Explain various flower activities injected by @ import in spring annotation in detail

Today, let's share the injection form of @ import involved in pig4cloud. Through different forms of injection, the architecture is concise to the greatest extent.

@Import imports a component

Look at the annotation enablepigxdynamicroute. When we need to start the dynamic data source, we just need to add this annotation to the main method.

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@Import(DynamicRouteAutoConfiguration.class)
public @interface EnablePigxDynamicRoute {
}

The actual core is to introduce the configuration class dynamicrouteautoconfiguration, which is not managed by spring scanning

Write a simple example

public class Dog {
}

@Import({Dog.class})
@SpringBootApplication
public class SpringLearnApplication {

  public static void main(String[] args) {
    ConfigurableApplicationContext context = SpringApplication.run(SpringLearnApplication.class,args);
    Assert.isTrue(context.containsBean("com.pig4cloud.spring.learn.demo1.Dog"),"error dog bean");
  }
}

Note that dog does not add the above declarative annotation, but injects a bean with full type name

Importselector interface

As the name implies, when the class introduced by @ import is the implementation of the importselector interface, matching injection will be carried out according to this selector

public class DogImportSelector implements ImportSelector {
  @Override
  public String[] selectImports(AnnotationMetadata importingClassMetadata) {
    ... 匹配逻辑查询出来一堆要注入的全类名
    return new String[]{"com.pig4cloud.spring.learn.demo1.Dog"};
  }
}

@Import({DogImportSelector.class})
@SpringBootApplication
public class SpringLearnApplication {

  public static void main(String[] args) {
    ConfigurableApplicationContext context = SpringApplication.run(SpringLearnApplication.class,"error dog bean");
  }
}

ImportBeanDeFinitionRegistrar

When @ import introduces the importbeandefinitionregister interface implementation class, it will automatically introduce the bean defined by registerbeandeffinitions

According to the resource server configuration settings of pig, a class of pigxresourceserverconfigueradapter is automatically introduced, and the bean name is resourceserverconfigureradapter

public class PigxSecurityBeanDeFinitionRegistrar implements ImportBeanDeFinitionRegistrar {

  @Override
  public void registerBeanDeFinitions(AnnotationMetadata Metadata,BeanDeFinitionRegistry registry) {
    GenericBeanDeFinition beanDeFinition = new GenericBeanDeFinition();
    beanDeFinition.setBeanClass(PigxResourceServerConfigurerAdapter.class);
    registry.registerBeanDeFinition(SecurityConstants.RESOURCE_SERVER_CONfigURER,beanDeFinition);

  }
}

This means that if you use the enablepigxresourceserver annotation, you can open the OAuth resource client operation class encapsulated in pig4cloud, which is also the entry of the source code

@Import({PigxSecurityBeanDeFinitionRegistrar.class})
public @interface EnablePigxResourceServer {

}

The above is the whole content of this article. I hope it will help you in your study, and I hope you will support us a lot.