一 注册xml配置解析函数

public void init() {
        registerBeanDefinitionParser("application", new DubboBeanDefinitionParser(ApplicationConfig.class, true));
        registerBeanDefinitionParser("module", new DubboBeanDefinitionParser(ModuleConfig.class, true));
        registerBeanDefinitionParser("registry", new DubboBeanDefinitionParser(RegistryConfig.class, true));
        registerBeanDefinitionParser("monitor", new DubboBeanDefinitionParser(MonitorConfig.class, true));
        registerBeanDefinitionParser("provider", new DubboBeanDefinitionParser(ProviderConfig.class, true));
        registerBeanDefinitionParser("consumer", new DubboBeanDefinitionParser(ConsumerConfig.class, true));
        registerBeanDefinitionParser("protocol", new DubboBeanDefinitionParser(ProtocolConfig.class, true));
        registerBeanDefinitionParser("service", new DubboBeanDefinitionParser(ServiceBean.class, true));
        registerBeanDefinitionParser("reference", new DubboBeanDefinitionParser(ReferenceBean.class, false));
        registerBeanDefinitionParser("annotation", new AnnotationBeanDefinitionParser());
    }

二 DubboBeanDefinitionParser

配置解析.png

三 AnnotationBeanDefinitionParser

启动注解支持

• package配置指定扫描包，支持逗号分割多个包路径
• 返回service注解处理bean：ServiceAnnotationBeanPostProcessor
• 注册referenct注解处理bean：ReferenceAnnotationBeanPostProcessor

protected void doParse(Element element, ParserContext parserContext, BeanDefinitionBuilder builder) {

        String packageToScan = element.getAttribute("package");

        String[] packagesToScan = trimArrayElements(commaDelimitedListToStringArray(packageToScan));

        builder.addConstructorArgValue(packagesToScan);

        builder.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);

        // Registers ReferenceAnnotationBeanPostProcessor
        registerReferenceAnnotationBeanPostProcessor(parserContext.getRegistry());

    }

3.1 ServiceAnnotationBeanPostProcessor

• 实现预处理接口
  BeanDefinitionRegistryPostProcessor.postProcessBeanDefinitionRegistry
• 对目标包，扫描Service注解的类

DubboClassPathBeanDefinitionScanner scanner =
                new DubboClassPathBeanDefinitionScanner(registry, environment, resourceLoader);
        BeanNameGenerator beanNameGenerator = resolveBeanNameGenerator(registry);
        scanner.setBeanNameGenerator(beanNameGenerator);
        scanner.addIncludeFilter(new AnnotationTypeFilter(Service.class));

• 获取注解内容，解析接口类
• 注册service

private void registerServiceBean(BeanDefinitionHolder beanDefinitionHolder, BeanDefinitionRegistry registry,
                                     DubboClassPathBeanDefinitionScanner scanner) {

        Class<?> beanClass = resolveClass(beanDefinitionHolder);

        Service service = findAnnotation(beanClass, Service.class);

        Class<?> interfaceClass = resolveServiceInterfaceClass(beanClass, service);

        String annotatedServiceBeanName = beanDefinitionHolder.getBeanName();

        AbstractBeanDefinition serviceBeanDefinition =
                buildServiceBeanDefinition(service, interfaceClass, annotatedServiceBeanName);

        // ServiceBean Bean name
        String beanName = generateServiceBeanName(service, interfaceClass, annotatedServiceBeanName);

        if (scanner.checkCandidate(beanName, serviceBeanDefinition)) { // check duplicated candidate bean
            registry.registerBeanDefinition(beanName, serviceBeanDefinition);
        }
    }

3.2 ReferenceAnnotationBeanPostProcessor

• 实现接口postProcessPropertyValues，注入reference接口
• 基于注解配置创建ReferenctBean
• 返回bean代理，注入到目标属性

protected Object doGetInjectedBean(Reference reference, Object bean, String beanName, Class<?> injectedType,
                                       InjectionMetadata.InjectedElement injectedElement) throws Exception {

        String referencedBeanName = buildReferencedBeanName(reference, injectedType);

        ReferenceBean referenceBean = buildReferenceBeanIfAbsent(referencedBeanName, reference, injectedType, getClassLoader());

        cacheInjectedReferenceBean(referenceBean, injectedElement);

        Object proxy = buildProxy(referencedBeanName, referenceBean, injectedType);

        return proxy;
    }