java 以编程方式设置特定的 bean 对象 - Spring DI
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Programmatically set a specific bean object - Spring DI
提问by Itay Maman
In my program I need to programmatically configure an ApplicationContext. Specifically, I have a reference to an instance of MyClass and I want to define it as a new bean called "xxyy".
在我的程序中，我需要以编程方式配置一个 ApplicationContext。具体来说，我有一个对 MyClass 实例的引用，我想将它定义为一个名为“xxyy”的新 bean。
public void f(MyClass mc, ApplicationContext ac) {
// define mc as the "xxyy" bean on ac ???
...
...
// Now retrieve that bean
MyClass bean = (MyClass) ac.getBean("xxyy");
// It should be the exact same object as mc
Assert.assertSame(mc, bean);
}
The BeanDefinition API let's me specify the class of the new bean, so it does not work for me since I want to specify the instance. I managed to find a solution but it took two additional factory beans which seems like too much code for such an eartly purpose.
BeanDefinition API 让我指定新 bean 的类，所以它对我不起作用，因为我想指定实例。我设法找到了一个解决方案，但它使用了两个额外的工厂 bean，对于这样一个早期的目的来说，这似乎是太多的代码。
Is there a standard API that addresses my needs?
是否有满足我需求的标准 API？
回答by silmx
you can use this context:
你可以使用这个上下文：
GenericApplicationContext mockContext = new GenericApplicationContext();
which has a
其中有一个
mockContext.getBeanFactory().registerSingleton("name", reference);
and plug it in the real context
并将其插入真实上下文中
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
new String[] { "real-context.xml" }, mockContext);
and the classes are:
课程是：
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.context.support.GenericApplicationContext;
回答by skaffman
You need to jump through a few hoops to do this. The first step is to obtain a reference to the context's underlying BeanFactory implementation. This is only possible if your context implements ConfigurableApplicationContext, which most of the standard ones do. You can then register your instance as a singleton in that bean factory:
你需要跳过几圈才能做到这一点。第一步是获取对上下文的底层 BeanFactory 实现的引用。这只有在您的上下文实现 ConfigurableApplicationContext 时才有可能，大多数标准上下文都这样做。然后，您可以在该 bean 工厂中将您的实例注册为单例：
ConfigurableApplicationContext configContext = (ConfigurableApplicationContext)appContext;
SingletonBeanRegistry beanRegistry = configContext.getBeanFactory();
beanRegistry.registerSingleton("xxyy", bean);
You can "insert" any object into the context like this.
您可以像这样将任何对象“插入”到上下文中。
