Yii2使用swiftmailer发送邮件的方法

'mail' => [
    'class' => 'yiiswiftmailermailer',
    'viewpath' => '@backend/mail',
    'usefiletransport' => false,//set this property to false to send mails to real email addresses
    //comment the following array to send mail using php's mail function
    'transport' => [
      'class' => 'swift_smtptransport',
      'host' => 'smtp.gmail.com',
      'username' => 'username@gmail.com',
      'password' => 'password',
      'port' => '587',
      'encryption' => 'tls',
     ],
  ],
],

yii::$app->mail->compose('your_view', ['params' => $params])
 ->setfrom([yii::$app->params['supportemail'] => 'test mail'])
 ->setto('to_email@xx.com')
 ->setsubject('this is a test mail ' )
 ->send();