Когда имена компонентов перекрываются, выходные данные журнала различаются в зависимости от типа возвращаемого значения ⇐ JAVA

[Гость]

I learned that if the names of beans registered through component scanning overlap with those registered through configuration methods, overriding occurs.

However, when I mistakenly specified the return type of a method in the configuration as the implementation class instead of the interface during auto-completion, the log related to overriding was not outputted. I'm curious about the reason for this.

This is the code for the interface.

Код: Выделить всё

package hello.core.bean_overriding; public interface BeanInterface { } 

This is the code for the implementation class. Adding the @Component annotation automatically registers it as a bean.

Код: Выделить всё

package hello.core.bean_overriding; import org.springframework.stereotype.Component; @Component  // register bean (name: "beanA") public class BeanA implements BeanInterface {     public BeanA() {         System.out.println("BeanA.BeanA = " + this);     } 

CASE 1: return type of factory method = interface

Код: Выделить всё

@Configuration @ComponentScan(basePackageClasses = BeanOverridingTest.class) static class TestConfiguration{     @Bean     public BeanInterface beanA() {  // register bean (name: "beanA")         return new BeanA();     } } 

In this case, the following overriding-related log is printed. "17:30:59.922 [Test worker] DEBUG o.s.b.f.s.DefaultListableBeanFactory --Overriding bean definition for bean 'beanA' with a different definition: ..."

CASE 2: return type of factory method = implementation class

Код: Выделить всё

@Configuration @ComponentScan(basePackageClasses = BeanOverridingTest.class) static class TestConfiguration{     @Bean     public BeanA beanA() {  // register bean (name: "beanA")         return new BeanA();     } } 

In this case, the overriding-related log is not printed.

Thank you for reading through my question, and I'd be even more grateful if you could give me some advice. Wishing you a great day.


Источник: https://stackoverflow.com/questions/781 ... -type-of-t