Ruby on rails 4 ActiveModel:：禁止BooksController中的属性错误#创建 我对ruby和rails都是新手，现在我正在使用Rails4和Eclipse IDE开发一个应用程序。该应用程序是库应用程序。功能主义者是新的，创建书籍、显示、列出、删除和编辑书籍等。 我在浏览器中输入http://127.0.0.1:3000/books/new 当我点击按钮时，它显示了一个带有标题、价格、主题和描述的表单，并显示了下面的错误 ActiveModel:：禁止BooksController中的属性错误#创建 ActiveModel:：禁止属性错误 def创建 @book=book.new（params[：book]）——这是第13行 如果@book.save 重定向到：action=>“list” ActiveModel:：ForbiddenAttribute错误（ActiveModel:：ForbiddenAttribute错误）： app/controllers/books\u controller.rb:13:in'create' 呈现c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/actionpack-4.0.3/lib/action\u dispatch/middleware/templates/rescues//u source.erb（0.0ms）。。。。。 它有两种型号 book.rb 类目“错误消息”的数值性 结束 subject.rb 类主题“新建” 结束 结束 私有的 def book_参数 参数要求（：书）。许可（：标题，：价格，：主题，：描述） 结束 定义编辑 @book=book.find（参数[：id]） @主题=主题。查找（：全部） 结束 def更新 @book=book.find（参数[：id]） 如果@book.update_属性（参数[：book]） 重定向到：action=>'show'，：id=>@book 其他的 @主题=主题。查找（：全部） 呈现：操作=>“编辑” 结束 结束 def删除 Book.find（params[：id]）.destroy 重定向到：action=>“list” 结束 def show_主题 @subject=subject.find（参数[：id]） 结束 结束 路由文件是 routes.rb LibrayWebApplication:：Application.routes.draw do 获取“书籍/新” 发布“书籍/创建” 获取“书籍/列表” 获取“书籍/展览” 获取“书籍/编辑” 获取“书籍/展示主题” 结束 并且视图文件是 new.erb 添加新书 “创建“%”

标题：

价格：

主题：

说明

'列表'}%> 数据库包含带有字段的表，但它不存储数据，而是显示错误，因为我是新来的。它花费了我很多时间，它显示了一个带有字段标题、价格、主题和描述的表单，当我单击按钮时，显示了以下错误

            I am new to ruby as well as rails, now I am developing an application using Rails4 and Eclipse IDE..the application is Library application the functionalists are new,create a book,show,list,delete and edit book etc.
            I enter in the browser http://127.0.0.1:3000/books/new it shows a form with fields title,price,subject and description and create button when I clicked the button its showing the following error
            ActiveModel::ForbiddenAttributesError in BooksController#create
            ActiveModel::ForbiddenAttributesError

              def create
                  @book = Book.new(params[:book])--------it is line no 13
                  if @book.save
                        redirect_to :action => 'list'
             ActiveModel::ForbiddenAttributesError (ActiveModel::ForbiddenAttributesError):
              app/controllers/books_controller.rb:13:in `create'


              Rendered c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/actionpack-4.0.3/lib/action_dispatch/middleware/templates/rescues/_source.erb (0.0ms).....

            It having two models
            book.rb
            class Book < ActiveRecord::Base
                belongs_to :subject
               validates_presence_of :title
              validates_numericality_of :price, :message=>"Error Message"
            end
            subject.rb
            class Subject < ActiveRecord::Base
                has_many :books
            end
            the controller is 
            books_controller.rb

            class BooksController < ApplicationController
               def list
                  @books = Book.find(:all)
               end
               def show
                  @book = Book.find(params[:id])
               end
               def new
                  @book = Book.new
                  @subjects = Subject.find(:all)
               end
               def create
                  @book = Book.new(params[:book])
                  if @book.save
                        redirect_to :action => 'list'
                  else
                        @subjects = Subject.find(:all)
                        render :action => 'new'
                  end
               end
               private 
               def book_params
               params.require(:book).permit(:Title,:Price,:Subject,:Description)
               end

                  def edit
                  @book = Book.find(params[:id])
                  @subjects = Subject.find(:all)
               end
               def update
                  @book = Book.find(params[:id])
                  if @book.update_attributes(params[:book])
                     redirect_to :action => 'show', :id => @book
                  else
                     @subjects = Subject.find(:all)
                     render :action => 'edit'
                  end
               end
               def delete
                  Book.find(params[:id]).destroy
                  redirect_to :action => 'list'
               end
               def show_subjects
                  @subject = Subject.find(params[:id])
               end
            end
            route file is
            routes.rb
            LibrarayWebApplication::Application.routes.draw do
                get 'books/new'
                post 'books/create'
              get 'books/list'
               get 'books/show'
              get 'books/edit'
             get 'books/show_subjects'
            end
            and the view file is 

            new.erb
            <h1>Add new book</h1>
            <%= form_tag :action => 'create' %>
            <p><label for="book_title">Title</label>:
            <%= text_field 'book', 'title' %></p>
            <p><label for="book_price">Price</label>:
            <%= text_field 'book', 'price' %></p>
            <p><label for="book_subject">Subject</label>:
            <%= collection_select(:book,:subject_id,@subjects,:id,:name) %></p>
            <p><label for="book_description">Description</label><br/>
            <%= text_area 'book', 'description' %></p>
            <%= submit_tag "Create" %>
            <%= link_to 'Back', {:action => 'list'} %>

迁移文件是
迁移是在两个表中创建的。
20140318084539_books.rb
#它在mysql数据库中创建了books表
类目32，：null=>false
t、 列：价格，：浮动
t、 列：subject_id，：integer
t、 列：说明，：文本
t、 列：创建时间：：时间戳
结束
结束
def自动关闭
放下桌子：书
结束
结束
20140318084609_subjects.rb
#它是在数据库中的subjects表中创建的
类主题“物理”
Subject.create:name=>“数学”
结束
def自动关闭
下表：受试者
结束
我无法解决这个问题
访问该方法时，以下代码将显示主题列表
我无法解决这个问题
我在books\u controller.rb文件中使用了强参数

            migration files are
            migrations are created the both the tables.

                 20140318084539_books.rb 
        #its created the books table in the mysql database

                    class Books < ActiveRecord::Migration
                     def self.up
                         create_table :books do |t|
                      t.column :title, :string, :limit => 32, :null => false
                      t.column :price, :float
                      t.column :subject_id, :integer
                      t.column :description, :text
                      t.column :created_at, :timestamp
                         end
                      end

                      def self.down
                        drop_table :books
                      end
                    end

                20140318084609_subjects.rb
            #it is created the subjects table in the database
                    class Subjects < ActiveRecord::Migration
                      def self.up
                          create_table :subjects do |t|
                           t.column :name, :string

                        Subject.create :name => "Physics"
                        Subject.create :name => "Mathematics"
                        end
                      def self.down
                          drop_table :subjects
                      end  end

I am unable to solve this issue
       the following code will displays the list of subjects when accessing the method
    I am unable to solve this issue
    I used the Strong Parameters in books_controller.rb file

def book_params
  params.require(:book).permit(:title,:price,:subject,:description)
end


def create
  @book = Book.new(book_params)
  if @book.save
       redirect_to :action => 'list'
   else
       @subjects = Subject.find(:all)
       render :action => 'new'
   end
 end