如何创建pdf文件并发送Spring boot应用程序的邮件

Question

我正在尝试发送电子邮件，附件是创建的pdf文档，我工作的环境是基于REST的java spring boot应用程序，

实际上，我知道如何使用thymeleaf模板引擎发送电子邮件，但如何在内存中创建pdf文档，并将其作为附件发送，这是我用于发送电子邮件的代码。

Context cxt = new Context();
cxt.setVariable("doctorFullName", doctorFullName);
String message = templateEngine.process(mailTemplate, cxt);
emailService.sendMail(MAIL_FROM, TO_EMAIL,"Subject", "message");

这是sendmail（）函数

 @Override
    public void sendPdfMail(String fromEmail, String recipientMailId, String subject, String body) {
        logger.info("--in the function of sendMail");
        final MimeMessage mimeMessage = this.mailSender.createMimeMessage();
        try {
            final MimeMessageHelper message = new MimeMessageHelper(mimeMessage, true, "UTF-8");
            message.setSubject(subject);
            message.setFrom(fromEmail);
            message.setTo(recipientMailId);
            message.setText(body, true);

            FileSystemResource file = new FileSystemResource("C:\\xampp\\htdocs\\project-name\\logs\\health360-logging.log");
            message.addAttachment(file.getFilename(), file);


            this.mailSender.send(mimeMessage);
            logger.info("--Mail Sent Successfully");
        } catch (MessagingException e) {
            logger.info("--Mail Sent failed ---> " + e.getMessage());
            throw new RuntimeException(e.getMessage());
        }
    }

实际上我需要创建一种2-3页的报告作为pdf文件，并通过邮件发送。

我还需要发送多个pdf报告，在邮件中，我该怎么做，你的朋友们能帮我吗，我找到了一个叫做jasper的东西，它和我的环境有关吗，

Answer 1

这是您发送邮件的方式：

public void email() {
    String smtpHost = "yourhost.com"; //replace this with a valid host
    int smtpPort = 587; //replace this with a valid port

    String sender = "[e-mail]"; //replace this with a valid sender email address
    String recipient = "[e-mail]"; //replace this with a valid recipient email address
    String content = "dummy content"; //this will be the text of the email
    String subject = "dummy subject"; //this will be the subject of the email

    Properties properties = new Properties();
    properties.put("mail.smtp.host", smtpHost);
    properties.put("mail.smtp.port", smtpPort);     
    Session session = Session.getDefaultInstance(properties, null);

    ByteArrayOutputStream outputStream = null;

    try {           
        //construct the text body part
        MimeBodyPart textBodyPart = new MimeBodyPart();
        textBodyPart.setText(content);

        //now write the PDF content to the output stream
        outputStream = new ByteArrayOutputStream();
        writePdf(outputStream);
        byte[] bytes = outputStream.toByteArray();

        //construct the pdf body part
        DataSource dataSource = new ByteArrayDataSource(bytes, "application/pdf");
        MimeBodyPart pdfBodyPart = new MimeBodyPart();
        pdfBodyPart.setDataHandler(new DataHandler(dataSource));
        pdfBodyPart.setFileName("test.pdf");

        //construct the mime multi part
        MimeMultipart mimeMultipart = new MimeMultipart();
        mimeMultipart.addBodyPart(textBodyPart);
        mimeMultipart.addBodyPart(pdfBodyPart);

        //create the sender/recipient addresses
        InternetAddress iaSender = new InternetAddress(sender);
        InternetAddress iaRecipient = new InternetAddress(recipient);

        //construct the mime message
        MimeMessage mimeMessage = new MimeMessage(session);
        mimeMessage.setSender(iaSender);
        mimeMessage.setSubject(subject);
        mimeMessage.setRecipient(Message.RecipientType.TO, iaRecipient);
        mimeMessage.setContent(mimeMultipart);

        //send off the email
        Transport.send(mimeMessage);

        System.out.println("sent from " + sender + 
                ", to " + recipient + 
                "; server = " + smtpHost + ", port = " + smtpPort);         
    } catch(Exception ex) {
        ex.printStackTrace();
    } finally {
        //clean off
        if(null != outputStream) {
            try { outputStream.close(); outputStream = null; }
            catch(Exception ex) { }
        }
    }
}

您可以看到我们创建了一个MimeBodyPart，其中包含从bytes创建的DataSource，该方法由名为WritePdf（）的方法产生：

public void writePdf(OutputStream outputStream) throws Exception {
    Document document = new Document();
    PdfWriter.getInstance(document, outputStream);
    document.open();
    Paragraph paragraph = new Paragraph();
    paragraph.add(new Chunk("hello!"));
    document.add(paragraph);
    document.close();
}

因为我们使用字节输出流而不是文件输出流所以没有文件被写入磁盘。