在android中使用java发送邮件时出错（带附件）

Question

我正在尝试通过 java 在 android 中（在 AsyncTask 中）发送带有附件的邮件，我有这个方法：

 Properties props = new Properties();
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");

        Session session = Session.getInstance(props, new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication("[email protected]", "psw");
            }
        });

        Message message = new MimeMessage(session);
        try {
            message.setFrom(new InternetAddress("[email protected]@gmail.com"));
            message.setRecipients(Message.RecipientType.TO, InternetAddress.parse("[email protected]"));
            message.setSubject("Subject line");
            message.setText("Email content");

            MimeBodyPart messageBodyPart = new MimeBodyPart();
            messageBodyPart.setText("test");

            MimeBodyPart attachmentBodyPart = new MimeBodyPart();
            DataSource source = new FileDataSource(fileName);
            attachmentBodyPart.setDataHandler(new DataHandler(source));
            attachmentBodyPart.setFileName(source.getName());

            MimeMultipart multipart = new MimeMultipart();
            multipart.addBodyPart(messageBodyPart);
            multipart.addBodyPart(attachmentBodyPart);
            message.setContent(multipart);

            Transport.send(message);


        } catch (MessagingException ex) {
            throw new RuntimeException(ex);
        }

在文件名上我保存了文件名

FileOutputStream outputStream = context.openFileOutput(nameExelFile, Context.MODE_PRIVATE);

我得到的错误是：

E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
    Process: com.gattolfo.gestionaluber, PID: 6179
    java.lang.RuntimeException: An error occurred while executing doInBackground()
        at android.os.AsyncTask$4.done(AsyncTask.java:415)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:383)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:252)
        at java.util.concurrent.FutureTask.run(FutureTask.java:271)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:305)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:923)
     Caused by: java.lang.RuntimeException: javax.mail.MessagingException: IOException while sending message;
      nested exception is:
        javax.activation.UnsupportedDataTypeException: no object DCH for MIME type multipart/mixed; 
        boundary="----=_Part_0_82827468.1680314088984"
        at com.gattolfo.gestionaluber.DataManager.DbRappresentation.Registri.MailSender.sendMailInstant(MailSender.java:296)
        at com.gattolfo.gestionaluber.DataManager.DbRappresentation.Registri.MailSender.doInBackground(MailSender.java:141)
        at com.gattolfo.gestionaluber.DataManager.DbRappresentation.Registri.MailSender.doInBackground(MailSender.java:48)
        at android.os.AsyncTask$3.call(AsyncTask.java:394)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
            ... 4 more
     Caused by: javax.mail.MessagingException: IOException while sending message;
      nested exception is:
        javax.activation.UnsupportedDataTypeException: no object DCH for MIME type multipart/mixed; 
        boundary="----=_Part_0_82827468.1680314088984"
        at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1350)
        at javax.mail.Transport.send0(Transport.java:231)
        at javax.mail.Transport.send(Transport.java:100)
        at com.gattolfo.gestionaluber.DataManager.DbRappresentation.Registri.MailSender.sendMailInstant(MailSender.java:292)
            ... 8 more
     Caused by: javax.activation.UnsupportedDataTypeException: no object DCH for MIME type multipart/mixed; 
        boundary="----=_Part_0_82827468.1680314088984"
        at javax.activation.ObjectDataContentHandler.writeTo(DataHandler.java:878)
        at javax.activation.DataHandler.writeTo(DataHandler.java:300)
        at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1670)
        at javax.mail.internet.MimeMessage.writeTo(MimeMessage.java:1889)
        at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1300)
            ... 11 more

我在用

    implementation 'com.sun.mail:android-mail:1.6.7'
    implementation 'com.sun.mail:android-activation:1.6.7'

我也试过：

implementation 'com.sun.mail:jakarta.mail:2.0.1'

请帮忙!!

我的电脑（windows java）上的相同代码工作正常，我认为问题出在android内存的输入/输出

[编辑]

我注意到添加这样的附件：

MimeBodyPart messageBodyPart = new MimeBodyPart();
           String jsonContent = "{\"name\": \"John Doe\", \"email\": \"[email protected]\"}";
           messageBodyPart.setContent(jsonContent, "application/json");

从完全相同的错误，它不会给出错误的唯一方法是如果我不添加这样的附件：

 MimeMessage message = new MimeMessage(session);
           message.setFrom(new InternetAddress(username));
           message.addRecipient(Message.RecipientType.TO, new InternetAddress(mailReciver));
           message.setSubject("Report utilizzo cassette");
           message.setText("message");
           Transport.send(message);