Blog : Send e-mail with attachment in Java

Send e-mail with attachment in Java

This article provides a step-by-step guide on how to add attachments to an e-mail message to be sent via a SMTP server, using the JavaMail API. To understand how attachments are stored inside an e-mail message

As we can see, a message comprises of a header and a body. The body must be of type Multipartfor containing attachments. The Multipart object holds multiple parts in which each part is represented as a type of BodyPart whose subclass, MimeBodyPart – can take a file as its content. The steps to create a multipart message with multiple parts are as follows:

Message message = new MimeMessage(session);

Multipart multipart = new MimeMultipart();

// creates body part for the message

MimeBodyPart messageBodyPart = new MimeBodyPart();

messageBodyPart.setContent(message, "text/html");

// creates body part for the attachment

MimeBodyPart attachPart = new MimeBodyPart();

// code to add attachment...will be revealed later

// adds parts to the multipart

multipart.addBodyPart(messageBodyPart);

multipart.addBodyPart(attachPart);

// sets the multipart as message's content

message.setContent(multipart);

The MimeBodyPart class provides some convenient methods for attaching a file, but the way is different between JavaMail 1.3 and JavaMail 1.4. With JavaMail 1.3, it requires writing the following code to add an attachment:

// JavaMail 1.3

MimeBodyPart attachPart = new MimeBodyPart();

String attachFile = "D:/Documents/MyFile.mp4";

DataSource source = new FileDataSource(attachFile);

attachPart.setDataHandler(new DataHandler(source));

attachPart.setFileName(new File(attachFile).getName());

multipart.addBodyPart(attachPart);

With JavaMail 1.4, adding an attachment is much simpler with the following new methods introduced in the MimeBodyPart class:

  void attachFile(File file)
  void attachFile(String filePath)

So the code with JavaMail 1.4 would look like this:

// JavaMail 1.4

MimeBodyPart attachPart = new MimeBodyPart();

String attachFile = "D:/Documents/MyFile.mp4";

attachPart.attachFile(attachFile);

multipart.addBodyPart(attachPart);

The code for JavaMail 1.3 still works in 1.4. Now for a sample program, the following class, EmailAttachmentSender – implements a static method, sendEmailWithAttachments() – which can be used for sending an e-mail message with some attachments. This method requires the following parameters:

  For SMTP server information: host, port number, user name (e-mail address), and password.
  For e-mail message: recipient e-mail address, subject, and message.
  For attached files: an array of String for file paths.

Here is the code of the class EmailAttachmentSender:

package net.codejava.mail;

import java.io.IOException;

import java.util.Date;

import java.util.Properties;

import javax.mail.Authenticator;

import javax.mail.Message;

import javax.mail.MessagingException;

import javax.mail.Multipart;

import javax.mail.PasswordAuthentication;

import javax.mail.Session;

import javax.mail.Transport;

import javax.mail.internet.AddressException;

import javax.mail.internet.InternetAddress;

import javax.mail.internet.MimeBodyPart;

import javax.mail.internet.MimeMessage;

import javax.mail.internet.MimeMultipart;

public class EmailAttachmentSender {

public static void sendEmailWithAttachments(String host, String port,

final String userName, final String password, String toAddress,

String subject, String message, String[] attachFiles)

throws AddressException, MessagingException {

// sets SMTP server properties

Properties properties = new Properties();

properties.put("mail.smtp.host", host);

properties.put("mail.smtp.port", port);

properties.put("mail.smtp.auth", "true");

properties.put("mail.smtp.starttls.enable", "true");

properties.put("mail.user", userName);

properties.put("mail.password", password);

// creates a new session with an authenticator

Authenticator auth = new Authenticator() {

public PasswordAuthentication getPasswordAuthentication() {

return new PasswordAuthentication(userName, password);
}
};

Session session = Session.getInstance(properties, auth);

// creates a new e-mail message

Message msg = new MimeMessage(session);

msg.setFrom(new InternetAddress(userName));

InternetAddress[] toAddresses = { new InternetAddress(toAddress) };

msg.setRecipients(Message.RecipientType.TO, toAddresses);

msg.setSubject(subject);

msg.setSentDate(new Date());

// creates message part

MimeBodyPart messageBodyPart = new MimeBodyPart();

messageBodyPart.setContent(message, "text/html");

// creates multi-part

Multipart multipart = new MimeMultipart();

multipart.addBodyPart(messageBodyPart);

// adds attachments

if (attachFiles != null && attachFiles.length > 0) {

for (String filePath : attachFiles) {

MimeBodyPart attachPart = new MimeBodyPart();

try {

attachPart.attachFile(filePath);

} catch (IOException ex) {

ex.printStackTrace();

}

multipart.addBodyPart(attachPart);

}

}

// sets the multi-part as e-mail's content

msg.setContent(multipart);

// sends the e-mail

Transport.send(msg);

}

/**

* Test sending e-mail with attachments

*/

public static void main(String[] args) {

// SMTP info

String host = "smtp.gmail.com";

String port = "587";

String mailFrom = "your-email-address";

String password = "your-email-password";

// message info

String mailTo = "your-friend-email";

String subject = "New email with attachments";

String message = "I have some attachments for you.";

// attachments

String[] attachFiles = new String[3];

attachFiles[0] = "e:/Test/Picture.png";

attachFiles[1] = "e:/Test/Music.mp3";

attachFiles[2] = "e:/Test/Video.mp4";

try {

sendEmailWithAttachments(host, port, mailFrom, password, mailTo,

subject, message, attachFiles);

System.out.println("Email sent.");

} catch (Exception ex) {

System.out.println("Could not send email.");

ex.printStackTrace();

}

}

}