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Handle EML file with JavaMailTag(s): Networking


Loading an .EML file
When saving an email to a file, the resulting file has an eml extension (email files--which are in RFC 822 format). This kind of file can be read and parsed by JavaMail. 
import java.util.*;
import java.io.*;
import javax.mail.*;
import javax.mail.internet.*;

public class ReadEmail {

   public static void main(String args[]) throws Exception{
       display(new File("C:\\temp\\message.eml"));

   }

   public static void display(File emlFile) throws Exception{
        Properties props = System.getProperties();
        props.put("mail.host", "smtp.dummydomain.com");
        props.put("mail.transport.protocol", "smtp");

        Session mailSession = Session.getDefaultInstance(props, null);
        InputStream source = new FileInputStream(emlFile);
        MimeMessage message = new MimeMessage(mailSession, source);


        System.out.println("Subject : " + message.getSubject());
        System.out.println("From : " + message.getFrom()[0]);
        System.out.println("--------------");
        System.out.println("Body : " +  message.getContent());
    }
}

A typical eml looks like this : 

X-Mozilla-Status: 0001
X-Mozilla-Status2: 00000000
Received: from tomts25-srv.bellnexxia.net
        (tomts25.bellnexxia.net [209.226.175.188])
    by tactika.com (8.9.3/8.9.3) with ESMTP id NAA07621
    for <real@rgagnon.com>; Sun, 1 Feb 2004 13:25:33 -0500 (EST)
Date: Sun, 01 Feb 2004 13:31:40 -0500
From: real gagnon <real@rgagnon.com>
Reply-To: real@rgagnon.com
User-Agent: Mozilla/5.0
   (Windows; U; Windows NT 5.1; en-US; rv:1.4)
   Gecko/20030624 Netscape/7.1 (ax)
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: real@rgagnon.com
Subject: Example for HowTo
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
X-UIDL: oP#!!c]^!!1;-!!T@1"!


This is an example for HowTo

Running the above HowTo gives this output : 

Subject : Example for HowTo
From : real gagnon <real@rgagnon.com>
--------------
Body :
This is an example for HowTo
Saving an email to .EML file
First you connect to the mail server with POP3 or IMAP protocol to retrieve the emails. 
      ...
      folder = store.getDefaultFolder().getFolder("INBOX");
      folder.open(Folder.READ_ONLY);
      Message[] messages = folder.getMessages();
      ...
      for (int i=0; i < messages.length; ++i) {
        Message msg = messages[i];
        String subject = msg.getSubject();
        processSaveToFile(msg, subject);
        ...
      }
      ...

Individual email are represented by the Message class. 

 private void processSaveToFile (javax.mail.Message msg, String subject)
   throws MessagingException, IOException
 {
   String whereToSave = "c:/temp/ + sanitizeFilename(subject) + ".eml";
   logger.info("Sauvegarde vers "+ whereToSave);
   OutputStream out = new FileOutputStream(new File(whereToSave));
   try {
       msg.writeTo(out);
   }
   finally {
       if (out != null) { out.flush(); out.close(); }
   }
 }
Since the subject is used to set the filename, it's not a bad idea to sanitize it to remove illegal characters. 
private static String sanitizeFilename(String name) {
   return name.replaceAll("[:\\\\/*?|<> \"]", "_");
}