JavaMail MimeBodyPart。SaveFile提供损坏的文件

Question

我正在使用JavaMail库解析电子邮件mime消息。我正在尝试提取附件并将其保存到本地磁盘，但保存的文件无效，并且大小与原始文件不同。只有*。txt文件保存正常，但*。PDF或*。xlsx不是。你能帮我修一下密码吗？

我的代码是：

private static void Test3() {
        String email_string = File_Reader.Read_File_To_String("D:\\8.txt");
        MimeMessage mm = Email_Parser.Get_MIME_Message_From_Email_String(email_string);

        Email_Parser.Save_Email_Attachments_To_Folder(mm,"D:\\TEST");
    }

public static String Read_File_To_String(String file_path) {
    byte[] encoded = new byte[0];

    try {
        encoded = Files.readAllBytes(Paths.get(file_path));
    } catch (IOException exception) {
        Print_To_Console(exception.getMessage(), true,false);
    }

    return new String(encoded, m_encoding);
}

public static MimeMessage Get_MIME_Message_From_Email_String(String email_string) {
    MimeMessage mm = null;

    try {
        Session s = Session.getDefaultInstance(new Properties());
        InputStream is = new ByteArrayInputStream(email_string.getBytes());
        mm = new MimeMessage(s, is);
    } catch (MessagingException exception) {
        Print_To_Console(exception.getMessage(), true, false);
    }
    return mm;
}

public static void Save_Email_Attachments_To_Folder(MimeMessage mm, String output_folder_path) {
        ArrayList<Pair<String, InputStream>> attachments_InputStreams = Get_Attachments_InputStream_From_MimeMessage(mm);
        String attachment_filename;
        String attachment_filename_save_path;
        InputStream attachment_InputStream;
        MimeBodyPart mbp;

        for (Pair<String, InputStream> attachments_InputStream : attachments_InputStreams) {
            attachment_filename = attachments_InputStream.getKey();
            attachment_filename = Get_Encoded_String(attachment_filename);
            attachment_filename_save_path = String.format("%s\\%s", output_folder_path, attachment_filename);
            attachment_InputStream = attachments_InputStream.getValue();

            try {
                mbp = new MimeBodyPart(attachment_InputStream);
                mbp.saveFile(attachment_filename_save_path);
            } catch (MessagingException | IOException exception) {
                Print_To_Console(exception.getMessage(), true, false);
            }
        }
    }

Answer 1

你在Save_Email_Attachments_To_文件夹中做了一些非常奇怪的事情。（更不用说使用驼峰大小写和下划线的奇怪命名约定了。：-）我不知道您正在收集的InputStreams是什么，但基于它们构建新的MimeBodyPart，然后使用新的MimeBodyPart将附件保存到文件中几乎肯定不是您想要做的事情。

从MimeMessage获取附件输入流到底在做什么？为什么要迭代消息以收集一组输入流，然后迭代输入流以保存它们？为什么不在邮件上迭代以查找附件，并在使用MimeBodyPart查找附件时保存它们呢。保存文件方法？你看过msgshow吗。java示例程序？