基本用法
$mail = new PHPMailer(true);        try {            $mail->SMTPDebug = SMTP::DEBUG_OFF;                      // Enable verbose debug output            $mail->isSMTP();                                            // Send using SMTP            $mail->Host       = 'smtp.163.com';                    // Set the SMTP server to send through            $mail->SMTPAuth   = true;                                   // Enable SMTP authentication            $mail->Username   = 'xxx@163.com';                     // SMTP username            $mail->Password   = 'xxx';                               // SMTP password            $mail->SMTPSecure = PHPMailer::ENCRYPTION_SMTPS;         // Enable TLS encryption; `PHPMailer::ENCRYPTION_SMTPS` also accepted            $mail->Port       = 465;                                    // TCP port to connect to            //Recipients            $mail->setFrom('xxx@163.com', '意见和反馈');            $mail->addAddress('xxx@qq.com');     // Add a recipient            //$mail->addReplyTo('info@example.com', 'Information');            //$mail->addCC('cc@example.com');            //$mail->addBCC('bcc@example.com');            // Attachments            //$mail->addAttachment('/var/tmp/file.tar.gz');         // Add attachments            //$mail->addAttachment('/tmp/image.jpg', 'new.jpg');    // Optional name            // Content            $mail->isHTML(true);                                  // Set email format to HTML            $mail->Subject = 'xxx';            $mail->Body    = $html;            $mail->AltBody = 'This is the body in plain text for non-HTML mail clients';            $mail->send();        } catch (Exception $e) {            Db::name('error_log')->insert([                'type' => __CLASS__.'.'.__METHOD__,                'content' => $e->getMessage().';'.$mail->ErrorInfo,            ]);            throw new \Exception($mail->ErrorInfo);        }