springboot~ImportBeanDefinitionRegistrar在自定义RPC框架中的使用

入口注解设计Target(ElementType.TYPE) Retention(RetentionPolicy.RUNTIME) Documented Import(RpcComponentRegistrar.class) public interface EnableRpc { // 扫描的包路径 String[] basePackages() default {}; // 注册中心类型 RegistryType registry() default RegistryType.ZOOKEEPER; // 协议类型 ProtocolType protocol() default ProtocolType.HTTP; }2. RpcComponentRegistrar的多阶段注册public class RpcComponentRegistrar implements ImportBeanDefinitionRegistrar, EnvironmentAware { private Environment environment; Override public void setEnvironment(Environment environment) { this.environment environment; } Override public void registerBeanDefinitions( AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry ) { // 阶段1解析配置 AnnotationAttributes attributes AnnotationAttributes.fromMap( importingClassMetadata.getAnnotationAttributes(EnableRpc.class.getName())); // 阶段2根据配置动态注册核心组件 registerRegistryCenter(registry, attributes); registerProtocolProcessor(registry, attributes); registerLoadBalancer(registry, attributes); // 阶段3扫描并注册服务提供者和消费者 scanAndRegisterServices(registry, attributes); } private void registerRegistryCenter( BeanDefinitionRegistry registry, AnnotationAttributes attributes ) { RegistryType type attributes.getEnum(registry); RootBeanDefinition beanDefinition new RootBeanDefinition(); beanDefinition.setBeanClassName(getRegistryClassByType(type)); // 从Environment读取配置如zookeeper地址 beanDefinition.getPropertyValues().add(address, environment.getProperty(rpc.registry.address)); registry.registerBeanDefinition(rpcRegistryCenter, beanDefinition); } private void scanAndRegisterServices( BeanDefinitionRegistry registry, AnnotationAttributes attributes ) { // 1. 扫描ServiceProvider注解的服务提供者 SetBeanDefinition providers scanForAnnotations( attributes.getStringArray(basePackages), ServiceProvider.class); // 2. 为每个服务提供者注册特殊的BeanDefinition for (BeanDefinition providerDef : providers) { GenericBeanDefinition enhancedDef enhanceForProvider(providerDef); registry.registerBeanDefinition( providerDef.getBeanClassName(), enhancedDef); // 3. 同时自动注册到服务注册中心 registerToServiceDiscovery(providerDef); } // 4. 扫描RpcReference注解的消费方 // 需要创建ReferenceBeanFactoryBean来处理动态代理 registerReferenceProcessor(registry, attributes); } private GenericBeanDefinition enhanceForProvider(BeanDefinition originalDef) { GenericBeanDefinition definition new GenericBeanDefinition(originalDef); // 添加服务暴露的初始化逻辑 definition.setInitMethodName(exportService); // 添加后置处理器来监听服务状态 definition.getPropertyValues().add(serviceRegistry, new RuntimeBeanReference(rpcRegistryCenter)); return definition; } private void registerReferenceProcessor( BeanDefinitionRegistry registry, AnnotationAttributes attributes ) { // 创建处理RpcReference注解的后置处理器 RootBeanDefinition processorDef new RootBeanDefinition( RpcReferenceAnnotationBeanPostProcessor.class); // 注入必要的依赖 processorDef.getPropertyValues().add(registryCenter, new RuntimeBeanReference(rpcRegistryCenter)); processorDef.getPropertyValues().add(loadBalancer, new RuntimeBeanReference(rpcLoadBalancer)); registry.registerBeanDefinition( rpcReferenceAnnotationBeanPostProcessor, processorDef); } }3. RPC框架的关键扩展点设计服务消费者代理工厂public class RpcReferenceFactoryBean implements FactoryBeanObject { private Class? interfaceType; private String serviceName; private LoadBalancer loadBalancer; Override public Object getObject() throws Exception { // 创建动态代理实现RPC调用 return Proxy.newProxyInstance( interfaceType.getClassLoader(), new Class?[] {interfaceType}, new RpcInvocationHandler(serviceName, loadBalancer) ); } Override public Class? getObjectType() { return interfaceType; } }注解处理器public class RpcReferenceAnnotationBeanPostProcessor implements BeanPostProcessor, BeanFactoryAware { Override public Object postProcessAfterInitialization(Object bean, String beanName) { // 扫描bean中所有RpcReference注解的字段 Field[] fields bean.getClass().getDeclaredFields(); for (Field field : fields) { if (field.isAnnotationPresent(RpcReference.class)) { RpcReference reference field.getAnnotation(RpcReference.class); // 为每个引用创建代理并注入 Object proxy createProxy(field.getType(), reference); field.setAccessible(true); try { field.set(bean, proxy); } catch (IllegalAccessException e) { throw new RuntimeException(e); } } } return bean; }