Attach a file in Email Using Java

From CodeCodex

How can we Add an attachment and send it using it via e-mail. Here is a complete code Example.


Get Attachment File Name


import java.util.Properties;

import javax.mail.Authenticator;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.Part;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.URLName;
import javax.mail.internet.InternetAddress;

public class MainClass {

  public static void main(String[] args) throws Exception {
    URLName server = new URLName("protocol://username@host/foldername");

    Session session = Session.getDefaultInstance(new Properties(), new MailAuthenticator());

    Folder folder = session.getFolder(server);
    if (folder == null) {
      System.out.println("Folder " + server.getFile() + " not found.");
      System.exit(1);
    }
    folder.open(Folder.READ_ONLY);

    Message[] messages = folder.getMessages();
    for (int i = 0; i < messages.length; i++) {
      System.out.println(messages[i].getSize() + " bytes long.");
      System.out.println(messages[i].getLineCount() + " lines.");
      String disposition = messages[i].getDisposition();
      if (disposition == null){
        ; // do nothing
      }else if (disposition.equals(Part.INLINE)) {
        System.out.println("This part should be displayed inline");
      } else if (disposition.equals(Part.ATTACHMENT)) {
        System.out.println("This part is an attachment");
        String fileName = messages[i].getFileName();
        System.out.println("The file name of this attachment is " + fileName);
      }
      String description = messages[i].getDescription();
      if (description != null) {
        System.out.println("The description of this message is " + description);
      }
    }
    folder.close(false);
  }
}

class MailAuthenticator extends Authenticator {

  public MailAuthenticator() {
  }

  public PasswordAuthentication getPasswordAuthentication() {
    return new PasswordAuthentication("username", "password");
  }
}


How to use the FileDataSource to send a file via mail


import java.util.*;
import java.io.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;



public class sendfile {

    public static void main(String[] args) {
  if (args.length != 5) {
      System.out.println("usage: java sendfile <to> <from> <smtp> <file> true|false");
      System.exit(1);
  }

  String to = args[0];
  String from = args[1];
  String host = args[2];
  String filename = args[3];
  boolean debug = Boolean.valueOf(args[4]).booleanValue();
  String msgText1 = "Sending a file.\n";
  String subject = "Sending a file";
  
  // create some properties and get the default Session
  Properties props = System.getProperties();
  props.put("mail.smtp.host", host);
  
  Session session = Session.getInstance(props, null);
  session.setDebug(debug);
  
  try {
      // create a message
      MimeMessage msg = new MimeMessage(session);
      msg.setFrom(new InternetAddress(from));
      InternetAddress[] address = {new InternetAddress(to)};
      msg.setRecipients(Message.RecipientType.TO, address);
      msg.setSubject(subject);

      // create and fill the first message part
      MimeBodyPart mbp1 = new MimeBodyPart();
      mbp1.setText(msgText1);

      // create the second message part
      MimeBodyPart mbp2 = new MimeBodyPart();

            // attach the file to the message
        FileDataSource fds = new FileDataSource(filename);
      mbp2.setDataHandler(new DataHandler(fds));
      mbp2.setFileName(fds.getName());

      // create the Multipart and add its parts to it
      Multipart mp = new MimeMultipart();
      mp.addBodyPart(mbp1);
      mp.addBodyPart(mbp2);

      // add the Multipart to the message
      msg.setContent(mp);

      // set the Date: header
      msg.setSentDate(new Date());
      
      // send the message
      Transport.send(msg);
      
  } catch (MessagingException mex) {
      mex.printStackTrace();
      Exception ex = null;
      if ((ex = mex.getNextException()) != null) {
    ex.printStackTrace();
      }
  }
    }
}