用Java-Mail發送附件無法正常工作

Question

我要發送帶附件的電子郵件。郵件的正文是正確的，但附件是空的。附件的大小正在顯示。那麼，怎麼了？

// Create the message part 
    BodyPart messageBodyPart = new MimeBodyPart(); 

    // Now set the actual message 
    messageBodyPart.setText(
      "Prozess vom " + new SimpleDateFormat("dd.MM.yyyy").format(new Date()) + " erfolgreich beendet"); 

    // Create a multipar message 
    Multipart multipart = new MimeMultipart(); 


    // Part two is attachment 
    BodyPart attachement = new MimeBodyPart(); 
    File fi = new File("C:" + File.separator + "Logdatei_Auto" + File.separator + "logdatei.txt"); 
    String filename = fi.getAbsolutePath(); 
    String name = fi.getName(); 
    javax.activation.DataSource source = new FileDataSource(filename); 
    attachement.setDataHandler(new DataHandler(source)); 
    attachement.setFileName(name); 
    multipart.addBodyPart(messageBodyPart); 
    multipart.addBodyPart(attachement); 

    // Send the complete message parts 
    message.setContent(multipart); 


    // Send message 
    Transport.send(message); 

UPDATE

終於將其與下面的代碼工作：

File filename = new File("logdatei.pdf"); 


    Properties props = new Properties(); 
    props.put("mail.transport.protocol", "smtp"); 
    props.put("mail.smtp.host", SMTP_HOST_NAME); 
    props.put("mail.smtp.auth", "true"); 
    props.put("mail.smtp.starttls.enable", "true"); 

    Authenticator auth = new SMTPAuthenticator(); 
    Session mailSession = Session.getDefaultInstance(props, auth); 
    // Create a default MimeMessage object. 
    // Create a default MimeMessage object. 
    try { 
      MimeMessage message = new MimeMessage(mailSession); 
      message.setFrom(new InternetAddress("*******")); 
      message.setRecipient(Message.RecipientType.TO, new InternetAddress("*******")); 
      message.setSubject("Test"); 
      message.setSentDate(new Date()); 

      // 
      // Set the email message text. 
      // 
      MimeBodyPart messagePart = new MimeBodyPart(); 
      messagePart.setText("Blah..."); 

      // 
      // Set the email attachment file 
      // 
      MimeBodyPart attachmentPart = new MimeBodyPart(); 
      FileDataSource fileDataSource = new FileDataSource(filename) { 
       @Override 
       public String getContentType() { 
        return "application/octet-stream"; 
       } 
      }; 
      attachmentPart.setDataHandler(new DataHandler(fileDataSource)); 
      attachmentPart.setFileName(filename.getName()); 

      Multipart multipart = new MimeMultipart(); 
      multipart.addBodyPart(messagePart); 
      multipart.addBodyPart(attachmentPart); 

      message.setContent(multipart); 

      Transport.send(message); 
     } catch (MessagingException e) { 
      e.printStackTrace(); 
     } 

感謝@所有

Answer 1

試試下面的代碼

MimeMultipart multipart = new MimeMultipart("mixed"); 
MimeBodyPart attachment = new MimeBodyPart(); 
attachment.setDisposition(Part.ATTACHMENT); 
attachment.setDataHandler(new DataHandler(new FileDataSource(file))); 
attachment.setFileName(file.getName()); 
multipart .addBodyPart(attachment); 
message.setContent(multipart); 

我想你錯過

attachment.setDisposition(Part.ATTACHMENT); 

所以基本上增加了Disposition爲Part.ATTACHMENT表示，這部分應作爲附件。

更新

下面的代碼發送電子郵件附件：

 try 
     { 
      Message message = new MimeMessage(session); 
      message.setFrom(new InternetAddress("fromEmailAddress")); 
      message.setRecipients(Message.RecipientType.TO, InternetAddress.parse("toEmailAddress")); 
      message.setSubject("message with attachment"); 
      message.setContent("Hi", "text/plain; charset=UTF-8"); 


      File file = File.createTempFile("test", ".csv"); 
      FileOutputStream fileOutputStream = new FileOutputStream(file); 
      OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fileOutputStream, Charset.forName("UTF-8").newEncoder()); 
      PrintWriter writer = new PrintWriter(outputStreamWriter); 
      writer.println("\u20ac;"); 
      writer.println("€"); 
      writer.flush(); 

      MimeMultipart rootMultipart = new MimeMultipart("mixed"); 
      MimeBodyPart bodyPart = new MimeBodyPart(); 
      bodyPart.setDisposition(Part.ATTACHMENT); 
      bodyPart.setDataHandler(new DataHandler(new FileDataSource(file))); 
      bodyPart.setFileName(file.getName()); 
      rootMultipart.addBodyPart(bodyPart); 
      message.setContent(rootMultipart); 

      Transport.send(message); 

      writer.close(); 
      file.delete(); 
      System.out.println("Message sent successfully!"); 

     } 
     catch (MessagingException e) 
     { 
      throw new RuntimeException(e); 
     } 
     catch (IOException e) 
     { 
      e.printStackTrace(); 
     }