java - 如何使用 JavaMail 发送带有附件的 html 电子邮件

Question

以下 Java 代码用于将文件附加到 html 电子邮件并发送。我想用这封 html 电子邮件发送附件。如有任何建议，我们将不胜感激。

public void sendEmail(final String userName, final String password, final String host, final String html, final List<String> emails, String subject, String file) throws MessagingException
    {
        System.out.println("User Name: " + userName);
        System.out.println("Password: " + password);
        System.out.println("Host: " + host);

        //Get the session object  
        Properties props = new Properties();
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.auth", "true");

        Session session = Session.getDefaultInstance(props,
                new javax.mail.Authenticator()
                {
                    @Override
                    protected PasswordAuthentication getPasswordAuthentication()
                    {
                        return new PasswordAuthentication(userName, password);
                    }
                });

        if (!emails.isEmpty())
        {
            //Compose the message  
            InternetAddress[] address = new InternetAddress[emails.size()];
            for (int i = 0; i < emails.size(); i++)
            {
                address[i] = new InternetAddress(emails.get(i));
            }

            MimeMessage message = new MimeMessage(session);
            message.setFrom(new InternetAddress(userName));
            message.setRecipients(Message.RecipientType.TO, address);
            message.setSubject(subject);

            MimeBodyPart messageBodyPart = new MimeBodyPart();

            Multipart multipart = new MimeMultipart();

            messageBodyPart = new MimeBodyPart();
            String fileName = "attachmentName";
            DataSource source = new FileDataSource(file);
            messageBodyPart.setDataHandler(new DataHandler(source));
            messageBodyPart.setFileName(fileName);
            multipart.addBodyPart(messageBodyPart);
            message.setContent(html, "text/html; charset=utf-8");
            message.setContent(multipart);
            //send the message  
            Transport.send(message);

            System.out.println("message sent successfully...");
        } else
        {
            System.out.println("No Recieptions");
        }

    }

这给我带来的只是执着。但我想发送带有此附件的 html 电子邮件。

Answer 1

创建一个带有 HTML 正文和附件的邮件，实际上是创建一个内容为“多部分实体”的邮件，它包含两部分，一部分是 HTML 内容，另一部分是附件。

这与您当前的代码不符:

Multipart multipart = new MimeMultipart(); // creating a multipart is OK

// Creating the first body part of the multipart, it's OK
messageBodyPart = new MimeBodyPart();
// ... bla bla
// ok, so this body part is the "attachment file"
messageBodyPart.setDataHandler(new DataHandler(source));
// ... bla bla
multipart.addBodyPart(messageBodyPart); // at this point, the multipart contains your file attachment, but only that!

// at this point, you set your mail's body to be the HTML message    
message.setContent(html, "text/html; charset=utf-8");
// and then right after that, you **reset** your mail's content to be your multipart, which does not contain the HTML
message.setContent(multipart);

此时，您的电子邮件内容是一个多部分，只有一个部分，即您的附件。

因此，为了达到预期的结果，您应该采取不同的方式:

1. 创建一个多部分(就像您所做的那样)
2. 创建一个部分，将您的文件附件作为内容(就像您所做的那样)
3. 将这第一部分添加到多部分(就像您所做的那样)
4. 创建第二个 MimeBodyPart
5. 将您的 html 内容添加到第二部分
6. 将第二部分添加到您的多部分
7. 将电子邮件的内容设置为多部分(就像您所做的那样)

大致翻译为:

Multipart multipart = new MimeMultipart(); //1
// Create the attachment part
BodyPart attachmentBodyPart = new MimeBodyPart(); //2
attachmentBodyPart.setDataHandler(new DataHandler(fileDataSource)); //2
attachmentBodyPart.setFileName(file.getName()); // 2
multipart.addBodyPart(attachmentBodyPart); //3
// Create the HTML Part
BodyPart htmlBodyPart = new MimeBodyPart(); //4
htmlBodyPart.setContent(htmlMessageAsString , "text/html"); //5
multipart.addBodyPart(htmlBodyPart); // 6
// Set the Multipart's to be the email's content
message.setContent(multipart); //7