JavaMailSender写入多部分异常

Question

当我使用JavaMailSender发送带有附件的电子邮件时，它总是失败，并引发以下异常：

org.springframework.mail.MailSendException: Failed messages: javax.mail.MessagingException: IOException while sending message;
  nested exception is:
    java.io.IOException: Exception writing Multipart
; message exception details (1) are:
Failed message 1:
javax.mail.MessagingException: IOException while sending message;
  nested exception is:
    java.io.IOException: Exception writing Multipart
    at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1365)
    at org.springframework.mail.javamail.JavaMailSenderImpl.doSend(JavaMailSenderImpl.java:462)
    at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:359)
    at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:354)

这是我的密码

MimeMessage message = mailSender.createMimeMessage();
try {
    MimeMessageHelper helper = new MimeMessageHelper(message, true);
    helper.setFrom(userName);
    helper.setTo(toAddress);
    helper.setSubject(subject);
    FileSystemResource file = new FileSystemResource(filePath);
    helper.addAttachment(file.getFilename(), file);
} catch (Exception e) {
    log.error("oops..., ", e);
}
mailSender.send(message);

Answer 1

如果不设置文本，则会出现此错误。即使设置为空字符串，也需要设置文本。

https://stackoverflow.com/a/33015901/9905202

Answer 2

设置内容类型，我通过将内容类型设置为第三个参数来解决这个问题

帮手addAttachment（“附件文件名”，新的ByteArrayResource（IOUtils.toByteArray（inputStream）），“application/pdf”）；

Answer 3

我幸运地解决了这个问题。

只需在附件中设置一个空文本内容，就像这样就可以了。

helper.addAttachment(MimeUtility.encodeText("")), new ByteArrayResource(IOUtils.toByteArray(inputStream)));
helper.setText("", true);