如何使用Javamail API读取eml文件中包含的eml文件

Question

我有一个EML文件，其中包含另一个EML文件作为附件。当我尝试使用JAVAMAIL API获取附件文件时，getDisposition值表示附件，而getfileName()显示NULL。

    Properties props = new Properties();
            Session mailSession = Session.getDefaultInstance(props, null);
            InputStream source = new FileInputStream("C:\\Mail1496085.eml");
            MimeMessage message = new MimeMessage(mailSession, source);
            System.out.println("Subject : " + message.getSubject());
            System.out.println("From : " + message.getFrom()[0]);
            System.out.println("--------------");
            System.out.println("Body : " +  message.getContent());
            String contentType = message.getContentType();
            if (contentType.contains("multipart")) {
System.out.println("Multipart EMail File");
            Multipart multiPart = (Multipart) message.getContent();
            int numberOfParts = multiPart.getCount();
            System.out.println("Parts:::"+numberOfParts);
            String wi="IM-67890-PROCESS";
            String saveDir = System.getProperty("user.dir")+"\\Docs";
            saveDir=saveDir + File.separator+wi;
            boolean file =new File(saveDir).mkdir();
           if (file) {
                  System.out.println("Directory: " + wi + " created");
                 // logger.debug("Directory: " + workItem + " created");
                }

            for (int partCount = 0; partCount < numberOfParts; partCount++) {
                MimeBodyPart part = (MimeBodyPart) multiPart.getBodyPart(partCount);
                String disposition=part.getDisposition();
                if (Part.ATTACHMENT.equalsIgnoreCase(disposition)) {
                    // this part is attachment      
                    String fileName = part.getFileName();
                    String extension="";
                    System.out.println("Attached File Name::"+fileName);
                    saveDir=saveDir + File.separator + fileName;
                    int i=fileName.lastIndexOf(".");
                        if(i>0)
                        {
                            extension=fileName.substring(i+1);
                        }
                     if(extension.equalsIgnoreCase("eml"))
                     {
                         part.saveFile(saveDir);
                         extractEML(saveDir, wi);
                         System.out.println("This is a eml file");
                     }
                     else if(extension.equalsIgnoreCase("msg"))
                     {
                         part.saveFile(saveDir);
                         extractMSG(saveDir,wi);
                         System.out.println("This is a msg file");
                     }
                     else
                     {
                         System.out.println("This is other file");
                     }
                   } else {
                        System.out.println("Not an eml file");
               System.out.println("File Name::"+part.getFileName());
                }
            }
        }
}


public static void extractEML(String emlPath,String wi) throws MessagingException, IOException
    {
        //String fileName=""; 
        String path=System.getProperty("user.dir") + File.separator + "Docs" + File.separator + wi + File.separator + "EML_PDF";
         boolean file =new File(path).mkdir();
         if(file)
         {
             System.out.println("Folder EML_PDF Created Successfully");
         }
        Properties props = new Properties();
        Session mailSession = Session.getDefaultInstance(props, null);
        InputStream source = new FileInputStream(emlPath);
        MimeMessage message = new MimeMessage(mailSession, source);
        System.out.println("Subject : " + message.getSubject());
        System.out.println("From : " + message.getFrom()[0]);
        System.out.println("--------------");
        System.out.println("Body : " +  message.getContent());
        String contentType = message.getContentType();
        if (contentType.contains("multipart")) {
            System.out.println("Multipart EMail File");
            Multipart multiPart = (Multipart) message.getContent();
            int numberOfParts = multiPart.getCount();
            System.out.println("Parts:::"+numberOfParts);
            for (int partCount = 0; partCount < numberOfParts; partCount++) {
                MimeBodyPart part = (MimeBodyPart) multiPart.getBodyPart(partCount);
                if (Part.ATTACHMENT.equalsIgnoreCase(part.getDisposition())) {
                     String fileName = part.getFileName();
                     String extension="";
                     path=path + File.separator + fileName;
                     int i=fileName.lastIndexOf(".");
                     if(i>0)
                     {
                        extension=fileName.substring(i+1);
                     }
                     if(extension.equalsIgnoreCase("pdf"))
                     {
                         part.saveFile(path);
                     }
                }
            }
        }
    }