英文原文：http://emberjs.com/guides/controllers/representing-a-single-model-with-objectcontroller/

代表单一模型（Representing a Single Model）

Use Ember.ObjectController to represent a single model. To tell an ObjectController which model to represent, set its model property in your route’s setupController method.

Ember.ObjectController用于代表单一模型。通过在路由的setupController方法中设置ObjectController的model属性，来指定其代表的模型。

When a template asks an ObjectController for a property, it will first check to see if it has its own property with that name defined. If so, it will return its current value.

当模板向ObjectController请求属性时，控制器将首先检查是否定义有该属性，如果有，则返回其当前值。

However, if the controller does not have a property with that name defined, it will return the value of the property on the model.

然而，当控制器没有定义该属性时，就将返回其代表的模型的该属性的值。

For example, imagine you are writing a music player. You have defined your SongController to represent the currently playing song.

例如，在编写一个音乐播放器时，可以定义一个SongController来代表当前播放的歌曲。

  1. App.SongController = Ember.ObjectController.extend({
  2.   soundVolume: 1
  3. });

In your router, you set the model of the controller to the currently playing song:

在路由中，设置控制器的model属性为当前播放的歌曲。

  1. App.SongRoute = Ember.Route.extend({
  2.   setupController: function(controller, song) {
  3.     controller.set('model', song);
  4.   }
  5. });

In your template, you want to display the name of the currently playing song, as well as the volume at which it is playing.

在模板中，可以显示当前播放的歌曲的名称，以及播放的音量。

  1. <p>
  2.   <strong>Song</strong>: {{name}} by {{artist}}
  3. </p>
  4. <p>
  5.   <strong>Current Volume</strong>: {{soundVolume}}
  6. </p>

Because name and artist are persisted information, and thus stored on the model, the controller looks them up there and provides them to the template.

因为name和artist都是在模型中被持久化的信息，控制器从模型中获取这些信息，并提供给模板。

soundVolume, however, is specific to the current user’s session, and thus stored on the controller. The controller can return its own value without consulting the model.

然而soundVolume则是与当前用户回话相关的，并存储在控制器中，因此控制器可以直接返回其值。

The advantage of this architecture is that it is easy to get started by accessing the properties of the model via the object controller. If, however, you need to transform a model property for a template, there is a well-defined place to do so without adding view-specific concerns to the model.

这样的架构的优点是可以很容易的通过对象控制器来访问模型的属性。另外，如果需要为模板转换模型的属性，控制器是一个非常合适的地方来完成这样的工作，避免了将视图的逻辑放入到模型中去。

For example, imagine we want to display the duration of the song:

例如，音乐播放器需要显示歌曲的时长。

  1. <p>
  2.   <strong>Song</strong>: {{name}} by {{artist}}
  3. </p>
  4. <p>
  5.   <strong>Duration</strong>: {{duration}}
  6. </p>

This is saved on the server as an integer representing the number of seconds, so our first attempt looks like this:

由于时长在服务器端被保存为一个以秒为单位的整数，所以生成的html如下所示：

  1. <p>
  2.   <strong>Song</strong>: 4 Minute Warning by Radiohead
  3. </p>
  4. <p>
  5.   <strong>Duration</strong>: 257
  6. </p>

Since our users are humans and not robots, however, we’d like to display the duration as a formatted string.

由于音乐播放器的用户是人类而非机器，因此应该将歌曲时长显示为可读的格式。

This is very easy to do by defining a computed property on the controller which transforms the model’s value into a human-readable format for the template:

可以在控制器中定义一个计算属性来转换模型的值为一个对于模板来说更加具有可读性的属性。

  1. App.SongController = Ember.ObjectController.extend({
  2.   duration: function() {
  3.     var duration = this.get('model.duration'),
  4.          minutes = Math.floor(duration / 60),
  5.          seconds = duration % 60;
  7.     return [minutes, seconds].join(':');
  8.   }.property('model.duration')
  9. });

Now, the output of our template is a lot friendlier:

现在，模板的输出变得更加友好。

  1. <p>
  2.   <strong>Song</strong>: 4 Minute Warning by Radiohead
  3. </p>
  4. <p>
  5.   <strong>Duration</strong>: 4:17
  6. </p>