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ruby on rails错误undefined method `title' for nil:NilClass

首先搞清楚这句话,在 Ruby 中,方法分为publicprivateprotected 三种,只有 public 方法才能作为控制器的动作。

我的出错的代码如下:

controlle

class ArticlesController < ApplicationController
	def new 
	end

	def create
		params.permit!  
		@article = Article.new(params[:article])

		@article.save
		redirect_to @article
	end

	private
  		def article_params
    	params.required(:article).permit(:title, :text)
  	end

  	def show 
  		@article = Article.find(params[:id])
  	end
end

view show.html.erb

<p>
	<strong>Title:</strong>
	<%= @article.title %>
</p>

<p>
	<strong>Text;</strong>
	<%= @article.text %>
</p>

报错说是:

NoMethodError in Articles#show

Showing /home/huihui/Documents/ruby/blog/app/views/articles/show.html.erb where line #3 raised:

undefined method `title‘ for nil:NilClass

解决方法是:

在controlle文件里:

class ArticlesController < ApplicationController
	def new 
	end

	def create
		params.permit!  
		@article = Article.new(params[:article])

		@article.save
		redirect_to @article
	end

  	def show 
  		@article = Article.find(params[:id])
  	end

  	private
  		def article_params
    	params.required(:article).permit(:title, :text)
  	end
end

把show方法改成公有的就好啦