Models, which contain or represent the data that users work with. These can be simple view models, which just represent data being transferred between views and controllers; or they can be domain models, which contain the data in a business domain as well as the operations, transformations, and rules for
manipulating that data.
Views, which are used to render some part of the model as a UI.
Controllers, which process incoming requests, perform operations on the model,and select views to render to the user.
模型：包含用户要处理的数据，分为view models和domain models，业务逻辑放到这里面
视图：仅仅负责将模型展示出来
控制器：执行请求、对模型的操作并选择视图展示给用户
