def update
p "====================="
    @blog = Blog.find(params[:blog_id])
    if @blog
      @blog.update_attributes(params[:blog])
      @blog.save
      redirect_to :action => :index
    else
      redirect_to :action => :new
    end
  end

<%= form_for(@blog, {:url => {:action => :update,:blog_id => @blog.id}}) do |f| %>
   <h3>blog , world!</h3>

        <p>This is a template for a simple marketing or informational website. It includes a large callout called a
          jumbotron and three supporting pieces of content. Use it as a starting point to create something more
          unique.</p>
        <div class="input-group input-group-lg" style="width: 1000px">
          <%= f.text_field :title,:class => "form-control", :placeholder => "title" %>
        </div>

        <%= f.text_area :content,:id => "myEditor", :rows => 40, :cols => 120 %>

        <label>分类：</label><%= f.select :blog_type_id, options_from_collection_for_select(@blog_types, "id", "name") %>
        <br/>
        <%= f.submit "发表日志", :class => 'btn btn-lg btn-primary' %>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
        <%= f.button "保存草稿", :class => 'btn btn-lg btn-primary' %>
        <br/><br/>
 <% end %>

对数据进行修改，然后提交到 update，不打印 P，但是可以看到提交的参数，最后渲染 update 页面，迷惑