通过java mail发送带有包含字节[]的附件的电子邮件

Question

0x255044462D312E330A25AAABAC

• 在查看代码之前，请阅读此处:

当我发送bytes（返回getPDFByteStream()方法）时，它会像原始文件一样在电子邮件中发送附件。但当我从数据库中获取并发送时，它会发送损坏的文件。

更新：

@Lob
@Column(name = "ATTACHED_FILE")
private byte[] attachedFile;

//getter()/setter();

 try {
        MimeBodyPart textBodyPart = new MimeBodyPart();
        textBodyPart.setText(content);

       //byte[] bytes = getPDFByteStream(); //Returns byte[] reading local drive file


         **UPDATE:**

        //bytes[] bytes=entity.getAttachedFile(); // It gets value from entity.

        /**
        ** It is getting like "[B@7ffd10fa" format but m storing on database like "0x255044462D312E330A25" format
        **/

        String string="0x255044462D312E330A25";
        byte[] bytes =string.getBytes(Charset.forName("UTF-8"));
        System.out.println("bytes " + bytes.toString());

        DataSource dataSource = new ByteArrayDataSource(bytes, "application/pdf");
        MimeBodyPart pdfBodyPart = new MimeBodyPart();
        pdfBodyPart.setDataHandler(new DataHandler(dataSource));
        pdfBodyPart.setFileName("bankAdminReport.pdf");

        MimeMultipart mimeMultipart = new MimeMultipart();
        mimeMultipart.addBodyPart(textBodyPart);
        mimeMultipart.addBodyPart(pdfBodyPart);

        InternetAddress iaSender = new InternetAddress(sender);
        InternetAddress iaRecipient = new InternetAddress(recipient);

        MimeMessage mimeMessage = new MimeMessage(session);
        mimeMessage.setSender(iaSender);
        mimeMessage.setSubject(subject);
        mimeMessage.setRecipient(Message.RecipientType.TO, iaRecipient);
        mimeMessage.setContent(mimeMultipart);

        Transport.send(mimeMessage);
    } catch (Exception ex) {
        ex.printStackTrace();
    }

public static byte[] getPDFByteStream() throws IOException {
    File file = new File("C:\\pdf\\bankAdminReport.pdf");

    byte[] b = new byte[(int) file.length()];
    try {
        FileInputStream fileInputStream = new FileInputStream(file);
        fileInputStream.read(b);
    } catch (FileNotFoundException e) {
        System.out.println("File Not Found.");
        e.printStackTrace();
    } catch (IOException e1) {
        System.out.println("Error Reading The File.");
        e1.printStackTrace();
    }
    return b;
}

主要的问题是，当我从本地驱动器发送文件读取，它发送完美。但如果我发送的数据库获取或任何本地变量文件损坏。

如果你对问题有任何疑问，请在下面评论。多谢了。

Answer 1

这个

byte[] bytes="0x255044462D312E330A25AAABAC".getBytes();

也将对前导的“0x＂进行编码。此外，您似乎试图将十六进制值转换为字节数组，而此方法将字符值转换为字节。

我相信你要找的是

byte[] bytes = java.xml.bind.DatatypeConverter.parseHexBinary("255044462D312E330A25AAABAC");