spring注解@Import用法详解

//自定义逻辑返回需要导入的组件
public class MyImportSelector implements ImportSelector {
  // 返回值就是导入到容器中的组件全类名
  // AnnotationMetadata：当前标注@Import注解的类的所有注解信息
  public String[] selectImports(AnnotationMetadata importingClassMetadata) {
    return new String[] { "test.spring.ZhangSan", "test.spring.LiSi", "test.spring.WangWu" };
  }
}

public class MyBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {
  /**
   * @param annotationMetadata 当前标注@Import注解的类的所有注解信息
   * @param beanDefinitionRegistry BeanDefinition的注册类
   */
  public void registerBeanDefinitions(AnnotationMetadata annotationMetadata, BeanDefinitionRegistry beanDefinitionRegistry) {
    RootBeanDefinition beanDefinition = new RootBeanDefinition(Cat.class);
    beanDefinitionRegistry.registerBeanDefinition("cat",beanDefinition);
  }
}

@Configuration
@Import(value = {MyBeanDefinitionRegistrar.class})
public class MyConfig {
}

/**测试结果
beanName: org.springframework.context.annotation.internalConfigurationAnnotationProcessor
beanName: org.springframework.context.annotation.internalAutowiredAnnotationProcessor
beanName: org.springframework.context.annotation.internalCommonAnnotationProcessor
beanName: org.springframework.context.event.internalEventListenerProcessor
beanName: org.springframework.context.event.internalEventListenerFactory
beanName: myConfig
beanName: cat
*/