Question

我正在使用Javamail API，我正在尝试下载附件文件，例如word文件。问题是我在尝试读取字节并将其保存到文件时遇到base64解码异常。我正在使用以下代码。

Stack Exception：

IOException:com.sun.mail.util.DecodingException: BASE64Decoder: Error in encoded stream: needed 4 valid base64 characters but only got 2 before EOF, the 10 most recent characters were: "AG4AAAAAAA"

JavaMail代码：

 private void getAttachments(Message temp) throws IOException, MessagingException {
        List<File> attachments = new ArrayList<File>();

        Multipart multipart = (Multipart) temp.getContent();

        System.out.println(multipart.getCount());

        for (int i = 0; i < multipart.getCount(); i++) {
            BodyPart bodyPart = multipart.getBodyPart(i);
            if (!Part.ATTACHMENT.equalsIgnoreCase(bodyPart.getDisposition())) {
                continue; // dealing with attachments only
            }
            InputStream is = bodyPart.getInputStream();


            File f = new File("C:\\Attachments\\" + bodyPart.getFileName());

          //  saveFile(bodyPart.getFileName(),is);

            BufferedReader br = new BufferedReader(new InputStreamReader(is));

            while (br.ready()) {
                System.out.println(br.readLine());
            }



           saveFile(bodyPart.getFileName(),is);

            attachments.add(f);
        }



public static void saveFile(String filename,InputStream input) 
    {

        System.out.println(filename);
        try {
            if (filename == null) {
                //filename = File.createTempFile("VSX", ".out").getName();
                return;
            }
            // Do no overwrite existing file
            filename = "C:\\Attachments\\" + filename;
            File file = new File(filename);
            for (int i = 0; file.exists(); i++) {
                file = new File(filename + i);
            }
            FileOutputStream fos = new FileOutputStream(file);
            BufferedOutputStream bos = new BufferedOutputStream(fos);
            BufferedInputStream bis = new BufferedInputStream(input);


            int aByte;
            while ((aByte = bis.read()) >=0) {
                bos.write(aByte);
            }

            bos.flush();
            bos.close();
            bis.close();
        } // end of try()
        catch (IOException exp) {
            System.out.println("IOException:" + exp);
        }
    } //end of saveFile()

Answer 1

您需要禁用部分提取以解决此问题。这是你如何做到的

props.setProperty("mail.imap.partialfetch", "false");

或

props.setProperty("mail.imaps.partialfetch", "false");

如果你正在使用imaps。

以下是完整的参考： JavaMail BaseEncode64 Error

Answer 2

使用MimeBodyPart中的saveFile（）方法。如果你真的想在输入流中将自己的停止（！）读取行转移到你的saveFile方法之前。您正在消耗部分内容，这可能会导致问题。

使用Javamail从Gmail下载word文档

2 个答案: