以 PDF 附件作为流发送电子邮件

我想将 Pdf 作为电子邮件附件发送（我正在使用 JavaMail API）。我有 Pdf（由 jasper 生成）作为byte[].

public InputStream exportPdfToInputStream(User user) throws ParseErrorException, MethodInvocationException, ResourceNotFoundException, JRException, IOException{
        JasperPrint jasperPrint = createJasperPrintObject(user);
        byte[] pdfByteArray = JasperExportManager.exportReportToPdf(jasperPrint);
        return new ByteArrayInputStream(pdfByteArray);
    }

这是我用来构建的代码MimeBodyPart这将是附件：

    if (arrayInputStream != null && arrayInputStream instanceof ByteArrayInputStream) {
        MimeBodyPart attachment = new MimeBodyPart(arrayInputStream);
        attachment.setHeader("Content-Type", "application/pdf");
        mimeMultipart.addBodyPart(attachment);
    }

这段代码给了我这个错误：

javax.mail.MessagingException: IOException while sending message;
  nested exception is:
    java.io.IOException: Error in encoded stream: needed at least 2 valid base64 characters, but only got 1 before padding character (=), the 10 most recent characters were: "\24\163\193\n\185\194\216#\208="

我已经找到了建议的解决方案this线。似乎有一个DataSource专门为此目的创建的类。希望这个例子对其他人也有帮助。

    if (arrayInputStream != null && arrayInputStream instanceof ByteArrayInputStream) {
        // create the second message part with the attachment from a OutputStrean
        MimeBodyPart attachment= new MimeBodyPart();
        ByteArrayDataSource ds = new ByteArrayDataSource(arrayInputStream, "application/pdf"); 
        attachment.setDataHandler(new DataHandler(ds));
        attachment.setFileName("Report.pdf");
        mimeMultipart.addBodyPart(attachment);
    }