我问了一个常见的Spring问题:自动转换Spring bean，很多人回答说应该尽可能避免调用Spring的ApplicationContext.getBean()。为什么呢?
我还应该如何访问我配置Spring创建的bean呢?
我在一个非web应用程序中使用Spring，并计划访问LiorH所描述的共享ApplicationContext对象。
修正案
我接受下面的答案，但这里有Martin Fowler的另一种观点，他讨论了依赖注入与使用服务定位器(本质上与调用包装的ApplicationContext.getBean()相同)的优点。
In part, Fowler states, "With service locator the application class asks for it [the service] explicitly by a message to the locator. With injection there is no explicit request, the service appears in the application class - hence the inversion of control.
Inversion of control is a common feature of frameworks, but it's something that comes at a price. It tends to be hard to understand and leads to problems when you are trying to debug. So on the whole I prefer to avoid it [Inversion of Control] unless I need it. This isn't to say it's a bad thing, just that I think it needs to justify itself over the more straightforward alternative."
的确，在application-context.xml中包含该类可以避免使用getBean。然而，即使这样，实际上也是不必要的。如果你正在编写一个独立的应用程序，并且你不想在application-context.xml中包含你的驱动程序类，你可以使用下面的代码让Spring自动装配驱动程序的依赖项:
public class AutowireThisDriver {
private MySpringBean mySpringBean;
public static void main(String[] args) {
AutowireThisDriver atd = new AutowireThisDriver(); //get instance
ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(
"/WEB-INF/applicationContext.xml"); //get Spring context
//the magic: auto-wire the instance with all its dependencies:
ctx.getAutowireCapableBeanFactory().autowireBeanProperties(atd,
AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE, true);
// code that uses mySpringBean ...
mySpringBean.doStuff() // no need to instantiate - thanks to Spring
}
public void setMySpringBean(MySpringBean bean) {
this.mySpringBean = bean;
}
}
当我有一些独立的类需要使用我的应用程序的某些方面(例如测试)时，我需要这样做几次，但我不想将它包含在应用程序上下文中，因为它实际上不是应用程序的一部分。还请注意，这避免了使用字符串名称查找bean的需要，我一直认为这是丑陋的。
