What happens if a bean attempts to load the Spring application context in its constructor?

问题

Given the following Spring application context and class A, what happens when you run class A?

applicationContext.xml (in classpath):

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
    <bean name="a" class="A"/>
</beans>

A.java:

class A {
    private ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");

    public static void main(String[] args) {
        A a = new A();
    }
}

回答1:

Not to question your approach, but why is this necessary? If a bean wants a pointer to the application context it's a part of, it should implement ApplicationContextAware. You'll implement a setter and Spring will inject the app context into the bean.

Unless I'm mistaken, your sample code won't actually give that bean a pointer to its app context, it will start up a new app context using the same XML file as before. This will in turn create a new bean, which will start another app context, etc. — an infinite loop. Try out your code and see whether this happens.

来源：https://stackoverflow.com/questions/2923763/what-happens-if-a-bean-attempts-to-load-the-spring-application-context-in-its-co