java - 是否可以将内联位图对象添加到通过 JavaMail 发送的电子邮件正文中？

Question

我想将内联位图(在代码中生成)添加到要通过 Android 中的 JavaMail 发送的电子邮件中。以下是我当前的代码:

try {
            // Compose the message
            // javax.mail.internet.MimeMessage class is
            // mostly used for abstraction.
            Message message = new MimeMessage(session);

            // header field of the header.
            message.setFrom(new InternetAddress("service@someone.com"));

            message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(recipient));
            message.setSubject("Workside Verification Service");
            message.setText(
                    "Thank you for registering. Please click on the following link to activate your account:\n\n"
                            + urlWithToken
                            + "\n\nRegards,\nThe Workside Team");

            // Add the generated QR code bitmap here
            Multipart multipart = new MimeMultipart("related");
            MimeBodyPart imgPart = new MimeBodyPart();
            // imageFile is the file containing the image

            // TODO - pass bitmap to imageFile below
            File file = new File(null);
            OutputStream os = new BufferedOutputStream(new FileOutputStream(file));

            mBitmapQR.compress(Bitmap.CompressFormat.PNG, 90, os);


            imgPart.attachFile(imageFile);
            multipart.addBodyPart(imgPart);
            message.setContent(multipart);

            Transport.send(message); // send Message

            System.out.println("Email Sent");

        } catch (MessagingException | FileNotFoundException e) {
            throw new RuntimeException(e);
        }

我正在考虑将位图转换为 File 对象，然后将其添加到消息正文中，但我认为可能有一种更直接、更有效的方法。

Answer 1

Jakarta 邮件常见问题解答是您最好的资源。请参阅How do I send HTML mail that includes images? 。这描述了 3 个选择:

1. 将图像链接到网站，我怀疑这是否适合您。
2. 内联图像 <img src="data:image/jpeg;base64,base64-encoded-data-here" />
3. 像您正在做的那样构建多部分/相关消息。