<%= form_for @user1 do |f| %>

    Username: <%= f.text_field :username %>      <br />
    Password: <%= f.password_field :password %>  <br />.
    Email:    <%= f.email_field :email %> <br />

    <%= submit_tag "Add" %>

<% end %>

I am new on ruby and I am trying create simple programs, but I have this error and I can't find out why. I have this error

我是Ruby的新手，我正在尝试创建简单的程序，但我有这个错误，我找不到原因。我有这个错误

undefined method `users_path' for #<#<Class:0x000000020576f0>:0x0000000335d5d8>

what is the solution here?

这里的解决方案是什么？

class UserController < ApplicationController
  def add
    @user1 = User.new
    respond_to do |format|
      format.html
      format.json {render :json => @user1}
    end
  end

优秀答案推荐

Did you define the routes in config/routes.rb?

您是否在CONFIG/routes.rb中定义了路由？

Rails.application.routes.draw do
  resources :users
  # ...
end

I got this error when in my config/routes.rb, I mistakenly had user (singular):

在我的配置/routes.rb中，我错误地将USER(单数)：

resources :user

It needs to be users (plural):

它需要是用户(复数)：

resources :users

If you run the rake routes command, you will find that there is no entry for users_path in the very first column. What that means is that you have no route defined for action that will be called when the form is submitted.

如果运行rake routes命令，您会发现在第一列中没有USERS_PATH的条目。这意味着您没有为提交表单时将调用的操作定义路由。

If you want to use resources, then just add:

如果您想要使用资源，则只需添加：

resources: users

and if you want to use a different URL(route name) for the users#new action, then add

如果要为USERS#new操作使用不同的URL(路由名)，则添加

resources: users, except: [:new]

below the route for users#new in the routes.rb file.

在routes.rb文件中用户#new的路径下方。

And, if you don't want to go the resources way then add a new route:

而且，如果你不想去资源的方式，然后添加一个新的路线：

post 'users', to: 'users#create'

In your config/routes.rb file add:

在您的配置/routes.rb文件中添加：

resources :users, except: [:new]

In your class UserController, use:

在您的类UserController中，使用：

route: get /signup, to: 'user#new'
.
.
resources :users

where ":users" is plural, because you will register multiple users.

其中“：USERS”是复数，因为您将注册多个用户。

This happens when we have a form and Rails doesn't know where to submit the form when we press the submit button.
For this, we need to go to routes and make sure we have resources:users:

当我们有一个表单，而当我们按下提交按钮时，Rails不知道在哪里提交表单时，就会发生这种情况。为此，我们需要转到Routes并确保我们拥有资源：用户：

Rails.application.routes.draw do

#all the other resources and routes

resources :users

end

In one of the other answers, I saw

在另一个答案中，我看到

resources :users, except[:new]

Use this only if we have already introduced the new action in the routes:

仅当我们已在路线中引入新操作时才使用此选项：

resources :posts

get 'signup', to: 'users#new 

resources :users, except[:new]

Based on your UserController, you should already have a route in the config/routes.rb file similar to this:

根据您的用户控制器，您应该已经在配置/routes.rb文件中有一个类似于以下内容的路由：

get 'users', to: 'user/#add'

In this case, Rails is going to look for a post users-route. So you need to define it too in the routes.rb file:

在本例中，Rails将寻找POST USER-ROUSE。因此，您也需要在routes.rb文件中定义它：

post 'users', to: 'user/#create'

To combine these two routes, you can simply add the following to your routes file:

要合并这两个路由，只需将以下内容添加到您的路由文件中：

resources: users

Which will automatically generate all the users related routes. You can have a look by typing in the terminal:

它将自动生成所有与用户相关的路线。您可以通过在终端中键入来查看：

rails routes