# You want to get exceptions in development,but not in production.
  unless Rails.application.config.consider_all_requests_local
    rescue_from ActionController::RoutingError,with: -> { render_404  }
  end

  def render_404
    respond_to do |format|
      format.html { render template: 'errors/not_found',status: 404 }
      format.all { render nothing: true,status: 404 }
    end
  end

我通常也拯救以下例外,但这取决于你：

rescue_from ActionController::UnknownController,with: -> { render_404  }
rescue_from ActiveRecord::RecordNotFound,with: -> { render_404  }

创建错误控制器：

class ErrorsController < ApplicationController
  def error_404
    render 'errors/not_found'
  end
end

然后在routes.rb

unless Rails.application.config.consider_all_requests_local
    # having created corresponding controller and action
    get '*path',to: 'errors#error_404',via: :all
  end

最后一点是在/ views / errors /下创建not_found.html.haml(或者你使用的任何模板引擎)：

%span 404
  %br
  Page Not Found