Spring之【AnnotatedBeanDefinitionReader】
目录
上一章回顾
前置知识
DefaultListableBeanFactory
beanDefinitionMap属性
beanDefinitionNames属性
registerBeanDefinition(String name, BeanDefinition beanDefinition)方法
AnnotationConfigUtils
部分常量
registerAnnotationConfigProcessors(BeanDefinitionRegistry registry, Object source)方法
BeanDefinitionReaderUtils
registerBeanDefinition(BeanDefinitionHolder definitionHolder, BeanDefinitionRegistry registry)方法
这里先简单说下部分内部组件Bean的作用
ConfigurationClassPostProcessor
AutowiredAnnotationBeanPostProcessor
CommonAnnotationBeanPostProcessor
AnnotatedBeanDefinitionReader
构造器
register(Class... componentClasses)方法
使用AnnotationConfigApplicationContext容器进行测试看下效果
自定义一个组件类
自定义一个实现了BeanDefinitionRegistryPostProcessor的组件类
编写测试类
运行结果
调试程序，看容器中的beanDefinitionMap集合
上一章回顾
主要讲述的是BeanDefinition，意为Bean的定义信息，记录了Bean是否为单例、是否懒加载等信息，Spring先将需要管理的Bean所对应的BeanDefinition信息存储起来，然后再进行后续操作，如：BeanFactoryPostProcessor的实例化和回调、Bean的实例化、BeanPostProcessor的before方法回调、Bean的初始化、BeanPostProcessor的after方法回调等。
前置知识
DefaultListableBeanFactory
beanDefinitionMap属性
// 用于存放容器中的Bean定义信息
// key：beanName
// value：BeanDefinition对象
private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<>(256);beanDefinitionNames属性
// bean名字的集合
private volatile List<String> beanDefinitionNames = new ArrayList<>(256);registerBeanDefinition(String name, BeanDefinition beanDefinition)方法
/*** 对BeanDefinitionRegistry接口中的registerBeanDefinition方法的实现*/
@Override
public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)throws BeanDefinitionStoreException {// ...// 往容器中添加BeanDefinition信息this.beanDefinitionMap.put(beanName, beanDefinition);this.beanDefinitionNames.add(beanName);// ...
}AnnotationConfigUtils
部分常量
// 容器内部组件Bean：ConfigurationClassPostProcessor的beanName
public static final String CONFIGURATION_ANNOTATION_PROCESSOR_BEAN_NAME ="org.springframework.context.annotation.internalConfigurationAnnotationProcessor";// 容器内部组件Bean：AutowiredAnnotationBeanPostProcessor的beanName
public static final String AUTOWIRED_ANNOTATION_PROCESSOR_BEAN_NAME ="org.springframework.context.annotation.internalAutowiredAnnotationProcessor";// 容器内部组件Bean：CommonAnnotationBeanPostProcessor的beanName
public static final String COMMON_ANNOTATION_PROCESSOR_BEAN_NAME ="org.springframework.context.annotation.internalCommonAnnotationProcessor";// 容器内部组件Bean：EventListenerMethodProcessor的beanName
public static final String EVENT_LISTENER_PROCESSOR_BEAN_NAME ="org.springframework.context.event.internalEventListenerProcessor";// 容器内部组件Bean：DefaultEventListenerFactory的beanName
public static final String EVENT_LISTENER_FACTORY_BEAN_NAME ="org.springframework.context.event.internalEventListenerFactory";registerAnnotationConfigProcessors(BeanDefinitionRegistry registry, Object source)方法
public static Set<BeanDefinitionHolder> registerAnnotationConfigProcessors(BeanDefinitionRegistry registry, @Nullable Object source) {// 获取DefaultListableBeanFactory对象DefaultListableBeanFactory beanFactory = unwrapDefaultListableBeanFactory(registry);Set<BeanDefinitionHolder> beanDefs = new LinkedHashSet<>(8);// 添加ConfigurationClassPostProcessor组件Bean的RootBeanDefinition到容器中if (!registry.containsBeanDefinition(CONFIGURATION_ANNOTATION_PROCESSOR_BEAN_NAME)) {RootBeanDefinition def = new RootBeanDefinition(ConfigurationClassPostProcessor.class);def.setSource(source);beanDefs.add(registerPostProcessor(registry, def, CONFIGURATION_ANNOTATION_PROCESSOR_BEAN_NAME));}// 添加AutowiredAnnotationBeanPostProcessor组件Bean的RootBeanDefinition到容器中if (!registry.containsBeanDefinition(AUTOWIRED_ANNOTATION_PROCESSOR_BEAN_NAME)) {RootBeanDefinition def = new RootBeanDefinition(AutowiredAnnotationBeanPostProcessor.class);def.setSource(source);beanDefs.add(registerPostProcessor(registry, def, AUTOWIRED_ANNOTATION_PROCESSOR_BEAN_NAME));}// 添加CommonAnnotationBeanPostProcessor组件Bean的RootBeanDefinition到容器中if (jsr250Present && !registry.containsBeanDefinition(COMMON_ANNOTATION_PROCESSOR_BEAN_NAME)) {RootBeanDefinition def = new RootBeanDefinition(CommonAnnotationBeanPostProcessor.class);def.setSource(source);beanDefs.add(registerPostProcessor(registry, def, COMMON_ANNOTATION_PROCESSOR_BEAN_NAME));}// 添加EventListenerMethodProcessor组件Bean的RootBeanDefinition到容器中if (!registry.containsBeanDefinition(EVENT_LISTENER_PROCESSOR_BEAN_NAME)) {RootBeanDefinition def = new RootBeanDefinition(EventListenerMethodProcessor.class);def.setSource(source);beanDefs.add(registerPostProcessor(registry, def, EVENT_LISTENER_PROCESSOR_BEAN_NAME));}// 添加DefaultEventListenerFactory组件Bean的RootBeanDefinition到容器中if (!registry.containsBeanDefinition(EVENT_LISTENER_FACTORY_BEAN_NAME)) {RootBeanDefinition def = new RootBeanDefinition(DefaultEventListenerFactory.class);def.setSource(source);beanDefs.add(registerPostProcessor(registry, def, EVENT_LISTENER_FACTORY_BEAN_NAME));}return beanDefs;
}// 这里的registry是DefaultListableBeanFactory
private static BeanDefinitionHolder registerPostProcessor(BeanDefinitionRegistry registry, RootBeanDefinition definition, String beanName) {// ...// 将BeanDefinition添加到容器中，也就是DefaultListableBeanFactory的beanDefinitionMap集合中registry.registerBeanDefinition(beanName, definition);// ...
}BeanDefinitionReaderUtils
registerBeanDefinition(BeanDefinitionHolder definitionHolder, BeanDefinitionRegistry registry)方法
public abstract class BeanDefinitionReaderUtils {// ...public static void registerBeanDefinition(BeanDefinitionHolder definitionHolder, BeanDefinitionRegistry registry)throws BeanDefinitionStoreException {// 获取beanNameString beanName = definitionHolder.getBeanName();// 将BeanDefinition添加到Spring容器中registry.registerBeanDefinition(beanName, definitionHolder.getBeanDefinition());// 处理bean的别名String[] aliases = definitionHolder.getAliases();if (aliases != null) {for (String alias : aliases) {registry.registerAlias(beanName, alias);}}}// ...
}这里先简单说下部分内部组件Bean的作用
ConfigurationClassPostProcessor
- 识别@ComponentScan注解
- 识别@Component注解
- 识别@Configuration注解
- 识别@Bean注解
- 识别@Import注解
- ......
AutowiredAnnotationBeanPostProcessor
- 识别@Autowired注解
- 识别@Value注解
- ......
CommonAnnotationBeanPostProcessor
- 识别@Resource注解
- 识别@PostConstruct注解
- 识别@PreDestroy注解
- ......
AnnotatedBeanDefinitionReader
构造器
public class AnnotatedBeanDefinitionReader {// ...// 参数可以理解为Spring容器public AnnotatedBeanDefinitionReader(BeanDefinitionRegistry registry) {// 调用两个参数的构造器this(registry, getOrCreateEnvironment(registry));}public AnnotatedBeanDefinitionReader(BeanDefinitionRegistry registry, Environment environment) {// ...// 前置知识中提到的工具类AnnotationConfigUtils.registerAnnotationConfigProcessors(this.registry);}// ...
}public abstract class AnnotationConfigUtils {// ...public static void registerAnnotationConfigProcessors(BeanDefinitionRegistry registry) {// 这里调用的是前置知识中提到的AnnotationConfigUtils类的方法// 将Spring内部需要的组件Bean的BeanDefinition信息存放到BeanDefinitionMap集合中registerAnnotationConfigProcessors(registry, null);}// ...
}register(Class<?>... componentClasses)方法
public class AnnotatedBeanDefinitionReader {// ...// 可以传入多个用户定义的组件类public void register(Class<?>... componentClasses) {// 遍历传入的组件类for (Class<?> componentClass : componentClasses) {registerBean(componentClass);}}public void registerBean(Class<?> beanClass) {doRegisterBean(beanClass, null, null, null, null);}private <T> void doRegisterBean(Class<T> beanClass, @Nullable String name,@Nullable Class<? extends Annotation>[] qualifiers, @Nullable Supplier<T> supplier,@Nullable BeanDefinitionCustomizer[] customizers) {// 用户自定义的组件类对应创建AnnotatedGenericBeanDefinition对象AnnotatedGenericBeanDefinition abd = new AnnotatedGenericBeanDefinition(beanClass);// ...BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(abd, beanName);definitionHolder = AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry);// 使用前置知识中介绍的工具类添加BeanDefinition到Spring容器中BeanDefinitionReaderUtils.registerBeanDefinition(definitionHolder, this.registry);}// ...
}使用AnnotationConfigApplicationContext容器进行测试看下效果
自定义一个组件类
package bean.definition.test;import org.springframework.context.annotation.ComponentScan;/*** 自定义的组件类，添加了@ComponentScan注解*/
@ComponentScan("bean.definition.test")
public class CustomComponent {
}自定义一个实现了BeanDefinitionRegistryPostProcessor的组件类
package bean.definition.test;import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.stereotype.Component;@Component
public class CustomBeanDefinitionRegistryPostProcessor implements BeanDefinitionRegistryPostProcessor {@Overridepublic void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {// 从容器中获取所有的BeanDefinition的beanNameString[] beanDefinitionNames = registry.getBeanDefinitionNames();// 遍历查看for (String beanDefinitionName : beanDefinitionNames) {System.out.println(beanDefinitionName);}}@Overridepublic void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {}
}
编写测试类
package bean.definition.test;import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class SpringBeanDefinitionTest {public static void main(String[] args) {// 1、执行AnnotatedBeanDefinitionReader实例化// 2、执行ClassPathBeanDefinitionScanner实例化// 3、调用AnnotatedBeanDefinitionReader的register方法将传入的组件类的Bean定义对象添加到容器中// 4、执行AbstractApplicationContext的refresh方法new AnnotationConfigApplicationContext(CustomComponent.class);}
}
运行结果
// 5个Spring内部组件beanName(internal)
org.springframework.context.annotation.internalConfigurationAnnotationProcessor
org.springframework.context.annotation.internalAutowiredAnnotationProcessor
org.springframework.context.annotation.internalCommonAnnotationProcessor
org.springframework.context.event.internalEventListenerProcessor
org.springframework.context.event.internalEventListenerFactory// 2个用户自定义组件beanName
customComponent
customBeanDefinitionRegistryPostProcessor调试程序，看容器中的beanDefinitionMap集合
