java - 如何从电子邮件中获取内联图像？

Question

我正在使用下一个代码使用 javamail API 从我的邮箱帐户下载附件和正文，它工作得很好。但是，当电子邮件中包含内联或嵌入图像时，图像不会以文本或附件文件的形式下载。我是 Java 的新手，一直在网上阅读，但没有找到易于理解的实现解决方案。有任何解决方法或代码来完成它吗？

这是我正在使用的代码:

public void processMessageBody(Message message) {
    try {
        Object content = message.getContent();
        // check for string
        // then check for multipart
        if (content instanceof String) {
            System.out.println(content);
        } else if (content instanceof Multipart) {
            Multipart multiPart = (Multipart) content;
            procesMultiPart(multiPart);
        } else if (content instanceof InputStream) {
            InputStream inStream = (InputStream) content;
            int ch;
            while ((ch = inStream.read()) != -1) {
                System.out.write(ch);
            }

        }

    } catch (IOException e) {
        e.printStackTrace();
    } catch (MessagingException e) {
        e.printStackTrace();
    }
}

public void procesMultiPart(Multipart content) {

    try {

        for (int i = 0; i < content.getCount(); i++) {
            BodyPart bodyPart = content.getBodyPart(i);
            Object o;

            o = bodyPart.getContent();
            if (o instanceof String) {
                System.out.println("Text = " + o);
            } else if (null != bodyPart.getDisposition()
                    && bodyPart.getDisposition().equalsIgnoreCase(
                            Part.ATTACHMENT)) {
                String fileName = bodyPart.getFileName();
                System.out.println("fileName = " + fileName);
                InputStream inStream = bodyPart.getInputStream();
                FileOutputStream outStream = new FileOutputStream(new File(
                        downloadDirectory + fileName));
                byte[] tempBuffer = new byte[4096];// 4 KB
                int numRead;
                while ((numRead = inStream.read(tempBuffer)) != -1) {
                    outStream.write(tempBuffer);
                }
                inStream.close();
                outStream.close();
            }
            // else?

        }
    } catch (IOException e) {
        e.printStackTrace();
    } catch (MessagingException e) {
        e.printStackTrace();
    }

}

我尝试添加下一个 if 语句以在它是内联图像时显示消息，但运气不佳:

 public void procesMultiPart(Multipart content) {

        try {

            for (int i = 0; i < content.getCount(); i++) {
                BodyPart bodyPart = content.getBodyPart(i);
                Object o;

                o = bodyPart.getContent();
// NOT WORKING
                if (o instanceof Image) {
                   System.out.println("procesMultiPart has Inline Images");
                } 
// 
else if (o instanceof String) {
                    System.out.println("Text = " + o);
                } else if (null != bodyPart.getDisposition()
                        && bodyPart.getDisposition().equalsIgnoreCase(
                                Part.ATTACHMENT)) {
                    String fileName = bodyPart.getFileName();
                    System.out.println("fileName = " + fileName);
                    InputStream inStream = bodyPart.getInputStream();
                    FileOutputStream outStream = new FileOutputStream(new File(
                            downloadDirectory + fileName));
                    byte[] tempBuffer = new byte[4096];// 4 KB
                    int numRead;
                    while ((numRead = inStream.read(tempBuffer)) != -1) {
                        outStream.write(tempBuffer);
                    }
                    inStream.close();
                    outStream.close();
                }
                // else?

            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (MessagingException e) {
            e.printStackTrace();
        }

    }

Answer 1

下面的代码应该适合你....

private String getAttachments(Message message, HttpServletRequest request) throws MessagingException, IOException {
String contentType = message.getContentType();
String attachFiles="";
if (contentType.contains("multipart")) {
    // content may contain attachments
    Multipart multiPart = (Multipart) message.getContent();
    int numberOfParts = multiPart.getCount();
    for (int partCount = 0; partCount < numberOfParts; partCount++) {
        MimeBodyPart part = (MimeBodyPart) multiPart.getBodyPart(partCount);
        String disposition =part.getDisposition();
        String file=part.getFileName();
        //External attachments
        if (disposition != null && Part.ATTACHMENT.equalsIgnoreCase(disposition)) {
            // this part is attachment
            String fileName = new Date().getTime()+ "_"+ part.getFileName().replaceAll("[^a-zA-Z0-9\\._]+", "_"); //To make attachment name uniq we are adding current datatime before name.
            attachFiles += fileName + ","; //concrete all attachment's name with comma separated.                  
            part.saveFile(new File(request
                    .getSession()
                    .getServletContext()
                    .getRealPath(
                            "/WEB-INF/attechments/"
                                    + fileName)));   //To save the attachment file at specific location.
    //                    LOG.info("\n\t Path :- " +request.getSession().getServletContext().getRealPath("/WEB-INF/attechments/" + fileName));
        }
        //Inline Attachments
        else if (disposition != null && Part.INLINE.equalsIgnoreCase(disposition)) {
            // this part is attachment
            String fileName = new Date().getTime()+ "_"+ part.getFileName().replaceAll("[^a-zA-Z0-9\\._]+", "_"); //To make attachment name uniq we are adding current datatime before name.
          //  attachFiles += fileName + ","; //concrete all attachment's name with comma separated.                  
            part.saveFile(new File(request
                    .getSession()
                    .getServletContext()
                    .getRealPath(
                            "/WEB-INF/attechments/"
                                    + fileName)));   //To save the attachment file at specific location.
//                    LOG.info("\n\t Path :- " +request.getSession().getServletContext().getRealPath("/WEB-INF/attechments/" + fileName));
        }
        //Inline icons and smileys
        else if(file != null && disposition==null)
        {
            String fileName = new Date().getTime()+ "_"+ part.getFileName().replaceAll("[^a-zA-Z0-9\\._]+", "_");
        //  attachFiles += fileName + ","; //concrete all attachment's name with comma separated.
             part.saveFile(new File(request
                    .getSession()
                    .getServletContext()
                    .getRealPath(
                            "/WEB-INF/attechments/"
                                    + fileName))); 

        }
    }
 }
 if (attachFiles.length() > 1) {
     attachFiles = attachFiles.substring(0, attachFiles.length() - 1);
 }
return attachFiles;
}