Java Cookbook

Sending MIME Mail

Problem

You need to send a multipart, MIME-encoded message.

Solution

Use the Part, man.

Discussion

Way back in the old days when the Internet was being invented, most email was composed using the seven-bit ASCII character set. You couldn’t send messages containing characters from international character sets. Then some enterprising soul got the idea to convert non-ASCII files into ASCII using a form of encoding known as UUENCODE (the UU is a reference to UUCP, one of the main transport protocols used for email and file transfer at a time when Internet access was prohibitively expensive for the masses). But this was pretty cumbersome, so eventually the Multimedia Internet Mail Exchange format, or MIME, was born. MIME has grown over the years to support, as its name implies, a variety of multimedia types in addition to supporting odd characters. MIME typing has become very pervasive due to its use on the Web. As you probably know, every file that your web browser downloads -- and a typical web page may contain from 1 to 20, 40, or more files depending on how hog-wild the graphics are -- is classified by the web server; this “MIME type” tells the browser how to display the contents of the file. Normal HTML pages are given a type of text/html. Plain text is, as you might guess, text/plain. Images have types such as image/gif, image/jpeg, image/png, and so on. Other types include application/ms-word, application/pdf, audio/au, etc.

Mail attachments are files attached ...