10、组件注册-@Import-使用ImportBeanDefinitionRegistrar
public interface ImportBeanDefinitionRegistrar {
/**
* Register bean definitions as necessary based on the given annotation metadata of
* the importing {@code @Configuration} class.
* <p>Note that {@link BeanDefinitionRegistryPostProcessor} types may <em>not</em> be
* registered here, due to lifecycle constraints related to {@code @Configuration}
* class processing.
* @param importingClassMetadata annotation metadata of the importing class
* @param registry current bean definition registry
*/
public void registerBeanDefinitions(
AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry);
}
10.1 实现ImportBeanDefinitionRegistrar 并重写 registerBeanDefinitionsfan方法
package com.hw.springannotation.conditional;
import com.hw.springannotation.beans.RainBow;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.type.AnnotationMetadata;
/**
* @Description TODO
* @Author hw
* @Date 2018/11/28 16:16
* @Version 1.0
*/
public class MyImportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {
/**
* @param importingClassMetadata annotation metadata of the importing class 当前类的注解信息
* @param registry current bean definition registry 定义的注册类
* 所有需要添加到容器中的bean BeanDefinitionRegistry.registerBeanDefinition 手动注册进来
*/
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
boolean red = registry.containsBeanDefinition("com.hw.springannotation.beans.Red");
boolean blue = registry.containsBeanDefinition("com.hw.springannotation.beans.Blue");
if (red && blue) {
// 指定Bean的定义信息，Bean的类型，作用域等
BeanDefinition beanDefinition = new RootBeanDefinition(RainBow.class);
// 注册一个Bean，指定bean名
registry.registerBeanDefinition("rainBow", beanDefinition);
}
}
}
10.2 使用
新建RainBow类，并在MainConfig中导入MyImportBeanDefinitionRegistrar.class
@Import({Color.class, Red.class, MyImportSelector.class, MyImportBeanDefinitionRegistrar.class})
10.3 测试
