带有包含图像的HTML主体的日历邀请

尝试使用下面的代码，其中包含一个方法来附加内联图像以及电子邮件邀请和正常附件，只需根据您的需要调整代码

private String senderAddress = "YOUR EMAIL ADDRESS";
    private final String password = "YOUR EMAIL PASSWORD";
    public static SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMdd'T'HHmm'00'");
    public static SimpleDateFormat dateParser = new SimpleDateFormat("dd-MM-yyyy HH:mm");
    public static SimpleDateFormat dateFormater = new SimpleDateFormat("dd-MM-yyyy");
    public String getSenderAddress() {
        return senderAddress;
    }
    public String getPassword() {
        return password;
    }
    public Session getMailSession() {
        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");
        return Session.getInstance(props, new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(getSenderAddress(), getPassword());
            }
        });
    }
    public String newSend(Invitation invitation, String methodType)  {
        String UID = null;
        // register the text/calendar mime type
        MimetypesFileTypeMap mimetypes = (MimetypesFileTypeMap) MimetypesFileTypeMap.getDefaultFileTypeMap();
        mimetypes.addMimeTypes("text/calendar ics ICS");
        // register the handling of text/calendar mime type
        MailcapCommandMap mailcap = (MailcapCommandMap) MailcapCommandMap.getDefaultCommandMap();
        mailcap.addMailcap("text/calendar;; x-java-content-handler=com.sun.mail.handlers.text_plain");
        MimeMessage message = new MimeMessage(getMailSession());
        try {
            message.setFrom(new InternetAddress(senderAddress));
            message.setSubject(invitation.getSubject());
            message.addRecipient(Message.RecipientType.TO, new InternetAddress(invitation.getTo()));
            Multipart multipart = new MimeMultipart("mixed");
            invitation.setDescription(getHtmlWithEncodedImages(multipart,invitation));
            Multipart mpMixedAlternative = newChild(multipart, "alternative");
            // html part
            BodyPart messageBodyPart = buildHtmlTextPart(invitation);
            mpMixedAlternative.addBodyPart(messageBodyPart);
            // Add part two, the calendar
            BodyPart calendarPart = buildCalendarPart(invitation, methodType);
            calendarPart.setDisposition(BodyPart.INLINE);
            mpMixedAlternative.addBodyPart(calendarPart);
            addAttachment(multipart);
            // Put the multipart in message
            message.setContent(multipart);
            // send the message
            Transport transport = getMailSession().getTransport("smtp");
            transport.connect();

            transport.sendMessage(message, message.getAllRecipients());
            transport.close();
            UID = invitation.getTo() + "" + invitation.getStartdate().toString() + "" + invitation.getStarttime();
        } catch (Exception e) {
            //TODO logger log exception
        }
        return UID;
    }
    private void addAttachment(Multipart multipart) {
        MimeBodyPart mbpAttachment = new MimeBodyPart();
        File file=new File("C:/users/ishan.juneja/Desktop/temp.txt");
        DataSource datasource=new FileDataSource(file);
        try {
            mbpAttachment.setDataHandler(new DataHandler(datasource));
            mbpAttachment.setDisposition(BodyPart.ATTACHMENT);
            mbpAttachment.setFileName("temp.txt");
            multipart.addBodyPart(mbpAttachment);
        } catch (MessagingException e) {
            // TODO logger log exception
        }

    }
    public String uploadImage(MultipartFile file){
        byte[] bytes;
        try {
            String path = System.getProperty("catalina.home");
            File dir = new File(path+"/tmpFiles");
            if(!dir.isDirectory()){
                dir.mkdir();
                }
            bytes = file.getBytes();
            File serverfile = new File(dir.getAbsolutePath()+"/"+file.getName()+Math.random()+".png");
            BufferedOutputStream stream = new BufferedOutputStream(new FileOutputStream(serverfile));
            stream.write(bytes);
            stream.close();
            System.out.println("file uploaded "+serverfile.getAbsolutePath());
            String hostname="Unknown";
            try {
                hostname = InetAddress.getLocalHost().getHostName();
            } catch (UnknownHostException e1) {
                e1.printStackTrace();
            }

            return "{'"location'" : '"http://"+hostname+":8080/emailinvitation/image/path/"+serverfile.getName()+"'"}";
        } catch (IOException e) {
        }
        return "{'"location'":'"http://localhost:8080/emailinvitation/image/path/unknown.png'"}";
    }
    private Multipart newChild(Multipart parent, String alternative) {
        MimeMultipart child = new MimeMultipart(alternative);
        MimeBodyPart mbp = new MimeBodyPart();
        try {
            parent.addBodyPart(mbp);
            mbp.setContent(child);
        } catch (MessagingException e) {
            // TODO logger log exception
        }
        return child;
    }
    private BodyPart buildCalendarPart(Invitation invitation, String methodType) throws Exception {
        Date date1 = dateParser.parse(dateFormater.format(invitation.getStartdate()) + " " + invitation.getStarttime());
        String startDate = timeZoneToUTC(invitation, date1);
        Date date2 = dateParser.parse(dateFormater.format(invitation.getEnddate()) + " " + invitation.getEndtime());
        String endDate = timeZoneToUTC(invitation, date2);
        BodyPart calendarPart = new MimeBodyPart();

        String calendarContent = "BEGIN:VCALENDAR'n" + "METHOD:" + methodType + "'n" + "PRODID: BCP - Meeting'n"
                + "VERSION:2.0'n" + "X-WR-TIMEZONE:" + invitation.getTimezone() + "'n" + "BEGIN:VEVENT'n" + "DTSTAMP:"
                + startDate + "Z'n" + "DTSTART:" + startDate + "Z'n" + "DTEND:" + endDate + "Z'n"
                + "SUMMARY:test request'n" + "UID:" + invitation.getTo() + "" + startDate + "'n"
                + "ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=FALSE:MAILTO:" + invitation.getTo() + "'n"
                + "ORGANIZER:MAILTO:" + senderAddress + "'n" + "LOCATION:Test'n"  + "SEQUENCE:0'n"
                + "PRIORITY:5'n" + "CLASS:PUBLIC'n" + "STATUS:CONFIRMED'n" + "TRANSP:OPAQUE'n" + "BEGIN:VALARM'n"
                + "ACTION:DISPLAY'n" + "DESCRIPTION:REMINDER'n" + "TRIGGER;RELATED=START:-PT00H15M00S'n"
                + "END:VALARM'n" + "END:VEVENT'n" + "END:VCALENDAR";
        calendarPart.addHeader("Content-Class", "urn:content-classes:calendarmessage");
        calendarPart.setContent(calendarContent, "text/calendar;method=" + methodType);
        return calendarPart;
    }
    private BodyPart buildHtmlTextPart(Invitation invitation) {
        MimeBodyPart descriptionPart = new MimeBodyPart();
        String content = invitation.getDescription();
        try {
            descriptionPart.setContent(content, "text/html; charset=utf-8");
        } catch (MessagingException e) {
            // TODO logger log exception
        }
        return descriptionPart;
    }
    private void addImages(Multipart parent,String filename)  {
        MimeBodyPart mbpAttachment = new MimeBodyPart();
        try {
            File file = new File("C:''apache-tomcat-8.5.24''tmpFiles''"+filename);
            FileDataSource ds = new FileDataSource(file);
            mbpAttachment.setDataHandler(new DataHandler(ds));
            mbpAttachment.setDisposition(BodyPart.INLINE);
            mbpAttachment.setHeader("Content-ID", filename);
            mbpAttachment.setFileName(filename);
            parent.addBodyPart(mbpAttachment);
        } catch (Exception e) {
            //TODO logger log exception
        }

    }
    private String timeZoneToUTC(Invitation invitation, Date date) {
        ZoneId zone = ZoneId.of(invitation.getTimezone());
        String date1 = dateParser.format(date);
        DateTimeFormatter fmt = DateTimeFormatter.ofPattern("dd-MM-yyyy HH:mm").withZone(zone);
        ZonedDateTime utc = ZonedDateTime.parse(date1, fmt).withZoneSameInstant(ZoneId.of("UTC"));
        Timestamp sqlTs = Timestamp.valueOf(utc.toLocalDateTime());
        return dateFormat.format(sqlTs);
    }
    public String getHtmlWithEncodedImages(Multipart parent,Invitation invitation) {
        String temp = invitation.getDescription();
        String html="<html><body>"+invitation.getDescription()+"</body></html>";
        Document document = Jsoup.parse(html);
        Elements allElements=document.body().getElementsByTag("img");
        for (Element element : allElements) {
            String elementstring=element.toString();
            String tempfilename = elementstring.substring(elementstring.indexOf("file"));
            String filename=tempfilename.substring(0,tempfilename.indexOf('"'));
            temp=temp.replace(elementstring.substring(elementstring.indexOf('"'), elementstring.lastIndexOf('"')),"'"cid:"+filename);
            addImages(parent, filename);
        }
        System.out.println("--++--"+temp);
        return temp;
    }