我还没有找到我能够理解的Spring bean的高级定义。我经常在Grails文档和书籍中看到它们,但我认为了解它们是什么将是有益的。那么春豆是什么呢?如何使用它们?它们与依赖注入有关吗?


当前回答

在Spring中,那些构成应用程序主干并由Spring IoC管理的对象 容器被称为bean。bean只是一个实例化、组装等的对象 由Spring IoC容器管理;

其他回答

Spring beans are just object instances that are managed by the Spring IOC container. Spring IOC container carry the Bag of Bean.Bean creation,maintain and deletion are the responsibilities of Spring Container. We can put the bean in to Spring by Wiring and Auto Wiring. Wiring mean we manually configure it into the XML file. Auto Wiring mean we put the annotations in the Java file then Spring automatically scan the root-context where java configuration file, make it and put into the bag of Spring.

你只理解了一部分。您必须根据需要定制bean,并通知Spring容器在需要时管理它,方法是使用Martin Fowler创造的通常称为IoC(控制反转)的方法,也称为依赖注入(DI)。

您以某种方式连接bean,这样您就不必关心实例化或计算bean上的任何依赖项。这就是众所周知的好莱坞原则。

谷歌是最好的工具,除了在这个问题中你会被淹没的链接之外,还可以探索更多关于这个问题的内容。:)

For a Java class to be usable as a Java bean, its setter- and getter-method names need to be as per the JavaBean guidelines (also called design patterns) for properties. If such a Java class is instantiable & manageable by the Spring IoC container, it is a Spring bean. To achieve this, the programmer wires the class as a bean definition of a suitable scope by using XML config files or annotations or a mix of both. The programmer can create new Spring beans out of existing Spring beans by wiring further by passing the latter to constructor-arguments of the former either as string-names as <idref> elements or by dependency injection (it can be recursive).

这个答案可以与我的这个SO答案一起阅读,以获得更多的背景信息。

春天有IoC容器,里面装着一袋豆子;创建、维护和删除是Spring Container的职责。 我们可以通过布线和自动布线将bean放到Spring中。 “连线”意味着我们手动将其配置到XML文件中,“自动连线”意味着我们将注释放入Java文件中,然后Spring自动扫描Java配置文件所在的根上下文,将其制作并放入Spring的包中。

这里是详细的URI,您可以从中获得有关bean的更多信息

Spring beans are classes. Instead of instantiating a class (using new), you get an instance as a bean cast to your class type from the application context, where the bean is what you configured in the application context configuration. This way, the whole application maintains singleton-scope instance throughout the application. All beans are initialized following their configuration order right after the application context is instantiated. Even if you don't get any beans in your application, all beans instances are already created the moment after you created the application context.