了解Rails ActionMailer编码

我对ActionMailer编码有点困惑。

标准操作邮件程序示例

app/mailers/example\u mailer。rb型

class ExampleMailer < ActionMailer::Base
  default from: "from@example.com"

  def sample_email(user)
    @user = user
    mail(to: @user.email, subject: 'Sample Email')
  end
end

应用程序/控制器/用户\u控制器。rb型

def create
  @user = User.new(user_params)

  respond_to do |format|
    if @user.save

      # Sends email to user when user is created.
      ExampleMailer.sample_email(@user).deliver_now

      format.html { redirect_to @user, notice: 'User was successfully created.' }
      format.json { render :show, status: :created, location: @user }
    else
      format.html { render :new }
      format.json { render json: @user.errors, status: :unprocessable_entity }
    end
  end
end

我的问题与

ExampleMailer.sample_email(@user).deliver_now

1. 怎样 ExampleMailer 通道 sample_email 方法不带 ExampleMailer.new ? sample\u电子邮件 不是类方法!

2. 怎样 deliver_now 呼叫 示例Mailer ?

我希望这是清楚的。感谢您的帮助。