ImportBeanDefinitionRegistrar接口

@MapperScan(basePackages = {"com.cnmyhr.ecch.contract.mapper","com.cnmyhr.ecch.event.core.mapper"}) 》

@Import({MapperScannerRegistrar.class})》

public class MapperScannerRegistrar implements ImportBeanDefinitionRegistrar, ResourceLoaderAware {》

》》》
public interface ImportBeanDefinitionRegistrar {
    default void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry, BeanNameGenerator importBeanNameGenerator) {
        this.registerBeanDefinitions(importingClassMetadata, registry);
    }

    default void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
    }
}
重要的是第二个参数

BeanDefinitionRegistry registry

public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
    String name = DependsOnDatabaseInitializationPostProcessor.class.getName();
    if (!registry.containsBeanDefinition(name)) {
        BeanDefinitionBuilder builder = BeanDefinitionBuilder.rootBeanDefinition(DependsOnDatabaseInitializationPostProcessor.class);
        registry.registerBeanDefinition(name, builder.getBeanDefinition());
    }

}