Swift Mailer 和前面介绍的PHPMailer一样，也是一个PHP邮件发送类。它不依赖于 PHP 自带的mail() 函数，因为该函数在发送多个邮件时占用的系统资源很高。Swift 直接与 SMTP 服务器通讯，具有非常高的发送速度和效率。

Swiftmailer的特点：

Send emails using SMTP, sendmail, postfix or a custom Transport implementation of your own

Support servers that require username & password and/or encryption

Protect from header injection attacks without stripping request data content

Send MIME compliant HTML/multipart emails

Use event-driven plugins to customize the library

Handle large attachments and inline/embedded images with low memory use

由于自己还没有用过，所以说以后自己使用以后再做补充。

官方网址：http://swiftmailer.org/

Swiftmailer的使用方法：

<?php

    require_once 'lib/swift_required.php';

    function sendMail() {

        $transport = Swift_SmtpTransport::newInstance('smtp.163.com', 25);

        $transport - > setUsername('username@163.com');

        $transport - > setPassword('password');

        $mailer = Swift_Mailer::newInstance($transport);

        $message = Swift_Message::newInstance();

        $message - > setFrom(array('username@163.com' = > 'name'));

        $message - > setTo(array('whoever@163.com' = > 'Mr.Right', 'whoever@qq.com' = > 'Mr.Wrong'));

        $message - > setSubject("This is a subject");

        $message - > setBody('Here is the message', 'text/html', 'utf-8');

        $message - > attach(Swift_Attachment::fromPath('pic.jpg', 'image/jpeg') - > setFilename('rename_pic.jpg'));

        try {

            $mailer - > send($message);

        } catch (Swift_ConnectionException $e) {

            echo 'There was a problem communicating with SMTP: '.$e - > getMessage();

        }

    }

?>