  });
         try {
             // Create a default MimeMessage object.
             Message message = new MimeMessage(session);
             InternetAddress[] myToList = InternetAddress.parse(email.getTo());
                InternetAddress[] myBccList = InternetAddress.parse(email.getBcc());
                InternetAddress[] myCcList = InternetAddress.parse(email.getCc());
             // Set From: header field of the header.
             message.setFrom(new InternetAddress(email.getUsername()));

             // Set To: header field of the header.
             message.setRecipients(Message.RecipientType.TO,myToList);
                message.setRecipients(Message.RecipientType.BCC, myBccList);
                message.setRecipients(Message.RecipientType.CC, myCcList);

             // Set Subject: header field
             message.setSubject(email.getSubject());

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

             // Now set the actual message
             messageBodyPart.setContent(email.getBody(), "text/html");

             // Create a multipar message
             Multipart multipart = new MimeMultipart();

             // Set text message part
             multipart.addBodyPart(messageBodyPart);

             if(attachFiles != null && attachFiles.length > 0){
                    for (MultipartFile filePath : attachFiles) {
                        MimeBodyPart attachPart = new MimeBodyPart();
                        try {
                            filePath.transferTo(new File(filePath.getOriginalFilename()).getAbsoluteFile());
                            attachPart.attachFile(filePath.getOriginalFilename());
                        } catch (IOException ex) {
                            ex.printStackTrace();
                        }
                        multipart.addBodyPart(attachPart);
                    }
                }

             // Send the complete message parts
             message.setContent(multipart);
        //    Transport.send(message, message.getAllRecipients());
             Transport.send(message);

             response.setStatus(200);
             response.setMessage("Sent Email Successfully");

          } catch (MessagingException e) {
              response.setStatus(-1);
                response.setMessage(""+e);
                response.setObject(e);
                e.printStackTrace();
          }


        return response;

}

我在这里写过，

filePath.transferTo(new File(filePath.getOriginalFilename()).getAbsoluteFile());
                        attachPart.attachFile(filePath.getOriginalFilename());

我不想将文件传输/保存到项目中并附加，我想直接发送文件。任何帮助将不胜感激。

【问题讨论】：

标签： java spring jakarta-mail

【解决方案1】：

试试这个：

attachPart.setContent(filePath.getBytes(), filePath.getContentType());
attachPart.setFileName(filePath.getOriginalFilename());
attachPart.setDisposition(Part.ATTACHMENT);

【讨论】：

【解决方案2】：

就我而言，@Bill Shannon 的回答给了我错误"java.io.IOException: “text/plain” DataContentHandler requires String object, was given object of type class [B"

我修改了这样的代码：

DataSource ds = new ByteArrayDataSource(filePath.getBytes(), filePath.getContentType());
attachPart.setDataHandler(new DataHandler(ds));
attachPart.setFileName(filePath.getOriginalFilename());
attachPart.setDisposition(Part.ATTACHMENT);

【讨论】：

【解决方案3】：

如果你使用的是Spring，那么你可以使用JavaMailSenderImpl和MimeMessageHelper：

JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
MimeMessage mailMessage = mailSender.createMimeMessage();
MimeMessageHelper helper = new MimeMessageHelper(mailMessage, true);
helper.addAttachment("fileName", filePath);
mailSender.send(mailMessage);

【讨论】：