NoMethodError虽然方法已经定义

我有一个Ruby On Rails博客应用程序，并且NoMethodError in PostsController#show在打开帖子时遇到问题。PostsController存储在rails/weblog/app/controllers

我得到undefined method 'set_current_page' for #<PostsController:0x007fb162831e70>set_current_page的定义是这样的：

  private 
   def set_current_page 
      @current_page = params[:page] || 1 
   end
end

然后用在 before_action

before_action :set_current_page, except: [:index]
before_action :set_post, only: [:show, :edit, :update, :destroy]

完整堆栈跟踪：

activesupport (5.0.0.1) lib/active_support/callbacks.rb:382:in `block in make_lambda'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:150:in `block (2 levels) in halting_and_conditional'
actionpack (5.0.0.1) lib/abstract_controller/callbacks.rb:12:in `block (2 levels) in <module:Callbacks>'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:151:in `block in halting_and_conditional'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:454:in `block in call'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:454:in `each'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:454:in `call'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:101:in `__run_callbacks__'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:750:in `_run_process_action_callbacks'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:90:in `run_callbacks'
actionpack (5.0.0.1) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (5.0.0.1) lib/action_controller/metal/rescue.rb:20:in `process_action'
actionpack (5.0.0.1) lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
activesupport (5.0.0.1) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (5.0.0.1) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (5.0.0.1) lib/active_support/notifications.rb:164:in `instrument'
actionpack (5.0.0.1) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (5.0.0.1) lib/action_controller/metal/params_wrapper.rb:248:in `process_action'
activerecord (5.0.0.1) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (5.0.0.1) lib/abstract_controller/base.rb:126:in `process'
actionview (5.0.0.1) lib/action_view/rendering.rb:30:in `process'
actionpack (5.0.0.1) lib/action_controller/metal.rb:190:in `dispatch'
actionpack (5.0.0.1) lib/action_controller/metal.rb:262:in `dispatch'
actionpack (5.0.0.1) lib/action_dispatch/routing/route_set.rb:50:in `dispatch'
actionpack (5.0.0.1) lib/action_dispatch/routing/route_set.rb:32:in `serve'
actionpack (5.0.0.1) lib/action_dispatch/journey/router.rb:39:in `block in serve'
actionpack (5.0.0.1) lib/action_dispatch/journey/router.rb:26:in `each'
actionpack (5.0.0.1) lib/action_dispatch/journey/router.rb:26:in `serve'
actionpack (5.0.0.1) lib/action_dispatch/routing/route_set.rb:725:in `call'
rack (2.0.1) lib/rack/etag.rb:25:in `call'
rack (2.0.1) lib/rack/conditional_get.rb:25:in `call'
rack (2.0.1) lib/rack/head.rb:12:in `call'
rack (2.0.1) lib/rack/session/abstract/id.rb:222:in `context'
rack (2.0.1) lib/rack/session/abstract/id.rb:216:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/cookies.rb:613:in `call'
activerecord (5.0.0.1) lib/active_record/migration.rb:552:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/callbacks.rb:38:in `block in call'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:97:in `__run_callbacks__'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:750:in `_run_call_callbacks'
activesupport (5.0.0.1) lib/active_support/callbacks.rb:90:in `run_callbacks'
actionpack (5.0.0.1) lib/action_dispatch/middleware/callbacks.rb:36:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/executor.rb:12:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/remote_ip.rb:79:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/debug_exceptions.rb:49:in `call'
web-console (3.4.0) lib/web_console/middleware.rb:135:in `call_app'
web-console (3.4.0) lib/web_console/middleware.rb:28:in `block in call'
web-console (3.4.0) lib/web_console/middleware.rb:18:in `catch'
web-console (3.4.0) lib/web_console/middleware.rb:18:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/show_exceptions.rb:31:in `call'
railties (5.0.0.1) lib/rails/rack/logger.rb:36:in `call_app'
railties (5.0.0.1) lib/rails/rack/logger.rb:24:in `block in call'
activesupport (5.0.0.1) lib/active_support/tagged_logging.rb:70:in `block in tagged'
activesupport (5.0.0.1) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (5.0.0.1) lib/active_support/tagged_logging.rb:70:in `tagged'
railties (5.0.0.1) lib/rails/rack/logger.rb:24:in `call'
sprockets-rails (3.2.0) lib/sprockets/rails/quiet_assets.rb:13:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/request_id.rb:24:in `call'
rack (2.0.1) lib/rack/method_override.rb:22:in `call'
rack (2.0.1) lib/rack/runtime.rb:22:in `call'
activesupport (5.0.0.1) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/executor.rb:12:in `call'
actionpack (5.0.0.1) lib/action_dispatch/middleware/static.rb:136:in `call'
rack (2.0.1) lib/rack/sendfile.rb:111:in `call'
railties (5.0.0.1) lib/rails/engine.rb:522:in `call'
puma (3.6.0) lib/puma/configuration.rb:225:in `call'
puma (3.6.0) lib/puma/server.rb:578:in `handle_request'
puma (3.6.0) lib/puma/server.rb:415:in `process_client'
puma (3.6.0) lib/puma/server.rb:275:in `block in run'
puma (3.6.0) lib/puma/thread_pool.rb:116:in `block in spawn_thread'

posts_controller.rb文件：

class PostsController < ApplicationController
    before_action :set_current_page, except: [:index]
    before_action :set_post, only: [:show, :edit, :update, :destroy]

    # GET /posts
    # GET /posts.json
    def index
        @posts = Post.paginate(page: params[:page],
                            per_page: params[:per_page])
                            .order('title, user_id')
    end

    # GET /posts/1
    # GET /posts/1.json
    def show
    end

    # GET /posts/new
    def new
        @post = Post.new
    end

    # GET /posts/1/edit
    def edit
    end

    # POST /posts
    # POST /posts.json
    def create
        @post = Post.new(post_params)
        @post.user = User.find_by email: params[:email]

        respond_to do |format|
            if @post.save
                format.html { redirect_to (post_url(@post, page: @current_page)), notice: 'Post was successfully created.' }
                format.json { render :show, status: :created, location: @post }
            else
                format.html { render :new }
                format.json { render json: @post.errors, status: :unprocessable_entity }
            end
        end
    end

    # PATCH/PUT /posts/1
    # PATCH/PUT /posts/1.json
    def update
        @post.user = User.find_by email: params[:email]
        respond_to do |format|
            if @post.update(post_params)
                format.html { redirect_to (post_url(@post, page: @current_page)), notice: 'Post was successfully updated.' }
                format.json { render :show, status: :ok, location: @post }
            else
                format.html { render :edit }
                format.json { render json: @post.errors, status: :unprocessable_entity }
            send
        end
    end

    # DELETE /posts/1
    # DELETE /posts/1.json
    def destroy
        @post.destroy
        respond_to do |format|
            format.html { redirect_to posts_url(page: @current_page), notice: 'Post was successfully destroyed.' }
            format.json { head :no_content }
        end
    end

    private
        # Use callbacks to share common setup or constraints between actions.
        def set_post
            @post = Post.find(params[:id])
        end

        def set_current_page
            @current_page = params[:page] || 1
        end

        # Never trust parameters from the scary internet, only allow the white list through.
        def post_params
            params.require(:post).permit(:title, :body, :page)
        end
    end
end