(c) copyright 2003-2009 Amichai Rothman
What is TNEF?
Transport-Neutral Encapsulation Format (TNEF) is Microsoft's non-standard
format for encapsulating mail which has any non-plain-text content or
properties (such as rich text, embedded OLE objects, voting buttons, and
sometimes just attachments). Whether or not a given message is encoded
using TNEF is determined by the Outlook default settings, per-recipient
setting, Exchange Server settings, and message type and content.
Once a TNEF message is used, the entire message, including all the
original attachments and properties, is encapsulated in a single
attachment of mime type "application/ms-tnef" added to the message to be
sent over the Internet. This attachment is usually named "WINMAIL.DAT",
and when sent to any non-MS mail client, is useless, and makes access to
the original message attachments impossible.What is the Java TNEF package?
The Java TNEF package is an open-source implementation of a TNEF message
handler, which can be used as a command-line utility or integrated into
Java-based mail applications to extract the original message content.How do I use the Java TNEF package?
The TNEF package is written in pure Java, and thus requires no special
installation. Just add the "tnef.jar" file to your classpath.
If you are an end user getting strange attachments named "WINMAIL.DAT" or
"ATT00001.DAT", instead of other expected attachments, you can simply run
the net.freeutils.tnef.TNEF class from the command line to extract the original
attachments from such a TNEF file.
If you are a Java developer working on a mail client or server, and need
to handle TNEF attachments (because whether u like it or not, they're out
there in real-world messages), you have several choices:
1. Low-level: you can use the TNEFInputStream class to read TNEF
attributes, which are the basic unit in a TNEF stream, and do with
them as you please.
2. Middle-level: the net.freeutils.tnef package gives you access to the
entire TNEF content through simple Java objects representing the
underlying TNEF data structures. You can use these classes to
access all TNEF attributes and MAPI properties that were sent with
the message.
For example, you can choose to implement voting buttons or receipt
notifications in your Java application by finding and interpreting
the appropriate MAPI properties. This requires knowledge of the
MAPI properties and their meaning.
3. High-level: The net.freeutils.tnef.TNEF class is a simple example of
using these middle-level classes to display the message properties
and extract the attachments. You can use it directly from your
application, or just browse the source code for an example of how
to do things yourself.
The net.freeutils.tnef.mime package gives you high-level access to the
TNEF message using the JavaMail API. The TNEFMime class is a simple
example of using these classes, and allows you to extract a TNEF
attachment from a mime message (which can then be processed using the
TNEF or TNEFMime classes) or to convert a TNEF attachment or a message
containing a TNEF attachment to an equivalent standard mime message
with the original header fields and attachments, including read
receipt notification conversion and contact to vCard conversion, etc.
This package is still considered experimental (though it's already
being used in production grade systems), so go ahead and experiment
with it!
The net.freeutils.tnef.msg package contains a proof-of-concept .msg
file handler. The Msg class uses Jakarta's POI project and provides
a simple API for reading a .msg file into a net.freeutils.tnef.Message
instance for access to its MAPI properties and attachments.License
The Java TNEF package is provided under the GNU General Public License
agreement. Please read the full license agreement in the included
LICENSE.txt file.
For non-GPL commercial licensing please contact the address below.Contact
Please write to support@freeutils.net with any bugs, suggestions, fixes,
contributions, or just to drop a good word and let me know you've found
this package useful and you'd like it to keep being maintained.
Updates and additional info can be found at http://www.freeutils.net/source/jtnef/