java - 如何添加文件找不到此代码的异常(exception)？

Question

我使用此代码使用Java发送邮件。在这里，我将pdf文件附加到邮件中。如果找不到文件，我想抛出，但找不到文件异常。该怎么办？

    try{
    Message message = new MimeMessage(session);
    message.setFrom(new InternetAddress(from));
    message.addRecipient(Message.RecipientType.TO, new InternetAddress(receiver));
    message.setSubject(subject);
    // Create the message part
    BodyPart messageBodyPart = new MimeBodyPart();
    // Fill the message
    messageBodyPart.setText("hai");
    Multipart multipart = new MimeMultipart();
    multipart.addBodyPart(messageBodyPart);
    //Attachement
    messageBodyPart = new MimeBodyPart();
    String filename = "file";
        DataSource source = new FileDataSource(filename);
        messageBodyPart.setDataHandler(new DataHandler(source));
        messageBodyPart.setFileName(source.getName());
        multipart.addBodyPart(messageBodyPart);
    }
    message.setContent(multipart);
    Transport transport = session.getTransport("smtp");
    try{
        transport.connect(host,from,password);
    } catch (AuthenticationFailedException err){
        String errMsg = "Authentication fails when sending mail. Sent failed to " + receiver;
        log.error(errMsg,err);
        throw new AuthenticationFailedException(errMsg + err.getMessage());
    }
    transport.send(message);
} catch (MessagingException re) {
    String localizedError = "Unexpected error occurred at Email client. Sent failed to:" + receiver + ". ";
    log.error(localizedError + re.getLocalizedMessage(), re);
    throw new MessagingException(localizedError + re.getLocalizedMessage(), re);
}

这是我要添加文件的代码未找到异常

Answer 1

我本以为FileDataSource或DataHandler都可以做到这一点，但如果没有，只需添加:

new FileInputStream(filename).close();

在将filename参数传递给FileDataSource之前。
它将为您抛出该异常。