This chapter covers the Spring Framework implementation of the Inversion of Control (IoC) principle. IoC is also known as dependency injection (DI). It is a process whereby objects define their dependencies (that is, the other objects they work with) only through constructor arguments, arguments to a factory method, or properties that are set on the object instance after it is constructed or returned from a factory method. The container then injects those dependencies when it creates the bean. This process is fundamentally the inverse (hence the name, Inversion of Control) of the bean itself controlling the instantiation or location of its dependencies by using direct construction of classes or a mechanism such as the Service Locator pattern.
本章介绍了控制反转（IoC）原理的Spring框架实现。 IoC也称为依赖注入（DI）。在此过程中，对象仅通过构造函数参数，工厂方法的参数或在构造或从工厂方法返回后在对象实例上设置的属性来定义其依赖项（即，与它们一起使用的其他对象）。然后，容器在创建bean时注入那些依赖项。此过程从根本上讲是通过使用类的直接构造或诸如服务定位器模式之类的方法来控制其依赖项的实例化或位置的bean本身的逆过程（因此称为Control Inversion）。
The org.springframework.beans and org.springframework.context packages are the basis for Spring Framework’s IoC container. The BeanFactory interface provides an advanced configuration mechanism capable of managing any type of object.ApplicationContext is a sub-interface of BeanFactory. It adds:
org.springframework.beans 和 org.springframework.context 包是Spring Framework的IoC容器的基础。 BeanFactory接口提供了一种能够管理任何类型对象的高级配置机制。 ApplicationContext是BeanFactory的一个子接口。 它增加了:
- easier integration with Spring’s AOP features;
- 与Spring的AOP功能轻松集成
- Message resource handling (for use in internationalization);
- 消息资源处理（用于国际化）;
- Event publication;
- 活动发布
Application-layer specific contexts such as the WebApplicationContext for use in web applications.
应用层特定的上下文，例如Web应用程序中使用的WebApplicationContext。
In short, the BeanFactory provides the configuration framework and basic functionality, and the ApplicationContext adds more enterprise-specific functionality. The ApplicationContext is a complete superset of the BeanFactory, and is used exclusively in this chapter in descriptions of Spring’s IoC container. For more information on using the BeanFactory instead of the ApplicationContext, refer to The BeanFactory.
简而言之，BeanFactory提供了配置框架和基本功能，而ApplicationContext添加了更多的企业特定功能。 ApplicationContext是BeanFactory的一个完整的超集，在本章中专门用于描述Spring的IoC容器。 有关使用BeanFactory而不是ApplicationContext的更多信息，请参阅BeanFactory。
In Spring, the objects that form the backbone of your application and that are managed by the Spring IoC container are called beans. A bean is an object that is instantiated, assembled, and otherwise managed by a Spring IoC container. Otherwise, a bean is simply one of many objects in your application. Beans, and the dependencies among them, are reflected in the configuration metadata used by a container.
在Spring中，构成应用程序主干并由Spring IoC容器管理的对象称为bean。Bean是由Spring IoC容器实例化，组装和以其他方式管理的对象。否则，bean仅仅是应用程序中许多对象之一。Bean及其之间的依赖关系反映在容器使用的配置元数据中
