@Component with parent?

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长情又很酷
长情又很酷 2021-02-14 03:04

Is there any way to use with @Component annotation (creating spring beans using annotation)?

I would like to create sprin

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  • 2021-02-14 03:07

    Just came across the same Construct.. (a general abstract parent Class which used Beans - with context.xml-declaration for an potential Implementation that was injected by Component-scan)

    This is what I could have done in the @Component Class:

    @Autowired
    public void setBeanUsedInParent(BeanUsedInParent bean) {
       super.setBeanUsedInParent(bean);
    }
    

    ..what I ended up doing (better, since it makes clear that the injection works on the object not on classes) - and if you are able to modify the parent Class:

    // abstract getter in parent Class
    public abstract BeanUsedInParent getBeanUsedInParent();
    

    ..leave the actual Beans as well as their injection up to the actual implementation (the @Component Class):

    @Autowired
    private BeanUsedInParent beanUsedInParent;
    
    @Override
    public BeanUsedInParent getBeanUsedInParent() {
       return this.beanUsedInParent;
    }
    
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  • 2021-02-14 03:16

    Following my comment, this piece of XML

    <bean id="base" abstract="true">
        <property name="foo" ref="bar"/>
    </bean>
    
    <bean class="Wallace" parent="base"/>
    <bean class="Gromit" parent="base"/>
    

    is more or less eqivalent to this code (note that I created artificial Base class since abstract beans in Spring don't need a class):

    public abstract class Base {
        @Autowired
        protected Foo foo;
    }
    
    @Component
    public class Wallace extends Base {}
    
    @Component
    public class Gromit extends Base {}
    

    Wallace and Gromit now have access to common Foo property. Also you can override it, e.g. in @PostConstruct.

    BTW I really liked parent feature in XML which allowed to keep beans DRY, but Java approach seems even cleaner.

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