[@Controller]4 详解@ModelAttribute.docxVIP

A、@ModelAttribute Annotation that binds a method parameter or method return value to a named model attribute, exposed to a web view. Supported for RequestMapping annotated handler classes. 在被@RequestMapping注释的处理器类中，这个注释可以绑定一个方法参数或绑定一个方法的返回值到一个命名的模型属性，提供给一个视图。 Can be used to expose command objects to a web view, using specific attribute names, through annotating corresponding parameters of a RequestMapping annotated handler method). 可以用于把一个command对象提供给web视图，使用指定的属性名称，在被@RequestMapping注释的处理器方法中注释相关参数。 Can also be used to expose reference data to a web view through annotating accessor methods in a controller class which is based on RequestMapping annotated handler methods, with such accessor methods allowed to have any arguments that RequestMapping supports for handler methods, returning the model attribute value to expose. 可以用于提供数据给一个web视图，通过注释处理器方法，这个方法允许有任何参数，返回的模型属性值被提供。 A.1、@ ModelAttribute的属性 value The name of the model attribute to bind to. 绑定的模型属性的名称。 The default model attribute name is inferred from the declared attribute type (i.e. the method parameter type or method return type), based on the non-qualified class name: e.g. orderAddress for class mypackage.OrderAddress, or orderAddressList for Listmypackage.OrderAddress. 默认的模型属性名称自动判断声明的属性类型（如，方法参数类型或方法返回类型）。如这个值是orderAddress，就对于当前包. OrderAddress。 B、@ModelAttribute注释一个方法 An @ModelAttribute on a method indicates the purpose of that method is to add one or more model attributes. Such methods support the same argument types as @RequestMapping methods but cannot be mapped directly to requests. Instead @ModelAttribute methods in a controller are invoked before @RequestMapping methods, within the same controller. 被@ModelAttribute注释的方法表示这个方法的目的是增加一个或多个模型(model)属性。这个方法和被@RequestMapping注释的方法一样也支持@RequestParam参数，但是它不能直接被请求映射。实际上，控制器中的@ModelAttribute方法是在同一控制器中的@RequestMapping方法被调用之前调用的。 @ModelAttribute methods are used to populate the model with commonly needed attributes for example to fill a drop-down with states or w