Spring与Dubbo整合原理与源码分析
【1】注解@EnableDubbo
@Target({ElementType.TYPE}) @Retention(RetentionPolicy.RUNTIME) @Inherited @Documented @EnableDubboConfig // @EnableDubboConfig注解用来将properties文件中的配置项转化为对应的Bean @DubboComponentScan // @DubboComponentScan注解用来扫描服务提供者和引用者(@Service与@Reference) public @interface EnableDubbo { @AliasFor(annotation = DubboComponentScan.class, attribute = "basePackages") String[] scanBasePackages() default {}; @AliasFor(annotation = DubboComponentScan.class, attribute = "basePackageClasses") Class<?>[] scanBasePackageClasses() default {}; @AliasFor(annotation = EnableDubboConfig.class, attribute = "multiple") boolean multipleConfig() default true; }
【2】注解@EnableDubboConfig
@Target({ElementType.TYPE}) @Retention(RetentionPolicy.RUNTIME) @Inherited @Documented @Import(DubboConfigConfigurationRegistrar.class) public @interface EnableDubboConfig { boolean multiple() default true; }
1）DubboConfigConfigurationRegistrar类的作用
//因为实现了ImportBeanDefinitionRegistrar接口，spring容器就会实例化该类，并且调用其registerBeanDefinitions方法； public class DubboConfigConfigurationRegistrar implements ImportBeanDefinitionRegistrar { @Override public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) { //执行DubboConfigConfigurationRegistrar; AnnotationAttributes attributes = AnnotationAttributes.fromMap( importingClassMetadata.getAnnotationAttributes(EnableDubboConfig.class.getName())); boolean multiple = attributes.getBoolean("multiple"); //默认值是true // Single Config Bindings registerBeans(registry, DubboConfigConfiguration.Single.class); if (multiple) { // Since 2.6.6 https://github.com/apache/dubbo/issues/3193 registerBeans(registry, DubboConfigConfiguration.Multiple.class); } } }
2）registerBeans做了什么
public static void registerBeans(BeanDefinitionRegistry registry, Class<?>... annotatedClasses) { if (ObjectUtils.isEmpty(annotatedClasses)) { return; } ... AnnotatedBeanDefinitionReader reader = new AnnotatedBeanDefinitionReader(registry); ... // 利用Spring中的AnnotatedBeanDefinitionReader来解析annotatedClasses // 会解析该类上的注解，然后进行处理 reader.register(annotatedClasses); }
3）DubboConfigConfiguration类展示
public class DubboConfigConfiguration { /** * Single Dubbo {@link AbstractConfig Config} Bean Binding */ @EnableDubboConfigBindings({ @EnableDubboConfigBinding(prefix = "dubbo.application", type = ApplicationConfig.class), @EnableDubboConfigBinding(prefix = "dubbo.module", type = ModuleConfig.class), @EnableDubboConfigBinding(prefix = "dubbo.registry", type = RegistryConfig.class), @EnableDubboConfigBinding(prefix = "dubbo.protocol", type = ProtocolConfig.class), @EnableDubboConfigBinding(prefix = "dubbo.monitor", type = MonitorConfig.class), @EnableDubboConfigBinding(prefix = "dubbo.provider", type = ProviderConfig.class), @EnableDubboConfigBinding(prefix = "dubbo.consumer", type = ConsumerConfig.class), @EnableDubboConfigBinding(prefix = "dubbo.config-center", type = ConfigCenterBean.class), @EnableDubboConfigBinding(prefix = "dubbo.metadata-report", type = MetadataReportConfig.class), @EnableDubboConfigBinding(prefix = "dubbo.metrics", type = MetricsConfig.class) }) public static class Single {} /** * Multiple Dubbo {@link AbstractConfig Config} Bean Binding */ @EnableDubboConfigBindings({ @EnableDubboConfigBinding(prefix = "dubbo.applications", type = ApplicationConfig.class, multiple = true), @EnableDubboConfigBinding(prefix = "dubbo.modules", type = ModuleConfig.class, multiple = true), @EnableDubboConfigBinding(prefix = "dubbo.registries", type = RegistryConfig.class, multiple = true), @EnableDubboConfigBinding(prefix = "dubbo.protocols", type = ProtocolConfig.class, multiple = true), @EnableDubboConfigBinding(prefix = "dubbo.monitors", type = MonitorConfig.class, multiple = true), @EnableDubboConfigBinding(prefix = "dubbo.providers", type = ProviderConfig.class, multiple = true), @EnableDubboConfigBinding(prefix = "dubbo.consumers", type = ConsumerConfig.class, multiple = true), @EnableDubboConfigBinding(prefix = "dubbo.config-centers", type = ConfigCenterBean.class, multiple = true), @EnableDubboConfigBinding(prefix = "dubbo.metadata-reports", type = MetadataReportConfig.class, multiple = true), @EnableDubboConfigBinding(prefix = "dubbo.metricses", type = MetricsConfig.class, multiple = true) }) public static class Multiple {} }
4）那么必然又会解析到@EnableDubboConfigBindings注解
//又是利用了实现了ImportBeanDefinitionRegistrar接口，在实例化该类会调用其registerBeanDefinitions方法； public class DubboConfigBindingsRegistrar implements ImportBeanDefinitionRegistrar, EnvironmentAware { private ConfigurableEnvironment environment; @Override public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) { //执行DubboConfigBindingsRegistrar AnnotationAttributes attributes = AnnotationAttributes.fromMap(importingClassMetadata.getAnnotationAttributes(EnableDubboConfigBindings.class.getName())); // 拿到多个@EnableDubboConfigBinding注解 AnnotationAttributes[] annotationAttributes = attributes.getAnnotationArray("value"); DubboConfigBindingRegistrar registrar = new DubboConfigBindingRegistrar(); //将环境变量注入 registrar.setEnvironment(environment); for (AnnotationAttributes element : annotationAttributes) { // 逐个解析@EnableDubboConfigBinding注解，比如@EnableDubboConfigBinding(prefix = "dubbo.application", type = ApplicationConfig.class) registrar.registerBeanDefinitions(element, registry); } } @Override public void setEnvironment(Environment environment) { Assert.isInstanceOf(ConfigurableEnvironment.class, environment); this.environment = (ConfigurableEnvironment) environment; } }
5）registrar.registerBeanDefinitions方法的调用情况
public class DubboConfigBindingRegistrar implements ImportBeanDefinitionRegistrar, EnvironmentAware { private final Log log = LogFactory.getLog(getClass()); private ConfigurableEnvironment environment; @Override public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) { //执行DubboConfigBindingRegistrar AnnotationAttributes attributes = AnnotationAttributes.fromMap(importingClassMetadata.getAnnotationAttributes(EnableDubboConfigBinding.class.getName())); registerBeanDefinitions(attributes, registry); } protected void registerBeanDefinitions(AnnotationAttributes attributes, BeanDefinitionRegistry registry) { // prefix = "dubbo.application" String prefix = environment.resolvePlaceholders(attributes.getString("prefix")); // type = ApplicationConfig.class Class<? extends AbstractConfig> configClass = attributes.getClass("type"); boolean multiple = attributes.getBoolean("multiple"); //针对配置分别进行注册成Bean对象，方法1 registerDubboConfigBeans(prefix, configClass, multiple, registry); } //方法1，因为Single和Multiple都是走同一套逻辑，采用参数boolean multiple区分 private void registerDubboConfigBeans(String prefix, Class<? extends AbstractConfig> configClass, boolean multiple, BeanDefinitionRegistry registry) { // 从properties文件中根据前缀拿对应的配置项，比如根据dubbo.application前缀， // 就可以拿到如下配置： // dubbo.application.name=dubbo-demo-provider-application // dubbo.application.logger=log4j Map<String, Object> properties = getSubProperties(environment.getPropertySources(), prefix); // 如果没有相关的配置项，则不需要注册BeanDefinition if (CollectionUtils.isEmpty(properties)) { if (log.isDebugEnabled()) { log.debug(...); } return; } // 根据配置项生成beanNames，为什么会有多个？ // 普通情况一个dubbo.application前缀对应一个ApplicationConfig类型的Bean // 特殊情况下（配置两种协议），比如dubbo.protocols对应了： // dubbo.protocols.p1.name=dubbo // dubbo.protocols.p1.port=20880 // dubbo.protocols.p1.host=0.0.0.0 // dubbo.protocols.p2.name=http // dubbo.protocols.p2.port=8082 // dubbo.protocols.p2.host=0.0.0.0 // 那么就需要对应两个ProtocolConfig类型的Bean，那么就需要两个beanName:p1和p2 // 这里就是multiple为true或false的区别，名字的区别，根据multiple用来判断是否从配置项中获取beanName // 如果multiple为false，则看有没有配置id属性，如果没有配置则自动生成一个beanName. Set<String> beanNames = multiple ? resolveMultipleBeanNames(properties) : Collections.singleton(resolveSingleBeanName(properties, configClass, registry)); for (String beanName : beanNames) { // 为每个beanName,注册一个空的BeanDefinition，方法2 registerDubboConfigBean(beanName, configClass, registry); // 为每个bean注册一个DubboConfigBindingBeanPostProcessor的Bean后置处理器，方法3 //这里存在的问题就是对应每一种配置都会产生对应的BeanPostProcessor，最多好像也就是10种左右 //但其实一个就可以做的任务，拓展成多个貌似不太合理，结合处理逻辑都是同一套就很尴尬 registerDubboConfigBindingBeanPostProcessor(prefix, beanName, multiple, registry); } // 注册一个NamePropertyDefaultValueDubboConfigBeanCustomizer的bean registerDubboConfigBeanCustomizers(registry); } //方法2，为对应的配置生成一个beanDefinition，并注入到容器 private void registerDubboConfigBean(String beanName, Class<? extends AbstractConfig> configClass,BeanDefinitionRegistry registry) { BeanDefinitionBuilder builder = rootBeanDefinition(configClass); AbstractBeanDefinition beanDefinition = builder.getBeanDefinition(); registry.registerBeanDefinition(beanName, beanDefinition); // ApplicatinoConfig对象 if (log.isInfoEnabled()) { log.info("...); //日志记录 } } //方法3 private void registerDubboConfigBindingBeanPostProcessor(String prefix, String beanName, boolean multiple,BeanDefinitionRegistry registry) { // 注册一个DubboConfigBindingBeanPostProcessor的Bean // 每个XxConfig的Bean对应一个DubboConfigBindingBeanPostProcessor的Bean // 比如，一个ApplicationConfig对应一个DubboConfigBindingBeanPostProcessor， // 一个ProtocolConfig也会对应一个DubboConfigBindingBeanPostProcessor // 在构造DubboConfigBindingBeanPostProcessor的时候会指定构造方法的值，这样就可以区别开来了 Class<?> processorClass = DubboConfigBindingBeanPostProcessor.class; BeanDefinitionBuilder builder = rootBeanDefinition(processorClass); // 真实的前缀，比如dubbo.registries.r2 String actualPrefix = multiple ? normalizePrefix(prefix) + beanName : prefix; // 添加两个构造方法参数值，所以会调用DubboConfigBindingBeanPostProcessor的两个参数的构造方法 builder.addConstructorArgValue(actualPrefix).addConstructorArgValue(beanName); AbstractBeanDefinition beanDefinition = builder.getBeanDefinition(); beanDefinition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE); registerWithGeneratedName(beanDefinition, registry); if (log.isInfoEnabled()) { log.info(...); } } private void registerDubboConfigBeanCustomizers(BeanDefinitionRegistry registry) { registerInfrastructureBean(registry, BEAN_NAME, NamePropertyDefaultValueDubboConfigBeanCustomizer.class); } @Override public void setEnvironment(Environment environment) { Assert.isInstanceOf(ConfigurableEnvironment.class, environment); this.environment = (ConfigurableEnvironment) environment; } private Set<String> resolveMultipleBeanNames(Map<String, Object> properties) { Set<String> beanNames = new LinkedHashSet<String>(); // 比如dubbo.protocols.p1.name=dubbo的propertyName为p1.name for (String propertyName : properties.keySet()) { // propertyName为p1.name int index = propertyName.indexOf("."); if (index > 0) { // 截取beanName名字为p1 String beanName = propertyName.substring(0, index); beanNames.add(beanName); } } return beanNames; } private String resolveSingleBeanName(Map<String, Object> properties, Class<? extends AbstractConfig> configClass,BeanDefinitionRegistry registry) { // 配置了dubbo.application.id=appl，那么appl就是beanName String beanName = (String) properties.get("id"); // 如果beanName为null，则会进入if分支，由spring自动生成一个beanName,比如org.apache.dubbo.config.ApplicationConfig#0 if (!StringUtils.hasText(beanName)) { BeanDefinitionBuilder builder = rootBeanDefinition(configClass); beanName = BeanDefinitionReaderUtils.generateBeanName(builder.getRawBeanDefinition(), registry); } return beanName; } }
6）单个DubboConfigBindingBeanPostProcessor的展示（删减掉部分不怎么用到的）
public class DubboConfigBindingBeanPostProcessor implements BeanPostProcessor, ApplicationContextAware, InitializingBean, BeanDefinitionRegistryPostProcessor { private final String prefix; private final String beanName; private DubboConfigBinder dubboConfigBinder; .... private List<DubboConfigBeanCustomizer> configBeanCustomizers = Collections.emptyList(); .... @Override public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { // 每个XxConfig对应一个BeanPostProcessor，所以每个DubboConfigBindingBeanPostProcessor只处理对应的beanName if (this.beanName.equals(beanName) && bean instanceof AbstractConfig) { AbstractConfig dubboConfig = (AbstractConfig) bean; // 从properties文件中获取值，并设置到dubboConfig对象中 bind(prefix, dubboConfig); // 设置dubboConfig对象的name属性，设置为beanName customize(beanName, dubboConfig); } return bean; } private void bind(String prefix, AbstractConfig dubboConfig) { dubboConfigBinder.bind(prefix, dubboConfig); if (log.isInfoEnabled()) { log.info(...); } } private void customize(String beanName, AbstractConfig dubboConfig) { for (DubboConfigBeanCustomizer customizer : configBeanCustomizers) { customizer.customize(beanName, dubboConfig); } } ... @Override public void afterPropertiesSet() throws Exception { initDubboConfigBinder(); // 创建DefaultDubboConfigBinder initConfigBeanCustomizers(); } private void initDubboConfigBinder() { if (dubboConfigBinder == null) { try { // 先从Spring容器中获取DubboConfigBinder，默认获取不到 dubboConfigBinder = applicationContext.getBean(DubboConfigBinder.class); } catch (BeansException ignored) { if (log.isDebugEnabled()) { log.debug("DubboConfigBinder Bean can't be found in ApplicationContext."); } // Use Default implementation // 生成一个默认的 dubboConfigBinder = createDubboConfigBinder(applicationContext.getEnvironment()); } } dubboConfigBinder.setIgnoreUnknownFields(ignoreUnknownFields); dubboConfigBinder.setIgnoreInvalidFields(ignoreInvalidFields); } private void initConfigBeanCustomizers() { // 得到之前创建了的NamePropertyDefaultValueDubboConfigBeanCustomizer Collection<DubboConfigBeanCustomizer> configBeanCustomizers = beansOfTypeIncludingAncestors(applicationContext, DubboConfigBeanCustomizer.class).values(); this.configBeanCustomizers = new ArrayList<>(configBeanCustomizers); AnnotationAwareOrderComparator.sort(this.configBeanCustomizers); } ... }
【3】注解@DubboComponentScan
@Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Import(DubboComponentScanRegistrar.class) public @interface DubboComponentScan { String[] value() default {}; String[] basePackages() default {}; Class<?>[] basePackageClasses() default {}; }
1）导入的DubboComponentScanRegistrar类做了什么
/又是利用了实现了ImportBeanDefinitionRegistrar接口，在实例化该类会调用其registerBeanDefinitions方法； public class DubboComponentScanRegistrar implements ImportBeanDefinitionRegistrar { @Override public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) { //执行DubboComponentScanRegistrar // 拿到DubboComponentScan注解所定义的包路径，扫描该package下的类，识别这些类上 Set<String> packagesToScan = getPackagesToScan(importingClassMetadata); // 注册ServiceAnnotationBeanPostProcessor一个Bean // 实现了BeanDefinitionRegistryPostProcessor接口，所以在Spring启动时会调用postProcessBeanDefinitionRegistry方法 // 该方法会进行扫描，扫描@Service注解了的类，然后生成BeanDefinition（会生成两个，一个普通的bean，一个ServiceBean），后续的Spring周期中会生成Bean // 在ServiceBean中会监听ContextRefreshedEvent事件，一旦Spring启动完后，就会进行服务导出 registerServiceAnnotationBeanPostProcessor(packagesToScan, registry); // 注册ReferenceAnnotationBeanPostProcessor // 实现了AnnotationInjectedBeanPostProcessor接口，继而实现了InstantiationAwareBeanPostProcessorAdapter接口 // 所以Spring在启动时，在对属性进行注入时会调用AnnotationInjectedBeanPostProcessor接口中的postProcessPropertyValues方法 // 在这个过程中会按照@Refrence注解的信息去生成一个RefrenceBean对象 registerReferenceAnnotationBeanPostProcessor(registry); } //核心方法1，注册一个对@Service注解处理的 BeanDefinitionRegistryPostProcessor private void registerServiceAnnotationBeanPostProcessor(Set<String> packagesToScan, BeanDefinitionRegistry registry) { // 生成一个RootBeanDefinition，对应的beanClass为ServiceAnnotationBeanPostProcessor.class BeanDefinitionBuilder builder = rootBeanDefinition(ServiceAnnotationBeanPostProcessor.class); // 将包路径作为在构造ServiceAnnotationBeanPostProcessor时调用构造方法时的传入参数 builder.addConstructorArgValue(packagesToScan); builder.setRole(BeanDefinition.ROLE_INFRASTRUCTURE); AbstractBeanDefinition beanDefinition = builder.getBeanDefinition(); BeanDefinitionReaderUtils.registerWithGeneratedName(beanDefinition, registry); } //核心方法2，注册一个对属性赋值处理的AnnotationInjectedBeanPostProcessor且带有ApplicationListener事件监听功能 private void registerReferenceAnnotationBeanPostProcessor(BeanDefinitionRegistry registry) { // Register @Reference Annotation Bean Processor // 注册一个ReferenceAnnotationBeanPostProcessor做为bean，ReferenceAnnotationBeanPostProcessor是一个BeanPostProcessor BeanRegistrar.registerInfrastructureBean(registry,ReferenceAnnotationBeanPostProcessor.BEAN_NAME, ReferenceAnnotationBeanPostProcessor.class); } private Set<String> getPackagesToScan(AnnotationMetadata metadata) { AnnotationAttributes attributes = AnnotationAttributes.fromMap( metadata.getAnnotationAttributes(DubboComponentScan.class.getName())); String[] basePackages = attributes.getStringArray("basePackages"); Class<?>[] basePackageClasses = attributes.getClassArray("basePackageClasses"); String[] value = attributes.getStringArray("value"); // Appends value array attributes Set<String> packagesToScan = new LinkedHashSet<String>(Arrays.asList(value)); packagesToScan.addAll(Arrays.asList(basePackages)); for (Class<?> basePackageClass : basePackageClasses) { packagesToScan.add(ClassUtils.getPackageName(basePackageClass)); } if (packagesToScan.isEmpty()) { return Collections.singleton(ClassUtils.getPackageName(metadata.getClassName())); } return packagesToScan; } }
【4】扫描@Service注解，并且进行处理
汇总说明：实际上便是通过处理器扫描@Service注解的类，生成两个Bean【类对应的普通Bean，与Dubbo中要用到的ServiceBean】
其中ServiceBean，是先根据注解上的信息填充对应的属性，后采用环境变量中获取配置的属性，来完成属性填充。
public class ServiceAnnotationBeanPostProcessor implements BeanDefinitionRegistryPostProcessor, EnvironmentAware,ResourceLoaderAware, BeanClassLoaderAware { ... //核心方法1 @Override public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException { Set<String> resolvedPackagesToScan = resolvePackagesToScan(packagesToScan); if (!CollectionUtils.isEmpty(resolvedPackagesToScan)) { // 扫描包，进行Bean注册，核心方法2调用 registerServiceBeans(resolvedPackagesToScan, registry); } else { if (logger.isWarnEnabled()) { logger.warn("packagesToScan is empty , ServiceBean registry will be ignored!"); } } } //核心方法2 private void registerServiceBeans(Set<String> packagesToScan, BeanDefinitionRegistry registry) { DubboClassPathBeanDefinitionScanner scanner = new DubboClassPathBeanDefinitionScanner(registry, environment, resourceLoader); BeanNameGenerator beanNameGenerator = resolveBeanNameGenerator(registry); scanner.setBeanNameGenerator(beanNameGenerator); // 扫描被Service注解标注的类 scanner.addIncludeFilter(new AnnotationTypeFilter(Service.class)); scanner.addIncludeFilter(new AnnotationTypeFilter(com.alibaba.dubbo.config.annotation.Service.class)); for (String packageToScan : packagesToScan) { // Registers @Service Bean first // 扫描Dubbo自定义的@Service注解 scanner.scan(packageToScan); // 查找被@Service注解的类的BeanDefinition（无论这个类有没有被@ComponentScan注解标注了） Set<BeanDefinitionHolder> beanDefinitionHolders = findServiceBeanDefinitionHolders(scanner, packageToScan, registry, beanNameGenerator); if (!CollectionUtils.isEmpty(beanDefinitionHolders)) { // 扫描到BeanDefinition开始处理它，核心方法3的调用 for (BeanDefinitionHolder beanDefinitionHolder : beanDefinitionHolders) { registerServiceBean(beanDefinitionHolder, registry, scanner); } if (logger.isInfoEnabled()) { logger.info(b...); } } else { if (logger.isWarnEnabled()) { logger.warn(...); } } } } //核心方法3 private void registerServiceBean(BeanDefinitionHolder beanDefinitionHolder, BeanDefinitionRegistry registry, DubboClassPathBeanDefinitionScanner scanner) { // 处理扫描到的每一个BeanDefinition // 1. 得到@Service注解上所配置的参数 // 2. 根据每一个BeanDefinition会再额外的生成一个ServiceBean // 3. 对于每一个被@Service注解的类（服务的实现类），会生成两个Bean，一个服务实现类对应的Bean（普通Bean，和@Component一样），一个ServiceBean（Dubbo中要用到的Bean，因为在ServiceBean中包括了很的Config） // 具体的服务实现类 Class<?> beanClass = resolveClass(beanDefinitionHolder); // @Service可以对服务进行各种配置 Annotation service = findServiceAnnotation(beanClass); AnnotationAttributes serviceAnnotationAttributes = getAnnotationAttributes(service, false, false); // 服务实现类对应的接口 Class<?> interfaceClass = resolveServiceInterfaceClass(serviceAnnotationAttributes, beanClass); // 服务实现类对应的bean的名字，比如：demoServiceImpl String annotatedServiceBeanName = beanDefinitionHolder.getBeanName(); // 生成一个ServiceBean，核心方法4的调用 AbstractBeanDefinition serviceBeanDefinition = buildServiceBeanDefinition(service, serviceAnnotationAttributes, interfaceClass, annotatedServiceBeanName); // ServiceBean Bean name ServiceBean表示服务，我们要使用一个服务应该拿ServiceBean String beanName = generateServiceBeanName(serviceAnnotationAttributes, interfaceClass); if (scanner.checkCandidate(beanName, serviceBeanDefinition)) { // check duplicated candidate bean // 把ServiceBean注册进去，对应的beanName为ServiceBean:org.apache.dubbo.demo.DemoService registry.registerBeanDefinition(beanName, serviceBeanDefinition); if (logger.isInfoEnabled()) { logger.info(..); } } else { if (logger.isWarnEnabled()) { logger.warn(...); } } } ... //核心方法4 private AbstractBeanDefinition buildServiceBeanDefinition(Annotation serviceAnnotation,AnnotationAttributes serviceAnnotationAttributes,Class<?> interfaceClass,String annotatedServiceBeanName) { // 生成一个ServiceBean对应的BeanDefinition BeanDefinitionBuilder builder = rootBeanDefinition(ServiceBean.class); AbstractBeanDefinition beanDefinition = builder.getBeanDefinition(); MutablePropertyValues propertyValues = beanDefinition.getPropertyValues(); String[] ignoreAttributeNames = of("provider", "monitor", "application", "module", "registry", "protocol", "interface", "interfaceName", "parameters"); // 把serviceAnnotation中的参数值赋值给ServiceBean的属性 // 如：@Service(test = "test") propertyValues.addPropertyValues(new AnnotationPropertyValuesAdapter(serviceAnnotation, environment, ignoreAttributeNames)); // References "ref" property to annotated-@Service Bean // 如：@Service(protocol = "P1")，这种就是要根据对应的值找到对应的P1的config对象里面的值 // ref属性赋值为另外一个bean, 对应的就是被@Service注解的服务实现类对应的bean addPropertyReference(builder, "ref", annotatedServiceBeanName); // Set interface builder.addPropertyValue("interface", interfaceClass.getName()); // Convert parameters into map builder.addPropertyValue("parameters", convertParameters(serviceAnnotationAttributes.getStringArray("parameters"))); // 配置了methods属性，则给ServiceBean对应的methods属性赋值 // Add methods parameters List<MethodConfig> methodConfigs = convertMethodConfigs(serviceAnnotationAttributes.get("methods")); if (!methodConfigs.isEmpty()) { builder.addPropertyValue("methods", methodConfigs); } /** * Add {@link org.apache.dubbo.config.ProviderConfig} Bean reference */ String providerConfigBeanName = serviceAnnotationAttributes.getString("provider"); if (StringUtils.hasText(providerConfigBeanName)) { addPropertyReference(builder, "provider", providerConfigBeanName); } /** * Add {@link org.apache.dubbo.config.MonitorConfig} Bean reference */ String monitorConfigBeanName = serviceAnnotationAttributes.getString("monitor"); if (StringUtils.hasText(monitorConfigBeanName)) { addPropertyReference(builder, "monitor", monitorConfigBeanName); } /** * Add {@link org.apache.dubbo.config.ApplicationConfig} Bean reference */ String applicationConfigBeanName = serviceAnnotationAttributes.getString("application"); if (StringUtils.hasText(applicationConfigBeanName)) { addPropertyReference(builder, "application", applicationConfigBeanName); } /** * Add {@link org.apache.dubbo.config.ModuleConfig} Bean reference */ String moduleConfigBeanName = serviceAnnotationAttributes.getString("module"); if (StringUtils.hasText(moduleConfigBeanName)) { addPropertyReference(builder, "module", moduleConfigBeanName); } /** * Add {@link org.apache.dubbo.config.RegistryConfig} Bean reference * 获取注解上配置的注册中心的beanName */ String[] registryConfigBeanNames = serviceAnnotationAttributes.getStringArray("registry"); List<RuntimeBeanReference> registryRuntimeBeanReferences = toRuntimeBeanReferences(registryConfigBeanNames); if (!registryRuntimeBeanReferences.isEmpty()) { builder.addPropertyValue("registries", registryRuntimeBeanReferences); } /** * Add {@link org.apache.dubbo.config.ProtocolConfig} Bean reference */ String[] protocolConfigBeanNames = serviceAnnotationAttributes.getStringArray("protocol"); List<RuntimeBeanReference> protocolRuntimeBeanReferences = toRuntimeBeanReferences(protocolConfigBeanNames); if (!protocolRuntimeBeanReferences.isEmpty()) { builder.addPropertyValue("protocols", protocolRuntimeBeanReferences); } return builder.getBeanDefinition(); } .... }
【5】扫描@Reference注解，并且进行处理
1）ReferenceAnnotationBeanPostProcessor类会被调用是基于继承关系
//class ReferenceAnnotationBeanPostProcessor extends AnnotationInjectedBeanPostProcessor //abstract class AnnotationInjectedBeanPostProcessor extends InstantiationAwareBeanPostProcessorAdapter //InstantiationAwareBeanPostProcessorAdapter类便是属性注入时候会调用的 //调用AnnotationInjectedBeanPostProcessor抽象类的postProcessPropertyValues方法 @Override public PropertyValues postProcessPropertyValues( PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) throws BeanCreationException { // 寻找需要注入的属性（被@Reference标注的Field） InjectionMetadata metadata = findInjectionMetadata(beanName, bean.getClass(), pvs); try { metadata.inject(bean, beanName, pvs); } catch (BeanCreationException ex) { throw ex; } catch (Throwable ex) { throw new BeanCreationException(beanName, "Injection of @" + getAnnotationType().getSimpleName() + " dependencies is failed", ex); } return pvs; } //最终走回到ReferenceAnnotationBeanPostProcessor类的doGetInjectedBean方法
2）ReferenceAnnotationBeanPostProcessor中的方法
public class ReferenceAnnotationBeanPostProcessor extends AnnotationInjectedBeanPostProcessor implements ApplicationContextAware, ApplicationListener { ... // 该方法得到的对象会赋值给@ReferenceBean注解的属性 @Override protected Object doGetInjectedBean(AnnotationAttributes attributes, Object bean, String beanName, Class<?> injectedType,InjectionMetadata.InjectedElement injectedElement) throws Exception { // 得到引入服务的beanName // attributes里存的是@Reference注解中的所配置的属性与值 // injectedType表示引入的是哪个服务接口 // referencedBeanName的值为 ServiceBean:org.apache.dubbo.demo.DemoService 表示得到该服务Bean的beanName // referencedBeanName表示 我现在要引用的这个服务，它导出时对应的ServiceBean的beanName是什么，可以用来判断现在我引用的这个服务是不是我自己导出的 String referencedBeanName = buildReferencedBeanName(attributes, injectedType); // @Reference(methods=[Lorg.apache.dubbo.config.annotation.Method;@39b43d60) org.apache.dubbo.demo.DemoService // 我要生成一个RefrenceBean，对应的beanName， 根据@Reference注解来标识不同 String referenceBeanName = getReferenceBeanName(attributes, injectedType); // 生成一个ReferenceBean对象，方法1 ReferenceBean referenceBean = buildReferenceBeanIfAbsent(referenceBeanName, attributes, injectedType); // 把referenceBean添加到Spring容器中去，方法2 registerReferenceBean(referencedBeanName, referenceBean, attributes, injectedType); cacheInjectedReferenceBean(referenceBean, injectedElement); // 创建一个代理对象，Service中的属性被注入的就是这个代理对象 // 内部会调用referenceBean.get(); ，核心方法1 return getOrCreateProxy(referencedBeanName, referenceBeanName, referenceBean, injectedType); } //方法1 private ReferenceBean buildReferenceBeanIfAbsent(String referenceBeanName, AnnotationAttributes attributes, Class<?> referencedType) throws Exception { ReferenceBean<?> referenceBean = referenceBeanCache.get(referenceBeanName); if (referenceBean == null) { // 生成了一个ReferenceBean对象，attributes是@Reference注解的参数值 ReferenceBeanBuilder beanBuilder = ReferenceBeanBuilder .create(attributes, applicationContext) .interfaceClass(referencedType); referenceBean = beanBuilder.build(); referenceBeanCache.put(referenceBeanName, referenceBean); } else if (!referencedType.isAssignableFrom(referenceBean.getInterfaceClass())) { throw new IllegalArgumentException(...); } return referenceBean; } //方法2 private void registerReferenceBean(String referencedBeanName, ReferenceBean referenceBean, AnnotationAttributes attributes, Class<?> interfaceClass) { ConfigurableListableBeanFactory beanFactory = getBeanFactory(); // @Reference(parameters=[Ljava.lang.String;@72ef8d15) org.apache.dubbo.demo.DemoService // ReferenceBean的beanName，注意这个beanName，它是直接取的@Reference的全信息 // 所以，就算引用的是同一个服务，如果@Reference注解上的信息不同，那么就会生成不同的ReferenceBean String beanName = getReferenceBeanName(attributes, interfaceClass); // 要引入的服务就是本地提供的一个服务 if (existsServiceBean(referencedBeanName)) { // If @Service bean is local one /** * Get the @Service's BeanDefinition from {@link BeanFactory} * Refer to {@link ServiceAnnotationBeanPostProcessor#buildServiceBeanDefinition} */ AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) beanFactory.getBeanDefinition(referencedBeanName); RuntimeBeanReference runtimeBeanReference = (RuntimeBeanReference) beanDefinition.getPropertyValues().get("ref"); // ServiceBean --- ref // The name of bean annotated @Service String serviceBeanName = runtimeBeanReference.getBeanName(); // register Alias rather than a new bean name, in order to reduce duplicated beans // 如果是本地提供的一个服务，那么就@Reference(parameters=[Ljava.lang.String;@72ef8d15) org.apache.dubbo.demo.DemoService // 的别名是demoService，不需要是ServiceBean的名字 beanFactory.registerAlias(serviceBeanName, beanName); } else { // Remote @Service Bean if (!beanFactory.containsBean(beanName)) { beanFactory.registerSingleton(beanName, referenceBean); } } } //核心方法1 //这里面其实有点绕，因为@Reference其实也相当于做了@Autowired的工作 //能在本地找到，如果不代理的话其实相当于@Autowired注入属性（不会走Dubbo的逻辑），所以包装成代理，让它也走Dubbo的逻辑 private Object getOrCreateProxy(String referencedBeanName, String referenceBeanName, ReferenceBean referenceBean, Class<?> serviceInterfaceType) { //这个其实是判断本地有没有 if (existsServiceBean(referencedBeanName)) { // If the local @Service Bean exists, build a proxy of ReferenceBean //进行代理，让它走Dubbo的逻辑 return newProxyInstance(getClassLoader(), new Class[]{serviceInterfaceType}, wrapInvocationHandler(referenceBeanName, referenceBean)); } else { // ReferenceBean should be initialized and get immediately // 重点，服务引入的地方 return referenceBean.get(); } } ... }
【6】图示：
Dubbo服务导出
【0】服务导出要做的几件事情：
1. 确定服务的参数 2. 确定服务支持的协议 3. 构造服务最终的URL 4. 将服务URL注册到注册中心去 5. 根据服务支持的不同协议，启动不同的Server，用来接收和处理请求 6. 因为Dubbo支持动态配置服务参数，所以服务导出时还需要绑定一个监听器Listener来监听服务的参数是否有修改，如果发现有修改，则需要重新进行导出
【1】核心点记录
ServiceBean的两种暴露服务的方法 1.利用InitializingBean接口，调用export()方法（没有监听器的情况下才行） 2.利用监听ContextRefreshedEvent事件达到服务暴露
动态代理生成 Invoker 包装成 wrapperInvoker
RegistryProtocol进行注册
DubboProtocol对 Invoker 进行导出，返回一个Exporter
ExchangeServer
【2】ServiceBean是怎么进程服务导出的
//1是利用InitializingBean接口，调用export()方法【主要是调用父类的export()方法和发布ServiceBeanExportedEvent事件】 //2是利用监听ContextRefreshedEvent事件达到服务暴露 public class ServiceBean<T> extends ServiceConfig<T> implements InitializingBean, DisposableBean, ApplicationContextAware, ApplicationListener<ContextRefreshedEvent>, BeanNameAware, ApplicationEventPublisherAware { .... @Override public void setApplicationContext(ApplicationContext applicationContext) { this.applicationContext = applicationContext; // 如果某一个Service是通过Spring暴露的， // 那么当需要获取该服务时就要从Spring容器中进行获取， // 也就是从applicationContext中获取，所以需要把applicationContext添加到SpringExtensionFactory中去 SpringExtensionFactory.addApplicationContext(applicationContext); // 一定要有这一步，不然ServiceBean将接收不到ContextRefreshedEvent事件 supportedApplicationListener = addApplicationListener(applicationContext, this); } //当接收到监听ContextRefreshedEvent事件时候 @Override public void onApplicationEvent(ContextRefreshedEvent event) { // 当前服务没有被导出并且没有卸载，才导出服务 if (!isExported() && !isUnexported()) { if (logger.isInfoEnabled()) { logger.info("The service ready on spring started. service: " + getInterface()); } // 服务导出（服务注册） export(); } } @Override @SuppressWarnings({"unchecked", "deprecation"}) public void afterPropertiesSet() throws Exception { // 如果@Service中没有配置provider if (getProvider() == null) { // 就从Spring容器中找ProviderConfig类型的Bean Map<String, ProviderConfig> providerConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProviderConfig.class, false, false); if (providerConfigMap != null && providerConfigMap.size() > 0) { // 从Spring容器中找ProtocolConfig类型的Bean Map<String, ProtocolConfig> protocolConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProtocolConfig.class, false, false); // 如果存在ProtocolConfig存在，并且存在多个ProviderConfig if (CollectionUtils.isEmptyMap(protocolConfigMap) && providerConfigMap.size() > 1) { // backward compatibility // 如果找到多个，取第一个default等于true的ProviderConfig List<ProviderConfig> providerConfigs = new ArrayList<ProviderConfig>(); for (ProviderConfig config : providerConfigMap.values()) { if (config.isDefault() != null && config.isDefault()) { providerConfigs.add(config); } } if (!providerConfigs.isEmpty()) { setProviders(providerConfigs); } } else { ProviderConfig providerConfig = null; for (ProviderConfig config : providerConfigMap.values()) { if (config.isDefault() == null || config.isDefault()) { if (providerConfig != null) { throw new IllegalStateException(...); } providerConfig = config; } } if (providerConfig != null) { setProvider(providerConfig); } } } } if (getApplication() == null && (getProvider() == null || getProvider().getApplication() == null)) { Map<String, ApplicationConfig> applicationConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ApplicationConfig.class, false, false); if (applicationConfigMap != null && applicationConfigMap.size() > 0) { ApplicationConfig applicationConfig = null; for (ApplicationConfig config : applicationConfigMap.values()) { if (applicationConfig != null) { throw new IllegalStateException(...); } applicationConfig = config; } if (applicationConfig != null) { setApplication(applicationConfig); } } } if (getModule() == null && (getProvider() == null || getProvider().getModule() == null)) { Map<String, ModuleConfig> moduleConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ModuleConfig.class, false, false); if (moduleConfigMap != null && moduleConfigMap.size() > 0) { ModuleConfig moduleConfig = null; for (ModuleConfig config : moduleConfigMap.values()) { if (config.isDefault() == null || config.isDefault()) { if (moduleConfig != null) { throw new IllegalStateException(...); } moduleConfig = config; } } if (moduleConfig != null) { setModule(moduleConfig); } } } // registryIds代码能看到，但是没找到在哪里能配置 if (StringUtils.isEmpty(getRegistryIds())) { if (getApplication() != null && StringUtils.isNotEmpty(getApplication().getRegistryIds())) { setRegistryIds(getApplication().getRegistryIds()); } if (getProvider() != null && StringUtils.isNotEmpty(getProvider().getRegistryIds())) { setRegistryIds(getProvider().getRegistryIds()); } } if ((CollectionUtils.isEmpty(getRegistries())) && (getProvider() == null || CollectionUtils.isEmpty(getProvider().getRegistries())) && (getApplication() == null || CollectionUtils.isEmpty(getApplication().getRegistries()))) { Map<String, RegistryConfig> registryConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, RegistryConfig.class, false, false); if (CollectionUtils.isNotEmptyMap(registryConfigMap)) { List<RegistryConfig> registryConfigs = new ArrayList<>(); if (StringUtils.isNotEmpty(registryIds)) { Arrays.stream(COMMA_SPLIT_PATTERN.split(registryIds)).forEach(id -> { if (registryConfigMap.containsKey(id)) { registryConfigs.add(registryConfigMap.get(id)); } }); } if (registryConfigs.isEmpty()) { for (RegistryConfig config : registryConfigMap.values()) { if (StringUtils.isEmpty(registryIds) && (config.isDefault() == null || config.isDefault().booleanValue())) { registryConfigs.add(config); } } } if (!registryConfigs.isEmpty()) { super.setRegistries(registryConfigs); } } } if (getMetadataReportConfig() == null) { Map<String, MetadataReportConfig> metadataReportConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, MetadataReportConfig.class, false, false); if (metadataReportConfigMap != null && metadataReportConfigMap.size() == 1) { super.setMetadataReportConfig(metadataReportConfigMap.values().iterator().next()); } else if (metadataReportConfigMap != null && metadataReportConfigMap.size() > 1) { throw new IllegalStateException("Multiple MetadataReport configs: " + metadataReportConfigMap); } } if (getConfigCenter() == null) { Map<String, ConfigCenterConfig> configenterMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ConfigCenterConfig.class, false, false); if (configenterMap != null && configenterMap.size() == 1) { super.setConfigCenter(configenterMap.values().iterator().next()); } else if (configenterMap != null && configenterMap.size() > 1) { throw new IllegalStateException("Multiple ConfigCenter found:" + configenterMap); } } if (getMonitor() == null && (getProvider() == null || getProvider().getMonitor() == null) && (getApplication() == null || getApplication().getMonitor() == null)) { Map<String, MonitorConfig> monitorConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, MonitorConfig.class, false, false); if (monitorConfigMap != null && monitorConfigMap.size() > 0) { MonitorConfig monitorConfig = null; for (MonitorConfig config : monitorConfigMap.values()) { if (config.isDefault() == null || config.isDefault()) { if (monitorConfig != null) { throw new IllegalStateException("Duplicate monitor configs: " + monitorConfig + " and " + config); } monitorConfig = config; } } if (monitorConfig != null) { setMonitor(monitorConfig); } } } if (getMetrics() == null) { Map<String, MetricsConfig> metricsConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, MetricsConfig.class, false, false); if (metricsConfigMap != null && metricsConfigMap.size() > 0) { MetricsConfig metricsConfig = null; for (MetricsConfig config : metricsConfigMap.values()) { if (metricsConfig != null) { throw new IllegalStateException("Duplicate metrics configs: " + metricsConfig + " and " + config); } metricsConfig = config; } if (metricsConfig != null) { setMetrics(metricsConfig); } } } // protocolIds也没看到在哪里配置 if (StringUtils.isEmpty(getProtocolIds())) { if (getProvider() != null && StringUtils.isNotEmpty(getProvider().getProtocolIds())) { setProtocolIds(getProvider().getProtocolIds()); } } if (CollectionUtils.isEmpty(getProtocols()) && (getProvider() == null || CollectionUtils.isEmpty(getProvider().getProtocols()))) { Map<String, ProtocolConfig> protocolConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProtocolConfig.class, false, false); if (protocolConfigMap != null && protocolConfigMap.size() > 0) { List<ProtocolConfig> protocolConfigs = new ArrayList<ProtocolConfig>(); if (StringUtils.isNotEmpty(getProtocolIds())) { Arrays.stream(COMMA_SPLIT_PATTERN.split(getProtocolIds())) .forEach(id -> { if (protocolConfigMap.containsKey(id)) { protocolConfigs.add(protocolConfigMap.get(id)); } }); } if (protocolConfigs.isEmpty()) { for (ProtocolConfig config : protocolConfigMap.values()) { if (StringUtils.isEmpty(protocolIds)) { protocolConfigs.add(config); } } } if (!protocolConfigs.isEmpty()) { super.setProtocols(protocolConfigs); } } } if (StringUtils.isEmpty(getPath())) { if (StringUtils.isNotEmpty(beanName) && StringUtils.isNotEmpty(getInterface()) && beanName.startsWith(getInterface())) { setPath(beanName); } } //没有监听事件才做暴露服务 if (!supportedApplicationListener) { export(); } } //服务暴露的核心方法 @Override public void export() { super.export(); // Publish ServiceBeanExportedEvent publishExportEvent(); } private void publishExportEvent() { ServiceBeanExportedEvent exportEvent = new ServiceBeanExportedEvent(this); applicationEventPublisher.publishEvent(exportEvent); } @Override public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) { this.applicationEventPublisher = applicationEventPublisher; } }
1）ServiceConfig类#export()方法
public synchronized void export() { //读取配置并补全（最新最全的配置），方法1 checkAndUpdateSubConfigs(); // 检查服务是否需要导出 if (!shouldExport()) { return; } // 检查是否需要延迟发布 if (shouldDelay()) { DELAY_EXPORT_EXECUTOR.schedule(this::doExport, getDelay(), TimeUnit.MILLISECONDS); } else { // 导出服务，方法2 doExport(); } }
2）方法1：ServiceConfig类#checkAndUpdateSubConfigs()方法
/** * 1. ServiceConfig中的某些属性如果是空的，那么就从ProviderConfig、ModuleConfig、ApplicationConfig中获取 * 2. 从配置中心获取配置，包括应用配置和全局配置 * 3. 从配置中心获取Provider配置 * 4. 从配置中心获取Protocol配置 * 5. 如果ApplicationConfig为空，则构造一个ApplicationConfig * 6. 从配置中心获取Registry配置 * 7. 更新ServiceConfig中的属性为优先级最高的配置 * 8. 更新MetadataReportConfig中的属性为优先级最高的配置 * 9. 检查当前服务是不是一个泛化服务 * 10.检查Stub和Local * 11.检查Mock */ public void checkAndUpdateSubConfigs() { // ServiceConfig中的某些属性如果是空的，那么就从ProviderConfig、ModuleConfig、ApplicationConfig中获取（之前生成的配置Bean） completeCompoundConfigs(); // 方法1.1 // 从配置中心获取配置，包括应用配置和全局配置 // 把获取到的配置放入到Environment中的externalConfigurationMap和appExternalConfigurationMap中 // 并刷新所有的Config属性 startConfigCenter(); // 如果没有ProviderConfig对象，则创建一个 checkDefault(); // 如果没有单独的配置protocols，那么就从provider获取配置的协议，添加到的ServiceConfig中去 // 假如程序员在配置文件中配了一个dubbo协议，配置中心的全局配置或应用配置中也配置了一个协议，那么就会被添加到ServiceConfig中 checkProtocol(); checkApplication(); // if protocol is not injvm checkRegistry // 如果protocol不是只有injvm协议，表示服务调用不是只在本机jvm里面调用，那就需要用到注册中心 // 如果protocol是injvm，表示本地调用 if (!isOnlyInJvm()) { checkRegistry(); } // 刷新ServiceConfig，方法1.2 this.refresh(); // 如果配了metadataReportConfig，那么就刷新配置 checkMetadataReport(); if (StringUtils.isEmpty(interfaceName)) { throw new IllegalStateException("<dubbo:service interface=\"\" /> interface not allow null!"); } // 当前服务对应的实现类是一个GenericService，表示没有特定的接口 if (ref instanceof GenericService) { interfaceClass = GenericService.class; if (StringUtils.isEmpty(generic)) { generic = Boolean.TRUE.toString(); } } else { // 加载接口 try { interfaceClass = Class.forName(interfaceName, true, Thread.currentThread() .getContextClassLoader()); } catch (ClassNotFoundException e) { throw new IllegalStateException(e.getMessage(), e); } // 刷新MethodConfig，并判断MethodConfig中对应的方法在接口中是否存在 checkInterfaceAndMethods(interfaceClass, methods); // 实现类是不是该接口类型 checkRef(); generic = Boolean.FALSE.toString(); } // local和stub一样，不建议使用了 if (local != null) { // 如果本地存根为true，则存根类为interfaceName + "Local" if (Boolean.TRUE.toString().equals(local)) { local = interfaceName + "Local"; } // 加载本地存根类 Class<?> localClass; try { localClass = ClassUtils.forNameWithThreadContextClassLoader(local); } catch (ClassNotFoundException e) { throw new IllegalStateException(e.getMessage(), e); } if (!interfaceClass.isAssignableFrom(localClass)) { throw new IllegalStateException("The local implementation class " + localClass.getName() + " not implement interface " + interfaceName); } } // 本地存根 if (stub != null) { // 如果本地存根为true，则存根类为interfaceName + "Stub" if (Boolean.TRUE.toString().equals(stub)) { stub = interfaceName + "Stub"; } Class<?> stubClass; try { stubClass = ClassUtils.forNameWithThreadContextClassLoader(stub); } catch (ClassNotFoundException e) { throw new IllegalStateException(e.getMessage(), e); } if (!interfaceClass.isAssignableFrom(stubClass)) { throw new IllegalStateException("The stub implementation class " + stubClass.getName() + " not implement interface " + interfaceName); } } // 检查local和stub checkStubAndLocal(interfaceClass); // 检查mock checkMock(interfaceClass); }
3）方法1.1，AbstractInterfaceConfig类#startConfigCenter()方法
void startConfigCenter() { if (configCenter == null) { ConfigManager.getInstance().getConfigCenter().ifPresent(cc -> this.configCenter = cc); } // 如果配置了ConfigCenter if (this.configCenter != null) { // 从其他位置获取配置中心的相关属性信息，比如配置中心地址 // TODO there may have duplicate refresh this.configCenter.refresh(); // 属性更新后，从远程配置中心获取数据(应用配置，全局配置) prepareEnvironment(); } // 从配置中心取到配置数据后，刷新所有的XxConfig中的属性 ConfigManager.getInstance().refreshAll(); } private void prepareEnvironment() { if (configCenter.isValid()) { if (!configCenter.checkOrUpdateInited()) { return; } // 动态配置中心，管理台上的配置中心 DynamicConfiguration dynamicConfiguration = getDynamicConfiguration(configCenter.toUrl()); // 如果是zookeeper，获取的就是/dubbo/config/dubbo/dubbo.properties节点中的内容 String configContent = dynamicConfiguration.getProperties(configCenter.getConfigFile(), configCenter.getGroup()); String appGroup = application != null ? application.getName() : null; String appConfigContent = null; if (StringUtils.isNotEmpty(appGroup)) { // 获取的就是/dubbo/config/dubbo-demo-consumer-application/dubbo.properties节点中的内容 // 这里有bug appConfigContent = dynamicConfiguration.getProperties (StringUtils.isNotEmpty(configCenter.getAppConfigFile()) ? configCenter.getAppConfigFile() : configCenter.getConfigFile(), appGroup ); } try { Environment.getInstance().setConfigCenterFirst(configCenter.isHighestPriority()); Environment.getInstance().updateExternalConfigurationMap(parseProperties(configContent)); Environment.getInstance().updateAppExternalConfigurationMap(parseProperties(appConfigContent)); } catch (IOException e) { throw new IllegalStateException(...); } } }
4）方法1.2，AbstractInterfaceConfig类#refresh()方法
// 刷新XxConfig // 一个XxConfig对象的属性可能是有值的，也可能是没有值的，这时需要从其他位置获取属性值,来进行属性的覆盖 // 覆盖的优先级，从大到小为系统变量->配置中心应用配置->配置中心全局配置->注解或xml中定义->dubbo.properties文件 // 以ServiceConfig为例，ServiceConfig中包括很多属性，比如timeout // 但是在定义一个Service时，如果在注解上没有配置timeout，那么就会其他地方获取timeout的配置 // 比如可以从系统变量->配置中心应用配置->配置中心全局配置->注解或xml中定义->dubbo.properties文件 // refresh是刷新，将当前ServiceConfig上的set方法所对应的属性更新为优先级最高的值 public void refresh() { try { CompositeConfiguration compositeConfiguration = Environment.getInstance().getConfiguration(getPrefix(), getId()); // 表示XxConfig对象本身- AbstractConfig Configuration config = new ConfigConfigurationAdapter(this); //设置顺序， if (Environment.getInstance().isConfigCenterFirst()) { // The sequence would be: SystemConfiguration -> AppExternalConfiguration -> ExternalConfiguration -> AbstractConfig -> PropertiesConfiguration compositeConfiguration.addConfiguration(4, config); } else { // The sequence would be: SystemConfiguration -> AbstractConfig -> AppExternalConfiguration -> ExternalConfiguration -> PropertiesConfiguration compositeConfiguration.addConfiguration(2, config); } // loop methods, get override value and set the new value back to method // Method[] methods = getClass().getMethods(); for (Method method : methods) { // 是不是setXX()方法 if (MethodUtils.isSetter(method)) { // 获取xx配置项的value String value = StringUtils.trim(compositeConfiguration.getString(extractPropertyName(getClass(), method))); // isTypeMatch() is called to avoid duplicate and incorrect update, for example, we have two 'setGeneric' methods in ReferenceConfig. if (StringUtils.isNotEmpty(value) && ClassUtils.isTypeMatch(method.getParameterTypes()[0], value)) { method.invoke(this, ClassUtils.convertPrimitive(method.getParameterTypes()[0], value)); } // 是不是setParameters()方法 } else if (isParametersSetter(method)) { // 获取parameter配置项的value String value = StringUtils.trim(compositeConfiguration.getString(extractPropertyName(getClass(), method))); if (StringUtils.isNotEmpty(value)) { Map<String, String> map = invokeGetParameters(getClass(), this); map = map == null ? new HashMap<>() : map; map.putAll(convert(StringUtils.parseParameters(value), "")); invokeSetParameters(getClass(), this, map); } } } } catch (Exception e) { logger.error("Failed to override ", e); } } public CompositeConfiguration getConfiguration(String prefix, String id) { CompositeConfiguration compositeConfiguration = new CompositeConfiguration(); // Config center has the highest priority // JVM环境变量 compositeConfiguration.addConfiguration(this.getSystemConfig(prefix, id)); // 操作系统环境变量 compositeConfiguration.addConfiguration(this.getEnvironmentConfig(prefix, id)); // 配置中心APP配置 compositeConfiguration.addConfiguration(this.getAppExternalConfig(prefix, id)); // 配置中心Global配置 compositeConfiguration.addConfiguration(this.getExternalConfig(prefix, id)); // dubbo.properties中的配置 compositeConfiguration.addConfiguration(this.getPropertiesConfig(prefix, id)); return compositeConfiguration; }
5）方法2，ServiceConfig类#doExport()方法
protected synchronized void doExport() { // 当前服务已经被取消了，就不能再导出了 if (unexported) { throw new IllegalStateException(...); } // 已经导出了，就不再导出了 if (exported) { return; } exported = true; if (StringUtils.isEmpty(path)) { path = interfaceName; } doExportUrls(); } @SuppressWarnings({"unchecked", "rawtypes"}) private void doExportUrls() { // 得到url，注册服务也是一个服务，所以也会有对应的url，通过调用该url完成服务注册 List<URL> registryURLs = loadRegistries(true); // // 遍历每个协议 // 一个协议一个服务 for (ProtocolConfig protocolConfig : protocols) { // path表示服务名 // contextPath表示应用名（可配置） // pathKey = group/contextpath/path:version // 例子：myGroup/user/org.apache.dubbo.demo.DemoService:1.0.1 String pathKey = URL.buildKey(getContextPath(protocolConfig).map(p -> p + "/" + path).orElse(path), group, version); // ProviderModel中存在服务提供者访问路径，实现类，接口，以及接口中的各个方法对应的ProviderMethodModel // ProviderMethodModel表示某一个方法，方法名，所属的服务的， ProviderModel providerModel = new ProviderModel(pathKey, ref, interfaceClass); // ApplicationModel表示应用中有哪些服务提供者和引用了哪些服务 ApplicationModel.initProviderModel(pathKey, providerModel); // 每种协议导出一个单独的服务,注册到各个注册中心 doExportUrlsFor1Protocol(protocolConfig, registryURLs); } }
6）doExportUrlsFor1Protocol方法
private void doExportUrlsFor1Protocol(ProtocolConfig protocolConfig, List<URL> registryURLs) { // protocolConfig表示某个协议，registryURLs表示所有的注册中心 // 如果配置的某个协议，没有配置name，那么默认为dubbo String name = protocolConfig.getName(); if (StringUtils.isEmpty(name)) { name = DUBBO; } // 这个map表示服务url的参数 Map<String, String> map = new HashMap<String, String>(); map.put(SIDE_KEY, PROVIDER_SIDE); appendRuntimeParameters(map); // 监控中心参数 appendParameters(map, metrics); // 应用相关参数 appendParameters(map, application); // 模块相关参数 appendParameters(map, module); // 提供者相关参数 appendParameters(map, provider); // 协议相关参数 appendParameters(map, protocolConfig); // 服务本身相关参数 appendParameters(map, this); // 服务中某些方法参数 if (CollectionUtils.isNotEmpty(methods)) { for (MethodConfig method : methods) { // 某个方法的配置参数，注意有prefix appendParameters(map, method, method.getName()); String retryKey = method.getName() + ".retry"; // 如果某个方法配置存在xx.retry=false，则改成xx.retry=0 if (map.containsKey(retryKey)) { String retryValue = map.remove(retryKey); if (Boolean.FALSE.toString().equals(retryValue)) { map.put(method.getName() + ".retries", "0"); } } List<ArgumentConfig> arguments = method.getArguments(); if (CollectionUtils.isNotEmpty(arguments)) { // 遍历当前方法配置中的参数配置 for (ArgumentConfig argument : arguments) { // 如果配置了type，则遍历当前接口的所有方法，然后找到方法名和当前方法名相等的方法，可能存在多个 // 如果配置了index,则看index对应位置的参数类型是否等于type,如果相等，则向map中存入argument对象中的参数 // 如果没有配置index，那么则遍历方法所有的参数类型，等于type则向map中存入argument对象中的参数 // 如果没有配置type,但配置了index,则把对应位置的argument放入map // convert argument type if (argument.getType() != null && argument.getType().length() > 0) { Method[] methods = interfaceClass.getMethods(); // visit all methods if (methods != null && methods.length > 0) { for (int i = 0; i < methods.length; i++) { String methodName = methods[i].getName(); // target the method, and get its signature if (methodName.equals(method.getName())) { Class<?>[] argtypes = methods[i].getParameterTypes(); // one callback in the method if (argument.getIndex() != -1) { if (argtypes[argument.getIndex()].getName().equals(argument.getType())) { appendParameters(map, argument, method.getName() + "." + argument.getIndex()); } else { throw new IllegalArgumentException(...); } } else { // multiple callbacks in the method for (int j = 0; j < argtypes.length; j++) { Class<?> argclazz = argtypes[j]; if (argclazz.getName().equals(argument.getType())) { appendParameters(map, argument, method.getName() + "." + j); if (argument.getIndex() != -1 && argument.getIndex() != j) { throw new IllegalArgumentException(...); } } } } } } } } else if (argument.getIndex() != -1) { appendParameters(map, argument, method.getName() + "." + argument.getIndex()); } else { throw new IllegalArgumentException(...); } } } } // end of methods for } if (ProtocolUtils.isGeneric(generic)) { map.put(GENERIC_KEY, generic); map.put(METHODS_KEY, ANY_VALUE); } else { String revision = Version.getVersion(interfaceClass, version); if (revision != null && revision.length() > 0) { map.put(REVISION_KEY, revision); } // 通过接口对应的Wrapper，拿到接口中所有的方法名字 String[] methods = Wrapper.getWrapper(interfaceClass).getMethodNames(); if (methods.length == 0) { logger.warn("No method found in service interface " + interfaceClass.getName()); map.put(METHODS_KEY, ANY_VALUE); } else { map.put(METHODS_KEY, StringUtils.join(new HashSet<String>(Arrays.asList(methods)), ",")); } } // Token是为了防止服务被消费者直接调用（伪造http请求） // 主要是存于注册中心，调用时Token匹配成功即算通过（所以要求调用者是通过注册中心获取提供方的信息） if (!ConfigUtils.isEmpty(token)) { if (ConfigUtils.isDefault(token)) { map.put(TOKEN_KEY, UUID.randomUUID().toString()); } else { map.put(TOKEN_KEY, token); } } // export service // 通过该host和port访问该服务 String host = this.findConfigedHosts(protocolConfig, registryURLs, map); Integer port = this.findConfigedPorts(protocolConfig, name, map); // 服务url URL url = new URL(name, host, port, getContextPath(protocolConfig).map(p -> p + "/" + path).orElse(path), map); // url：http://192.168.40.17:80/org.apache.dubbo.demo.DemoService?anyhost=true&application=dubbo-demo-annotation-provider&bean.name=ServiceBean:org.apache.dubbo.demo.DemoService&bind.ip=192.168.40.17&bind.port=80&deprecated=false&dubbo=2.0.2&dynamic=true&generic=false&interface=org.apache.dubbo.demo.DemoService&methods=sayHello&pid=285072&release=&side=provider×tamp=1585206500409 // 可以通过ConfiguratorFactory，在服务导出时候进行统一配置 if (ExtensionLoader.getExtensionLoader(ConfiguratorFactory.class).hasExtension(url.getProtocol())) { url = ExtensionLoader.getExtensionLoader(ConfiguratorFactory.class).getExtension(url.getProtocol()).getConfigurator(url).configure(url); } String scope = url.getParameter(SCOPE_KEY); // scope可能为null，remote, local,none // don't export when none is configured if (!SCOPE_NONE.equalsIgnoreCase(scope)) { // 如果scope为none,则不会进行任何的服务导出，既不会远程，也不会本地 // export to local if the config is not remote (export to remote only when config is remote) if (!SCOPE_REMOTE.equalsIgnoreCase(scope)) { // 如果scope不是remote,则会进行本地导出，会把当前url的protocol改为injvm，然后进行导出 exportLocal(url); } // export to remote if the config is not local (export to local only when config is local) if (!SCOPE_LOCAL.equalsIgnoreCase(scope)) { // 如果scope不是local,则会进行远程导出 if (CollectionUtils.isNotEmpty(registryURLs)) { // 如果有注册中心，则将服务注册到注册中心 for (URL registryURL : registryURLs) { //if protocol is only injvm ,not register // 如果是injvm，则不需要进行注册中心注册 if (LOCAL_PROTOCOL.equalsIgnoreCase(url.getProtocol())) { continue; } // 该服务是否是动态，对应zookeeper上表示是否是临时节点，对应dubbo中的功能就是静态服务 url = url.addParameterIfAbsent(DYNAMIC_KEY, registryURL.getParameter(DYNAMIC_KEY)); // 基于注册中心地址的到监控中心地址，为什么是基于注册中心地址？ URL monitorUrl = loadMonitor(registryURL); // 把监控中心地址添加到服务url中 if (monitorUrl != null) { url = url.addParameterAndEncoded(MONITOR_KEY, monitorUrl.toFullString()); } // 服务的register参数，如果为true，则表示要注册到注册中心 if (logger.isInfoEnabled()) { if (url.getParameter(REGISTER_KEY, true)) { logger.info(...); } else { logger.info(...); } } // For providers, this is used to enable custom proxy to generate invoker // 服务使用的动态代理机制，如果为空则使用javassit String proxy = url.getParameter(PROXY_KEY); if (StringUtils.isNotEmpty(proxy)) { registryURL = registryURL.addParameter(PROXY_KEY, proxy); } // 生成一个当前服务接口的代理对象 // 使用代理生成一个Invoker，Invoker表示服务提供者的代理，可以使用Invoker的invoke方法执行服务 // 对应的url为 registry://127.0.0.1:2181/org.apache.dubbo.registry.RegistryService?application=dubbo-demo-annotation-provider&dubbo=2.0.2&export=http%3A%2F%2F192.168.40.17%3A80%2Forg.apache.dubbo.demo.DemoService%3Fanyhost%3Dtrue%26application%3Ddubbo-demo-annotation-provider%26bean.name%3DServiceBean%3Aorg.apache.dubbo.demo.DemoService%26bind.ip%3D192.168.40.17%26bind.port%3D80%26deprecated%3Dfalse%26dubbo%3D2.0.2%26dynamic%3Dtrue%26generic%3Dfalse%26interface%3Dorg.apache.dubbo.demo.DemoService%26methods%3DsayHello%26pid%3D19472%26release%3D%26side%3Dprovider%26timestamp%3D1585207994860&pid=19472®istry=zookeeper×tamp=1585207994828 // 这个Invoker中包括了服务的实现者、服务接口类、服务的注册地址（针对当前服务的，参数export指定了当前服务） // 此invoker表示一个可执行的服务，调用invoker的invoke()方法即可执行服务,同时此invoker也可用来导出 Invoker<?> invoker = PROXY_FACTORY.getInvoker(ref, (Class) interfaceClass, registryURL.addParameterAndEncoded(EXPORT_KEY, url.toFullString())); // DelegateProviderMetaDataInvoker也表示服务提供者，包括了Invoker和服务的配置 DelegateProviderMetaDataInvoker wrapperInvoker = new DelegateProviderMetaDataInvoker(invoker, this); // 使用特定的协议来对服务进行导出，这里的协议为RegistryProtocol，导出成功后得到一个Exporter // 1. 先使用RegistryProtocol进行服务注册 // 2. 注册完了之后，使用DubboProtocol进行导出 Exporter<?> exporter = protocol.export(wrapperInvoker); exporters.add(exporter); } } else { // 没有配置注册中心时，也会导出服务 Invoker<?> invoker = PROXY_FACTORY.getInvoker(ref, (Class) interfaceClass, url); DelegateProviderMetaDataInvoker wrapperInvoker = new DelegateProviderMetaDataInvoker(invoker, this); Exporter<?> exporter = protocol.export(wrapperInvoker); exporters.add(exporter); } // 根据服务url，讲服务的元信息存入元数据中心 MetadataReportService metadataReportService = null; if ((metadataReportService = getMetadataReportService()) != null) { metadataReportService.publishProvider(url); } } } this.urls.add(url); }
7）protocol.export的调用
@Override public <T> Exporter<T> export(final Invoker<T> originInvoker) throws RpcException { // 导出服务 // registry:// ---> RegistryProtocol // zookeeper:// ---> ZookeeperRegistry // dubbo:// ---> DubboProtocol // provider:// ---> // 将registry://xxx?xx=xx®istry=zookeeper 转为---> zookeeper://xxx?xx=xx URL registryUrl = getRegistryUrl(originInvoker); // zookeeper://127.0.0.1:2181/org.apache.dubbo.registry.RegistryService?application=dubbo-demo-provider-application&dubbo=2.0.2&export=dubbo%3A%2F%2F192.168.40.17%3A20880%2Forg.apache.dubbo.demo.DemoService%3Fanyhost%3Dtrue%26application%3Ddubbo-demo-provider-application%26bean.name%3DServiceBean%3Aorg.apache.dubbo.demo.DemoService%26bind.ip%3D192.168.40.17%26bind.port%3D20880%26deprecated%3Dfalse%26dubbo%3D2.0.2%26dynamic%3Dtrue%26generic%3Dfalse%26interface%3Dorg.apache.dubbo.demo.DemoService%26logger%3Dlog4j%26methods%3DsayHello%26pid%3D27656%26release%3D2.7.0%26side%3Dprovider%26timeout%3D3000%26timestamp%3D1590735956489&logger=log4j&pid=27656&release=2.7.0×tamp=1590735956479 // 得到服务提供者url URL providerUrl = getProviderUrl(originInvoker); // dubbo://192.168.40.17:20880/org.apache.dubbo.demo.DemoService?anyhost=true&application=dubbo-demo-provider-application&bean.name=ServiceBean:org.apache.dubbo.demo.DemoService&bind.ip=192.168.40.17&bind.port=20880&deprecated=false&dubbo=2.0.2&dynamic=true&generic=false&interface=org.apache.dubbo.demo.DemoService&logger=log4j&methods=sayHello&pid=27656&release=2.7.0&side=provider&timeout=3000×tamp=1590735956489 // Subscribe the override data // FIXME When the provider subscribes, it will affect the scene : a certain JVM exposes the service and call // the same service. Because the subscribed is cached key with the name of the service, it causes the // subscription information to cover. // overrideSubscribeUrl是老版本的动态配置监听url，表示了需要监听的服务以及监听的类型（configurators， 这是老版本上的动态配置） // 在服务提供者url的基础上，生成一个overrideSubscribeUrl，协议为provider://，增加参数category=configurators&check=false final URL overrideSubscribeUrl = getSubscribedOverrideUrl(providerUrl); // 一个overrideSubscribeUrl对应一个OverrideListener，用来监听变化事件，监听到overrideSubscribeUrl的变化后， // OverrideListener就会根据变化进行相应处理，具体处理逻辑看OverrideListener的实现 final OverrideListener overrideSubscribeListener = new OverrideListener(overrideSubscribeUrl, originInvoker); overrideListeners.put(overrideSubscribeUrl, overrideSubscribeListener); // 在这个方法里会利用providerConfigurationListener和serviceConfigurationListener去重写providerUrl // providerConfigurationListener表示应用级别的动态配置监听器，providerConfigurationListener是RegistyProtocol的一个属性 // serviceConfigurationListener表示服务级别的动态配置监听器，serviceConfigurationListener是在每暴露一个服务时就会生成一个 // 这两个监听器都是新版本中的监听器 // 新版本监听的zk路径是： // 服务： /dubbo/config/dubbo/org.apache.dubbo.demo.DemoService.configurators节点的内容 // 应用： /dubbo/config/dubbo/dubbo-demo-provider-application.configurators节点的内容 // 注意，要喝配置中心的路径区分开来，配置中心的路径是： // 应用：/dubbo/config/dubbo/org.apache.dubbo.demo.DemoService/dubbo.properties节点的内容 // 全局：/dubbo/config/dubbo/dubbo.properties节点的内容 providerUrl = overrideUrlWithConfig(providerUrl, overrideSubscribeListener); // export invoker // 根据动态配置重写了providerUrl之后，就会调用DubboProtocol或HttpProtocol去进行导出服务了 final ExporterChangeableWrapper<T> exporter = doLocalExport(originInvoker, providerUrl); // url to registry // 得到注册中心-ZookeeperRegistry final Registry registry = getRegistry(originInvoker); // 得到存入到注册中心去的providerUrl,会对服务提供者url中的参数进行简化 final URL registeredProviderUrl = getRegisteredProviderUrl(providerUrl, registryUrl); // 将当前服务提供者Invoker，以及该服务对应的注册中心地址，以及简化后的服务url存入ProviderConsumerRegTable ProviderInvokerWrapper<T> providerInvokerWrapper = ProviderConsumerRegTable.registerProvider(originInvoker, registryUrl, registeredProviderUrl); //to judge if we need to delay publish //是否需要注册到注册中心 boolean register = providerUrl.getParameter(REGISTER_KEY, true); if (register) { // 注册服务，把简化后的服务提供者url注册到registryUrl中去 register(registryUrl, registeredProviderUrl); providerInvokerWrapper.setReg(true); } // 针对老版本的动态配置，需要把overrideSubscribeListener绑定到overrideSubscribeUrl上去进行监听 // 兼容老版本的配置修改，利用overrideSubscribeListener去监听旧版本的动态配置变化 // 监听overrideSubscribeUrl provider://192.168.40.17:20880/org.apache.dubbo.demo.DemoService?anyhost=true&application=dubbo-demo-annotation-provider&bean.name=ServiceBean:org.apache.dubbo.demo.DemoService&bind.ip=192.168.40.17&bind.port=20880&category=configurators&check=false&deprecated=false&dubbo=2.0.2&dynamic=true&generic=false&interface=org.apache.dubbo.demo.DemoService&methods=sayHello&pid=416332&release=&side=provider×tamp=1585318241955 // 那么新版本的providerConfigurationListener和serviceConfigurationListener是在什么时候进行订阅的呢？在这两个类构造的时候 // Deprecated! Subscribe to override rules in 2.6.x or before. // 老版本监听的zk路径是：/dubbo/org.apache.dubbo.demo.DemoService/configurators/override://0.0.0.0/org.apache.dubbo.demo.DemoService?category=configurators&compatible_config=true&dynamic=false&enabled=true&timeout=6000 // 监听的是路径的内容，不是节点的内容 registry.subscribe(overrideSubscribeUrl, overrideSubscribeListener); exporter.setRegisterUrl(registeredProviderUrl); exporter.setSubscribeUrl(overrideSubscribeUrl); //Ensure that a new exporter instance is returned every time export return new DestroyableExporter<>(exporter); } public void register(URL registryUrl, URL registeredProviderUrl) { Registry registry = registryFactory.getRegistry(registryUrl); // 调用FailbackRegistry类的方法再转到ZookeeperRegistry的register方法 registry.register(registeredProviderUrl); } //FailbackRegistry类（进行失败重试） @Override public void register(URL url) { super.register(url); removeFailedRegistered(url); removeFailedUnregistered(url); try { // 这里才会调用ZookeeperRegistry类的方法 doRegister(url); } catch (Exception e) { Throwable t = e; // If the startup detection is opened, the Exception is thrown directly. boolean check = getUrl().getParameter(Constants.CHECK_KEY, true) && url.getParameter(Constants.CHECK_KEY, true) && !CONSUMER_PROTOCOL.equals(url.getProtocol()); boolean skipFailback = t instanceof SkipFailbackWrapperException; if (check || skipFailback) { if (skipFailback) { t = t.getCause(); } throw new IllegalStateException(...); } else { logger.error(...); } addFailedRegistered(url); } } //ZookeeperRegistry的真正注册的地方 @Override public void doRegister(URL url) { try { zkClient.create(toUrlPath(url), url.getParameter(DYNAMIC_KEY, true)); } catch (Throwable e) { throw new RpcException("Failed to register " + url + " to zookeeper " + getUrl() + ", cause: " + e.getMessage(), e); } }
8）doLocalExport方法
@SuppressWarnings("unchecked")
private <T> ExporterChangeableWrapper<T> doLocalExport(final Invoker<T> originInvoker, URL providerUrl) {
String key = getCacheKey(originInvoker);
return (ExporterChangeableWrapper<T>) bounds.computeIfAbsent(key, s -> {
Invoker<?> invokerDelegate = new InvokerDelegate<>(originInvoker, providerUrl);
// protocol属性的值是哪来的，是在SPI中注入进来的，是一个代理类
// 这里实际利用的就是DubboProtocol或HttpProtocol去export NettyServer
// 为什么需要ExporterChangeableWrapper？方便注销已经被导出的服务
return new ExporterChangeableWrapper<>((Exporter<T>) protocol.export(invokerDelegate), originInvoker);
});
}
@Override
public <T> Exporter<T> export(Invoker<T> invoker) throws RpcException {
URL url = invoker.getUrl();
// export service.
String key = serviceKey(url);
// 构造一个Exporter
DubboExporter<T> exporter = new DubboExporter<T>(invoker, key, exporterMap);
exporterMap.put(key, exporter);
//export an stub service for dispatching event
Boolean isStubSupportEvent = url.getParameter(STUB_EVENT_KEY, DEFAULT_STUB_EVENT);
Boolean isCallbackservice = url.getParameter(IS_CALLBACK_SERVICE, false);
if (isStubSupportEvent && !isCallbackservice) {
String stubServiceMethods = url.getParameter(STUB_EVENT_METHODS_KEY);
if (stubServiceMethods == null || stubServiceMethods.length() == 0) {
if (logger.isWarnEnabled()) {
logger.warn(...);
}
} else {
// 服务的stub方法
stubServiceMethodsMap.put(url.getServiceKey(), stubServiceMethods);
}
}
// 开启NettyServer
openServer(url);
optimizeSerialization(url);
return exporter;
}
private void openServer(URL url) {
// find server.
String key = url.getAddress(); // 获得ip地址和port， 192.168.40.17:20880
// NettyClient, NettyServer
//client can export a service which's only for server to invoke
boolean isServer = url.getParameter(IS_SERVER_KEY, true);
if (isServer) {
// 缓存Server对象
ExchangeServer server = serverMap.get(key);
// DCL，Double Check Lock
if (server == null) {
synchronized (this) {
server = serverMap.get(key);
if (server == null) {
// 创建Server，并进行缓存
serverMap.put(key, createServer(url));
}
}
} else {
// server supports reset, use together with override
// 服务重新导出时，就会走这里
server.reset(url);
}
}
}
private ExchangeServer createServer(URL url) {
url = URLBuilder.from(url)
// send readonly event when server closes, it's enabled by default
.addParameterIfAbsent(CHANNEL_READONLYEVENT_SENT_KEY, Boolean.TRUE.toString())
// enable heartbeat by default
.addParameterIfAbsent(HEARTBEAT_KEY, String.valueOf(DEFAULT_HEARTBEAT))
.addParameter(CODEC_KEY, DubboCodec.NAME)
.build();
// 协议的服务器端实现类型，比如：dubbo协议的mina,netty等，http协议的jetty,servlet等，默认为netty
String str = url.getParameter(SERVER_KEY, DEFAULT_REMOTING_SERVER);
if (str != null && str.length() > 0 && !ExtensionLoader.getExtensionLoader(Transporter.class).hasExtension(str)) {
throw new RpcException("Unsupported server type: " + str + ", url: " + url);
}
// 通过url绑定端口，和对应的请求处理器
ExchangeServer server;
try {
// requestHandler是请求处理器，类型为ExchangeHandler
// 表示从url的端口接收到请求后，requestHandler来进行处理
server = Exchangers.bind(url, requestHandler);
} catch (RemotingException e) {
throw new RpcException("Fail to start server(url: " + url + ") " + e.getMessage(), e);
}
// 协议的客户端实现类型，比如：dubbo协议的mina,netty等
str = url.getParameter(CLIENT_KEY);
if (str != null && str.length() > 0) {
Set<String> supportedTypes = ExtensionLoader.getExtensionLoader(Transporter.class).getSupportedExtensions();
if (!supportedTypes.contains(str)) {
throw new RpcException("Unsupported client type: " + str);
}
}
return server;
}
9）当数据发生改变时 OverrideListener 监听者的处理
@Override public synchronized void notify(List<URL> urls) { List<URL> matchedUrls = getMatchedUrls(urls, subscribeUrl.addParameter(CATEGORY_KEY, CONFIGURATORS_CATEGORY)); // No matching results if (matchedUrls.isEmpty()) { return; } // 对发生了变化的url进行过滤，只取url是override协议，或者参数category等于configurators的url this.configurators = Configurator.toConfigurators(classifyUrls(matchedUrls, UrlUtils::isConfigurator)).orElse(configurators); // 根据Override协议修改 doOverrideIfNecessary(); } public synchronized void doOverrideIfNecessary() { final Invoker<?> invoker; if (originInvoker instanceof InvokerDelegate) { invoker = ((InvokerDelegate<?>) originInvoker).getInvoker(); } else { invoker = originInvoker; } //The origin invoker 当前服务的原始服务提供者url URL originUrl = RegistryProtocol.this.getProviderUrl(invoker); String key = getCacheKey(originInvoker); ExporterChangeableWrapper<?> exporter = bounds.get(key); if (exporter == null) { logger.warn(new IllegalStateException("error state, exporter should not be null")); return; } //The current, may have been merged many times，当前服务被导出的url URL currentUrl = exporter.getInvoker().getUrl(); //根据configurators修改url，configurators是全量的，并不是某个新增的或删除的，所以是基于原始的url进行修改，并不是基于currentUrl //Merged with this configuration URL newUrl = getConfigedInvokerUrl(configurators, originUrl); newUrl = getConfigedInvokerUrl(providerConfigurationListener.getConfigurators(), newUrl); newUrl = getConfigedInvokerUrl(serviceConfigurationListeners.get(originUrl.getServiceKey()).getConfigurators(), newUrl); // 修改过的url如果和目前的url不相同，则重新按newUrl导出 if (!currentUrl.equals(newUrl)) { RegistryProtocol.this.reExport(originInvoker, newUrl); logger.info(...); } } public <T> void reExport(final Invoker<T> originInvoker, URL newInvokerUrl) { // 根据newInvokerUrl进行导出 // update local exporter ExporterChangeableWrapper exporter = doChangeLocalExport(originInvoker, newInvokerUrl); // 获取准确的ProviderUrl // update registry URL registryUrl = getRegistryUrl(originInvoker); // 对于一个服务提供者url，在注册到注册中心时，会先进行简化，所以如果 final URL registeredProviderUrl = getRegisteredProviderUrl(newInvokerUrl, registryUrl); //decide if we need to re-publish // 根据getServiceKey获取ProviderInvokerWrapper ProviderInvokerWrapper<T> providerInvokerWrapper = ProviderConsumerRegTable.getProviderWrapper(registeredProviderUrl, originInvoker); // 生成一个新的ProviderInvokerWrapper ProviderInvokerWrapper<T> newProviderInvokerWrapper = ProviderConsumerRegTable.registerProvider(originInvoker, registryUrl, registeredProviderUrl); /** * Only if the new url going to Registry is different with the previous one should we do unregister and register. * 如果新的服务提供者url简化后的url和这个服务之前的服务提供者url简化后的url不相等，则需要把新的简化后的服务提供者url注册到注册中心去 */ if (providerInvokerWrapper.isReg() && !registeredProviderUrl.equals(providerInvokerWrapper.getProviderUrl())) { unregister(registryUrl, providerInvokerWrapper.getProviderUrl()); register(registryUrl, registeredProviderUrl); newProviderInvokerWrapper.setReg(true); } exporter.setRegisterUrl(registeredProviderUrl); } @SuppressWarnings("unchecked") private <T> ExporterChangeableWrapper doChangeLocalExport(final Invoker<T> originInvoker, URL newInvokerUrl) { String key = getCacheKey(originInvoker); final ExporterChangeableWrapper<T> exporter = (ExporterChangeableWrapper<T>) bounds.get(key); if (exporter == null) { logger.warn(new IllegalStateException("error state, exporter should not be null")); } else { // 到这里才能真正明白，为什么需要InvokerDelegate // InvokerDelegate表示一个调用者，由invoker+url构成，invoker不变，url可变 final Invoker<T> invokerDelegate = new InvokerDelegate<T>(originInvoker, newInvokerUrl); //这次openServer会走HeaderExchangeServer的reset方法 exporter.setExporter(protocol.export(invokerDelegate)); } return exporter; } //这里面存在重新导出，关闭旧的延迟任务（旧的心跳任务），开启新的心跳任务，但是Netty不会关闭，也不会重启 @Override public void reset(URL url) { server.reset(url); try { int currHeartbeat = getHeartbeat(getUrl()); int currIdleTimeout = getIdleTimeout(getUrl()); int heartbeat = getHeartbeat(url); int idleTimeout = getIdleTimeout(url); if (currHeartbeat != heartbeat || currIdleTimeout != idleTimeout) { cancelCloseTask(); startIdleCheckTask(url); } } catch (Throwable t) { logger.error(t.getMessage(), t); } }
【3】汇总
服务导出的入口为ServiceBean中的export()方法，当Spring启动完之后，通过接收Spring的ContextRefreshedEvent事件来触发export()方法的执行。 一个ServiceBean对象就表示一个Dubbo服务，ServiceBean对象中的参数就表示服务的参数，比如timeout，该对象的参数值来至@Service注解中所定义的。 服务导出主要得做两件事情： 1. 根据服务的参数信息，启动对应的网络服务器（netty、tomcat、jetty等），用来接收网络请求 2. 将服务的信息注册到注册中心 但是在做这两件事情之前得先把服务的参数确定好，因为一个Dubbo服务的参数，除开可以在@Service注解中去配置，还会继承Dubbo服务所属应用（Application）上的配置，
还可以在配置中心或JVM环境变量中去配置某个服务的参数，所以首先要做的是确定好当前服务最终的（优先级最高）的参数值。 确定好服务参数之后，就根据所配置的协议启动对应的网络服务器。在启动网络服务器时，并且在网络服务器接收请求的过程中，都可以从服务参数中获取信息，比如最大连接数，线程数，socket超时时间等等。 启动完网络服务器之后，就将服务信息注册到注册中心。同时还有向注册中心注册监听器，监听Dubbo的中的动态配置信息变更。
Dubbo服务引入
【0】核心点记录
生成代理对象（代理对象应该包含的功能）{ 1.获取服务提供者列表 2.Mock--------MockClusterInvoker 3.路由筛选 4.负载均衡 5.集群容错------FailoverClusterInvoker 6.构造NettyClient 7.发送数据（Invocation） } 代理对象的Invoker MockClusterInvoker Invoker属性塞入FailoverClusterInvoker FailoverClusterInvoker Invoker属性塞入DubboInvoker
【1】服务要怎么引入（ReferenceConfig类#get()方法）
//服务引入的入口方法 public synchronized T get() { //读取配置并补全（最新最全的配置） checkAndUpdateSubConfigs(); if (destroyed) { throw new IllegalStateException(...); } if (ref == null) { // 入口 init(); } return ref; // Invoke代理 }
【2】检查并拿到最新配置（ReferenceConfig类#checkAndUpdateSubConfigs()方法）
public void checkAndUpdateSubConfigs() { if (StringUtils.isEmpty(interfaceName)) { throw new IllegalStateException(...); } // 填充ReferenceConfig对象中的属性 completeCompoundConfigs(); // 开启配置中心 startConfigCenter(); // get consumer's global configuration checkDefault(); // 刷新ReferenceConfig对象的属性值 this.refresh(); // 设置泛化 if (getGeneric() == null && getConsumer() != null) { setGeneric(getConsumer().getGeneric()); } if (ProtocolUtils.isGeneric(getGeneric())) { interfaceClass = GenericService.class; } else { try { interfaceClass = Class.forName(interfaceName, true, Thread.currentThread().getContextClassLoader()); } catch (ClassNotFoundException e) { throw new IllegalStateException(...); } checkInterfaceAndMethods(interfaceClass, methods); } resolveFile(); checkApplication(); checkMetadataReport(); }
【3】初始化生成代理对象（ReferenceConfig类#init()方法）
private void init() { if (initialized) { return; } //准备参数，进行参数配置 checkStubAndLocal(interfaceClass); checkMock(interfaceClass); Map<String, String> map = new HashMap<String, String>(); map.put(SIDE_KEY, CONSUMER_SIDE); appendRuntimeParameters(map); if (!ProtocolUtils.isGeneric(getGeneric())) { String revision = Version.getVersion(interfaceClass, version); if (revision != null && revision.length() > 0) { map.put(REVISION_KEY, revision); } String[] methods = Wrapper.getWrapper(interfaceClass).getMethodNames(); if (methods.length == 0) { logger.warn("No method found in service interface " + interfaceClass.getName()); map.put(METHODS_KEY, ANY_VALUE); } else { map.put(METHODS_KEY, StringUtils.join(new HashSet<String>(Arrays.asList(methods)), COMMA_SEPARATOR)); } } map.put(INTERFACE_KEY, interfaceName); appendParameters(map, metrics); appendParameters(map, application); appendParameters(map, module); // remove 'default.' prefix for configs from ConsumerConfig // appendParameters(map, consumer, Constants.DEFAULT_KEY); appendParameters(map, consumer); appendParameters(map, this); Map<String, Object> attributes = null; if (CollectionUtils.isNotEmpty(methods)) { attributes = new HashMap<String, Object>(); for (MethodConfig methodConfig : methods) { appendParameters(map, methodConfig, methodConfig.getName()); String retryKey = methodConfig.getName() + ".retry"; if (map.containsKey(retryKey)) { String retryValue = map.remove(retryKey); if ("false".equals(retryValue)) { map.put(methodConfig.getName() + ".retries", "0"); } } attributes.put(methodConfig.getName(), convertMethodConfig2AsyncInfo(methodConfig)); } } String hostToRegistry = ConfigUtils.getSystemProperty(DUBBO_IP_TO_REGISTRY); if (StringUtils.isEmpty(hostToRegistry)) { hostToRegistry = NetUtils.getLocalHost(); } else if (isInvalidLocalHost(hostToRegistry)) { throw new IllegalArgumentException(...); } map.put(REGISTER_IP_KEY, hostToRegistry); //参数配置完成后去生成代理对象 ref = createProxy(map); String serviceKey = URL.buildKey(interfaceName, group, version); ApplicationModel.initConsumerModel(serviceKey, buildConsumerModel(serviceKey, attributes)); initialized = true; }
【4】生成代理对象（ReferenceConfig类#createProxy()方法）
@SuppressWarnings({"unchecked", "rawtypes", "deprecation"})
private T createProxy(Map<String, String> map) {
if (shouldJvmRefer(map)) {
// injvm://
URL url = new URL(LOCAL_PROTOCOL, LOCALHOST_VALUE, 0, interfaceClass.getName()).addParameters(map);
invoker = REF_PROTOCOL.refer(interfaceClass, url);
} else {
// 为什么会有urls，因为可以在@Reference的url属性中配置多个url，可以是点对点的服务地址，也可以是注册中心的地址
urls.clear(); // reference retry init will add url to urls, lead to OOM
// @Reference中指定了url属性
if (url != null && url.length() > 0) { // user specified URL, could be peer-to-peer address, or register center's address.
String[] us = SEMICOLON_SPLIT_PATTERN.split(url); // 用;号切分
if (us != null && us.length > 0) {
for (String u : us) {
URL url = URL.valueOf(u);
if (StringUtils.isEmpty(url.getPath())) {
url = url.setPath(interfaceName);
}
// 如果是注册中心地址，则在url中添加一个refer参数
if (REGISTRY_PROTOCOL.equals(url.getProtocol())) {
// map表示消费者端配置的参数
urls.add(url.addParameterAndEncoded(REFER_KEY, StringUtils.toQueryString(map)));
} else {
// 如果是服务地址
// 有可能url中配置了参数，map中表示的服务消费者消费服务时的参数，所以需要合并
urls.add(ClusterUtils.mergeUrl(url, map));
}
}
}
} else { // assemble URL from register center's configuration
// @Reference中的protocol属性表示使用哪个协议调用服务，如果不是本地调用协议injvm://，则把注册中心地址找出来
// 对于injvm://协议已经在之前的逻辑中就已经生成invoke了
// if protocols not injvm checkRegistry
if (!LOCAL_PROTOCOL.equalsIgnoreCase(getProtocol())){
checkRegistry();
// 加载注册中心地址
List<URL> us = loadRegistries(false);
if (CollectionUtils.isNotEmpty(us)) {
for (URL u : us) {
URL monitorUrl = loadMonitor(u);
if (monitorUrl != null) {
map.put(MONITOR_KEY, URL.encode(monitorUrl.toFullString()));
}
// 对于注册中心地址都添加REFER_KEY
urls.add(u.addParameterAndEncoded(REFER_KEY, StringUtils.toQueryString(map)));
}
}
if (urls.isEmpty()) {
throw new IllegalStateException(...);
}
}
}
// 如果只有一个url则直接refer得到一个invoker
if (urls.size() == 1) {
// RegistryProtocol.refer() 或者 DubboProtocol.refer()
invoker = REF_PROTOCOL.refer(interfaceClass, urls.get(0));
} else {
// 如果有多个url
// 1. 根据每个url，refer得到对应的invoker
// 2. 如果这多个urls中存在注册中心url，则把所有invoker整合为RegistryAwareClusterInvoker，该Invoker在调用时，会查看所有Invoker中是否有默认的，如果有则使用默认的Invoker，如果没有，则使用第一个Invoker
// 2. 如果这多个urls中不存在注册中心url，则把所有invoker整合为FailoverCluster
List<Invoker<?>> invokers = new ArrayList<Invoker<?>>();
URL registryURL = null; // 用来记录urls中最后一个注册中心url
for (URL url : urls) {
invokers.add(REF_PROTOCOL.refer(interfaceClass, url));
if (REGISTRY_PROTOCOL.equals(url.getProtocol())) {
registryURL = url; // use last registry url
}
}
// 如果存在注册中心地址
if (registryURL != null) { // registry url is available
// use RegistryAwareCluster only when register's CLUSTER is available
URL u = registryURL.addParameter(CLUSTER_KEY, RegistryAwareCluster.NAME);
// StaticDirectory表示静态服务目录，里面的invokers是不会变的, 生成一个RegistryAwareCluster
// The invoker wrap relation would be: RegistryAwareClusterInvoker(StaticDirectory) -> FailoverClusterInvoker(RegistryDirectory, will execute route) -> Invoker
invoker = CLUSTER.join(new StaticDirectory(u, invokers));
} else { // not a registry url, must be direct invoke.
// 如果不存在注册中心地址, 生成一个FailoverClusterInvoker
invoker = CLUSTER.join(new StaticDirectory(invokers));
}
}
}
if (shouldCheck() && !invoker.isAvailable()) {
throw new IllegalStateException(...);
}
MetadataReportService metadataReportService = null;
if ((metadataReportService = getMetadataReportService()) != null) {
URL consumerURL = new URL(CONSUMER_PROTOCOL, map.remove(REGISTER_IP_KEY), 0, map.get(INTERFACE_KEY), map);
metadataReportService.publishConsumer(consumerURL);
}
// create service proxy
return (T) PROXY_FACTORY.getProxy(invoker);
}
【5】PROXY_FACTORY.getProxy等过程
//默认采用JavassistProxyFactory来产生代理对象 public class JavassistProxyFactory extends AbstractProxyFactory { @Override @SuppressWarnings("unchecked") public <T> T getProxy(Invoker<T> invoker, Class<?>[] interfaces) { return (T) Proxy.getProxy(interfaces).newInstance(new InvokerInvocationHandler(invoker)); } @Override public <T> Invoker<T> getInvoker(T proxy, Class<T> type, URL url) { // TODO Wrapper cannot handle this scenario correctly: the classname contains '$' // 如果现在被代理的对象proxy本身就是一个已经被代理过的对象，那么则取代理类的Wrapper，否则取type（接口）的Wrapper // Wrapper是针对某个类或某个接口的包装类，通过wrapper对象可以更方便的去执行某个类或某个接口的方法 final Wrapper wrapper = Wrapper.getWrapper(proxy.getClass().getName().indexOf('$') < 0 ? proxy.getClass() : type); // proxy是服务实现类 // type是服务接口 // url是一个注册中心url，但同时也记录了 return new AbstractProxyInvoker<T>(proxy, type, url) { @Override protected Object doInvoke(T proxy, String methodName, Class<?>[] parameterTypes, Object[] arguments) throws Throwable { // 执行proxy的method方法 // 执行的proxy实例的方法 // 如果没有wrapper，则要通过原生的反射技术去获取Method对象，然后执行 return wrapper.invokeMethod(proxy, methodName, parameterTypes, arguments); } }; } } public class InvokerInvocationHandler implements InvocationHandler { private static final Logger logger = LoggerFactory.getLogger(InvokerInvocationHandler.class); private final Invoker<?> invoker; public InvokerInvocationHandler(Invoker<?> handler) { this.invoker = handler; } @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { String methodName = method.getName(); Class<?>[] parameterTypes = method.getParameterTypes(); if (method.getDeclaringClass() == Object.class) { return method.invoke(invoker, args); } if ("toString".equals(methodName) && parameterTypes.length == 0) { return invoker.toString(); } if ("hashCode".equals(methodName) && parameterTypes.length == 0) { return invoker.hashCode(); } if ("equals".equals(methodName) && parameterTypes.length == 1) { return invoker.equals(args[0]); } // 这里的recreate方法很重要，他会调用AppResponse的recreate方法， // 如果AppResponse对象中存在exception信息，则此方法中会throw这个异常 return invoker.invoke(new RpcInvocation(method, args)).recreate(); } }
【6】对URL的处理过程
1）从@Reference的url属性中配置多个url，然后采用字符串分割的形式拿出来，包装后塞入urls列表中
2）加载注册中心地址
protected List<URL> loadRegistries(boolean provider) { // check && override if necessary List<URL> registryList = new ArrayList<URL>(); if (CollectionUtils.isNotEmpty(registries)) { for (RegistryConfig config : registries) { String address = config.getAddress(); // 如果注册中心没有配地址，则地址为0.0.0.0 if (StringUtils.isEmpty(address)) { address = ANYHOST_VALUE; } // 如果注册中心的地址不是"N/A" if (!RegistryConfig.NO_AVAILABLE.equalsIgnoreCase(address)) { Map<String, String> map = new HashMap<String, String>(); // 把application中的参数放入map中，注意，map中的key是没有prefix的 appendParameters(map, application); // 把config中的参数放入map中，注意，map中的key是没有prefix的 // config是RegistryConfig，表示注册中心 appendParameters(map, config); // 此处path值固定为RegistryService.class.getName()，因为现在是在加载注册中心 map.put(PATH_KEY, RegistryService.class.getName()); // 把dubbo的版本信息和pid放入map中 appendRuntimeParameters(map); // 如果map中如果没有protocol，那么默认为dubbo if (!map.containsKey(PROTOCOL_KEY)) { map.put(PROTOCOL_KEY, DUBBO_PROTOCOL); } // 构造注册中心url，地址+参数 List<URL> urls = UrlUtils.parseURLs(address, map); for (URL url : urls) { url = URLBuilder.from(url) .addParameter(REGISTRY_KEY, url.getProtocol()) .setProtocol(REGISTRY_PROTOCOL) .build(); // 到此为止，url的内容大概为： // registry://127.0.0.1:2181/org.apache.dubbo.registry.RegistryService?application=dubbo-demo-annotation-provider&dubbo=2.0.2&pid=269936®istry=zookeeper×tamp=1584886077813 // 该url表示：使用registry协议调用org.apache.dubbo.registry.RegistryService服务 // 参数为application=dubbo-demo-annotation-provider&dubbo=2.0.2&pid=269936®istry=zookeeper×tamp=1584886077813 // 这里是服务提供者和服务消费者区别的逻辑 // 如果是服务提供者，获取register的值，如果为false，表示该服务不注册到注册中心 // 如果是服务消费者，获取subscribe的值，如果为false，表示该引入的服务不订阅注册中心中的数据 if ((provider && url.getParameter(REGISTER_KEY, true)) || (!provider && url.getParameter(SUBSCRIBE_KEY, true))) { registryList.add(url); } } } } } return registryList; }
【7】invoker的包装过程
1）前置说明
//RegistryProtocol实际上会被两个包装类包装ProtocolListenerWrapper与ProtocolFilterWrapper //如ProtocolListenerWrapper的protocol属性存放ProtocolFilterWrapper //ProtocolFilterWrapper的protocol属性存放RegistryProtocol //然后是Cluster，通过接口可知默认是FailoverCluster，但实际上还会有一个包装类MockClusterWrapper //MockClusterWrapper的cluster属性存放FailoverCluster或者RegistryAwareCluster
2）先是调用REF_PROTOCOL.refer
//ProtocolListenerWrapper的处理 @Override public <T> Invoker<T> refer(Class<T> type, URL url) throws RpcException { if (REGISTRY_PROTOCOL.equals(url.getProtocol())) { return protocol.refer(type, url); } return new ListenerInvokerWrapper<T>(protocol.refer(type, url), Collections.unmodifiableList( ExtensionLoader.getExtensionLoader(InvokerListener.class) .getActivateExtension(url, INVOKER_LISTENER_KEY))); } //ProtocolFilterWrapper的处理 @Override public <T> Invoker<T> refer(Class<T> type, URL url) throws RpcException { if (REGISTRY_PROTOCOL.equals(url.getProtocol())) { return protocol.refer(type, url); } return buildInvokerChain(protocol.refer(type, url), REFERENCE_FILTER_KEY, CommonConstants.CONSUMER); } private static <T> Invoker<T> buildInvokerChain(final Invoker<T> invoker, String key, String group) { Invoker<T> last = invoker; // 根据url获取filter，根据url中的parameters取key为key的value所对应的filter，但是还会匹配group List<Filter> filters = ExtensionLoader.getExtensionLoader(Filter.class).getActivateExtension(invoker.getUrl(), key, group); // ConsumerContextFilter--->FutureFilter--->MonitorFilter // ConsumerContextFilter用来设置RpcContext if (!filters.isEmpty()) { for (int i = filters.size() - 1; i >= 0; i--) { final Filter filter = filters.get(i); final Invoker<T> next = last; last = new Invoker<T>() { @Override public Class<T> getInterface() { return invoker.getInterface(); } @Override public URL getUrl() { return invoker.getUrl(); } @Override public boolean isAvailable() { return invoker.isAvailable(); } @Override public Result invoke(Invocation invocation) throws RpcException { Result asyncResult; try { // 得到一个异步结果 asyncResult = filter.invoke(next, invocation); } catch (Exception e) { // onError callback if (filter instanceof ListenableFilter) { Filter.Listener listener = ((ListenableFilter) filter).listener(); if (listener != null) { listener.onError(e, invoker, invocation); } } throw e; } return asyncResult; } @Override public void destroy() { invoker.destroy(); } @Override public String toString() { return invoker.toString(); } }; } } return new CallbackRegistrationInvoker<>(last, filters); } //RegistryProtocol的处理 public <T> Invoker<T> refer(Class<T> type, URL url) throws RpcException { // 从registry://的url中获取对应的注册中心，比如zookeeper， 默认为dubbo，dubbo提供了自带的注册中心实现 // url由 registry:// 改变为---> zookeeper:// url = URLBuilder.from(url) .setProtocol(url.getParameter(REGISTRY_KEY, DEFAULT_REGISTRY)) .removeParameter(REGISTRY_KEY) .build(); // 拿到注册中心实现，ZookeeperRegistry Registry registry = registryFactory.getRegistry(url); // 下面这个代码，通过过git历史提交记录是用来解决SimpleRegistry不可用的问题 if (RegistryService.class.equals(type)) { return proxyFactory.getInvoker((T) registry, type, url); } // qs表示 queryString, 表示url中的参数，表示消费者引入服务时所配置的参数 Map<String, String> qs = StringUtils.parseQueryString(url.getParameterAndDecoded(REFER_KEY)); // group="a,b" or group="*" String group = qs.get(GROUP_KEY); if (group != null && group.length() > 0) { if ((COMMA_SPLIT_PATTERN.split(group)).length > 1 || "*".equals(group)) { // group有多个值，这里的cluster为MergeableCluster return doRefer(getMergeableCluster(), registry, type, url); } } // 这里的cluster是cluster的Adaptive对象 return doRefer(cluster, registry, type, url); } private <T> Invoker<T> doRefer(Cluster cluster, Registry registry, Class<T> type, URL url) { // RegistryDirectory表示动态服务目录，会和注册中心的数据保持同步 // type表示一个服务对应一个RegistryDirectory，url表示注册中心地址 // 在消费端，最核心的就是RegistryDirectory RegistryDirectory<T> directory = new RegistryDirectory<T>(type, url); directory.setRegistry(registry); directory.setProtocol(protocol); // all attributes of REFER_KEY // 引入服务所配置的参数 Map<String, String> parameters = new HashMap<String, String>(directory.getUrl().getParameters()); // 消费者url URL subscribeUrl = new URL(CONSUMER_PROTOCOL, parameters.remove(REGISTER_IP_KEY), 0, type.getName(), parameters); if (!ANY_VALUE.equals(url.getServiceInterface()) && url.getParameter(REGISTER_KEY, true)) { directory.setRegisteredConsumerUrl(getRegisteredConsumerUrl(subscribeUrl, url)); // 注册简化后的消费url registry.register(directory.getRegisteredConsumerUrl()); } // 构造路由链,路由链会在引入服务时按路由条件进行过滤 // 路由链是动态服务目录中的一个属性，通过路由链可以过滤某些服务提供者 directory.buildRouterChain(subscribeUrl); // 服务目录需要订阅的几个路径 // 当前所引入的服务的消费应用目录：/dubbo/config/dubbo/dubbo-demo-consumer-application.configurators // 当前所引入的服务的动态配置目录：/dubbo/config/dubbo/org.apache.dubbo.demo.DemoService:1.1.1:g1.configurators // 当前所引入的服务的提供者目录：/dubbo/org.apache.dubbo.demo.DemoService/providers // 当前所引入的服务的老版本动态配置目录：/dubbo/org.apache.dubbo.demo.DemoService/configurators // 当前所引入的服务的老版本路由器目录：/dubbo/org.apache.dubbo.demo.DemoService/routers directory.subscribe(subscribeUrl.addParameter(CATEGORY_KEY, PROVIDERS_CATEGORY + "," + CONFIGURATORS_CATEGORY + "," + ROUTERS_CATEGORY)); // 利用传进来的cluster，join得到invoker, Invoker invoker = cluster.join(directory); ProviderConsumerRegTable.registerConsumer(invoker, url, subscribeUrl, directory); return invoker; }
3）再是调用CLUSTER.join
//MockClusterWrapper的处理 public class MockClusterWrapper implements Cluster { private Cluster cluster; public MockClusterWrapper(Cluster cluster) { this.cluster = cluster; } @Override public <T> Invoker<T> join(Directory<T> directory) throws RpcException { return new MockClusterInvoker<T>(directory, this.cluster.join(directory)); } } //有注册中心，RegistryAwareCluster的处理 public class RegistryAwareCluster implements Cluster { public final static String NAME = "registryaware"; @Override public <T> Invoker<T> join(Directory<T> directory) throws RpcException { return new RegistryAwareClusterInvoker<T>(directory); } } //没有注册中心，FailoverCluster的处理 public class FailoverCluster implements Cluster { public final static String NAME = "failover"; @Override public <T> Invoker<T> join(Directory<T> directory) throws RpcException { return new FailoverClusterInvoker<T>(directory); } }
【8】RegistryProtocol里面的监听过程
//directory.subscribe(subscribeUrl.addParameter(CATEGORY_KEY, PROVIDERS_CATEGORY + "," + CONFIGURATORS_CATEGORY + "," + ROUTERS_CATEGORY)); //RegistryDirectory类#subscribe方法 public void subscribe(URL url) { setConsumerUrl(url); CONSUMER_CONFIGURATION_LISTENER.addNotifyListener(this); // 监听consumer应用 serviceConfigurationListener = new ReferenceConfigurationListener(this, url); // 监听所引入的服务的动态配置 registry.subscribe(url, this); //老版本的监听 } //FailbackRegistry类#subscribe方法 @Override public void subscribe(URL url, NotifyListener listener) { super.subscribe(url, listener); removeFailedSubscribed(url, listener); try { // 核心方法 doSubscribe(url, listener); } catch (Exception e) { Throwable t = e; List<URL> urls = getCacheUrls(url); if (CollectionUtils.isNotEmpty(urls)) { notify(url, listener, urls); logger.error(...); } else { // If the startup detection is opened, the Exception is thrown directly. boolean check = getUrl().getParameter(Constants.CHECK_KEY, true) && url.getParameter(Constants.CHECK_KEY, true); boolean skipFailback = t instanceof SkipFailbackWrapperException; if (check || skipFailback) { if (skipFailback) { t = t.getCause(); } throw new IllegalStateException("Failed to subscribe " + url + ", cause: " + t.getMessage(), t); } else { logger.error("Failed to subscribe " + url + ", waiting for retry, cause: " + t.getMessage(), t); } } // Record a failed registration request to a failed list, retry regularly // 添加listener，向zk添加监听器时如果报错了，那么会把这个listener添加到failedSubscribed中，并会定时重试（重新注册listener） addFailedSubscribed(url, listener); } } // 父类AbstractRegistry#subscribe方法 // 把listener添加到subscribed中，subscribed是一个map, 存的是URL:Set<NotifyListener> @Override public void subscribe(URL url, NotifyListener listener) { if (url == null) { throw new IllegalArgumentException("subscribe url == null"); } if (listener == null) { throw new IllegalArgumentException("subscribe listener == null"); } if (logger.isInfoEnabled()) { logger.info("Subscribe: " + url); } Set<NotifyListener> listeners = subscribed.computeIfAbsent(url, n -> new ConcurrentHashSet<>()); listeners.add(listener); } // 进行订阅，先看父类的subscribe方法 @Override public void doSubscribe(final URL url, final NotifyListener listener) { try { if (ANY_VALUE.equals(url.getServiceInterface())) { // 订阅所有服务 String root = toRootPath(); ConcurrentMap<NotifyListener, ChildListener> listeners = zkListeners.get(url); if (listeners == null) { zkListeners.putIfAbsent(url, new ConcurrentHashMap<>()); listeners = zkListeners.get(url); } ChildListener zkListener = listeners.get(listener); if (zkListener == null) { listeners.putIfAbsent(listener, (parentPath, currentChilds) -> { for (String child : currentChilds) { child = URL.decode(child); if (!anyServices.contains(child)) { anyServices.add(child); subscribe(url.setPath(child).addParameters(INTERFACE_KEY, child, Constants.CHECK_KEY, String.valueOf(false)), listener); } } }); zkListener = listeners.get(listener); } zkClient.create(root, false); List<String> services = zkClient.addChildListener(root, zkListener); if (CollectionUtils.isNotEmpty(services)) { for (String service : services) { service = URL.decode(service); anyServices.add(service); subscribe(url.setPath(service).addParameters(INTERFACE_KEY, service, Constants.CHECK_KEY, String.valueOf(false)), listener); } } } else { // 单独订阅某一个服务 List<URL> urls = new ArrayList<>(); // 得到真正要监听的zk上的路径, for (String path : toCategoriesPath(url)) { // 根据监听地址去拿listeners，如果没有则生成 ConcurrentMap<NotifyListener, ChildListener> listeners = zkListeners.get(url); if (listeners == null) { zkListeners.putIfAbsent(url, new ConcurrentHashMap<>()); listeners = zkListeners.get(url); } // 一个NotifyListener对应一个ChildListener ChildListener zkListener = listeners.get(listener); if (zkListener == null) { // lambda表达式就是监听逻辑， parentPath表示父path,currentChilds表示当前拥有的child, 会调用notify方法进行实际的处理 listeners.putIfAbsent(listener, (parentPath, currentChilds) -> ZookeeperRegistry.this.notify(url, listener, toUrlsWithEmpty(url, parentPath, currentChilds))); zkListener = listeners.get(listener); } // 创建zk上路径 zkClient.create(path, false); // 添加真正跟zk相关的ChildListener,ChildListener中的逻辑就是监听到zk上数据发生了变化后会触发的逻辑 List<String> children = zkClient.addChildListener(path, zkListener); if (children != null) { urls.addAll(toUrlsWithEmpty(url, path, children)); } } // 这里的urls就是从现在所引入的服务的目录下查到的url，比如下面这个三个目录下的路径 // "/dubbo/org.apache.dubbo.demo.DemoService/providers" // "/dubbo/org.apache.dubbo.demo.DemoService/configurators" // "/dubbo/org.apache.dubbo.demo.DemoService/routers" notify(url, listener, urls); } } catch (Throwable e) { throw new RpcException("Failed to subscribe " + url + " to zookeeper " + getUrl() + ", cause: " + e.getMessage(), e); } }
【9】监听器触发时
//RegistryDirectory类#notify方法 public synchronized void notify(List<URL> urls) { Map<String, List<URL>> categoryUrls = urls.stream() .filter(Objects::nonNull) .filter(this::isValidCategory) .filter(this::isNotCompatibleFor26x) .collect(Collectors.groupingBy(url -> { if (UrlUtils.isConfigurator(url)) { return CONFIGURATORS_CATEGORY; } else if (UrlUtils.isRoute(url)) { return ROUTERS_CATEGORY; } else if (UrlUtils.isProvider(url)) { return PROVIDERS_CATEGORY; } return ""; })); // 获取动态配置URL，生成configurators List<URL> configuratorURLs = categoryUrls.getOrDefault(CONFIGURATORS_CATEGORY, Collections.emptyList()); this.configurators = Configurator.toConfigurators(configuratorURLs).orElse(this.configurators); // 获取老版本路由URL，生成Router，并添加到路由链中 List<URL> routerURLs = categoryUrls.getOrDefault(ROUTERS_CATEGORY, Collections.emptyList()); toRouters(routerURLs).ifPresent(this::addRouters); // 获取服务提供者URL List<URL> providerURLs = categoryUrls.getOrDefault(PROVIDERS_CATEGORY, Collections.emptyList()); refreshOverrideAndInvoker(providerURLs); } private void refreshOverrideAndInvoker(List<URL> urls) { // mock zookeeper://xxx?mock=return null overrideDirectoryUrl(); refreshInvoker(urls); } // 利用动态配置重写服务目录地址 private void overrideDirectoryUrl() { // merge override parameters this.overrideDirectoryUrl = directoryUrl; List<Configurator> localConfigurators = this.configurators; // local reference doOverrideUrl(localConfigurators); List<Configurator> localAppDynamicConfigurators = CONSUMER_CONFIGURATION_LISTENER.getConfigurators(); // local reference doOverrideUrl(localAppDynamicConfigurators); if (serviceConfigurationListener != null) { List<Configurator> localDynamicConfigurators = serviceConfigurationListener.getConfigurators(); // local reference doOverrideUrl(localDynamicConfigurators); } } private void refreshInvoker(List<URL> invokerUrls) { Assert.notNull(invokerUrls, "invokerUrls should not be null"); if (invokerUrls.size() == 1 && invokerUrls.get(0) != null && EMPTY_PROTOCOL.equals(invokerUrls.get(0).getProtocol())) { this.forbidden = true; // Forbid to access this.invokers = Collections.emptyList(); routerChain.setInvokers(this.invokers); destroyAllInvokers(); // Close all invokers } else { this.forbidden = false; // Allow to access Map<String, Invoker<T>> oldUrlInvokerMap = this.urlInvokerMap; // local reference if (invokerUrls == Collections.<URL>emptyList()) { invokerUrls = new ArrayList<>(); } if (invokerUrls.isEmpty() && this.cachedInvokerUrls != null) { invokerUrls.addAll(this.cachedInvokerUrls); } else { this.cachedInvokerUrls = new HashSet<>(); this.cachedInvokerUrls.addAll(invokerUrls);//Cached invoker urls, convenient for comparison } if (invokerUrls.isEmpty()) { return; } // 这里会先按Protocol进行过滤，并且调用DubboProtocol.refer方法得到DubboInvoker Map<String, Invoker<T>> newUrlInvokerMap = toInvokers(invokerUrls);// Translate url list to Invoker map /** * If the calculation is wrong, it is not processed. * * 1. The protocol configured by the client is inconsistent with the protocol of the server. * eg: consumer protocol = dubbo, provider only has other protocol services(rest). * 2. The registration center is not robust and pushes illegal specification data. * */ if (CollectionUtils.isEmptyMap(newUrlInvokerMap)) { logger.error(...); return; } List<Invoker<T>> newInvokers = Collections.unmodifiableList(new ArrayList<>(newUrlInvokerMap.values())); // pre-route and build cache, notice that route cache should build on original Invoker list. // toMergeMethodInvokerMap() will wrap some invokers having different groups, those wrapped invokers not should be routed. // 得到了所引入的服务Invoker之后，把它们设置到路由链中去，在调用时使用，并且会调用TagRouter的notify方法 routerChain.setInvokers(newInvokers); this.invokers = multiGroup ? toMergeInvokerList(newInvokers) : newInvokers; this.urlInvokerMap = newUrlInvokerMap; try { destroyUnusedInvokers(oldUrlInvokerMap, newUrlInvokerMap); // Close the unused Invoker } catch (Exception e) { logger.warn("destroyUnusedInvokers error. ", e); } } } private Map<String, Invoker<T>> toInvokers(List<URL> urls) { Map<String, Invoker<T>> newUrlInvokerMap = new HashMap<>(); if (urls == null || urls.isEmpty()) { return newUrlInvokerMap; } Set<String> keys = new HashSet<>(); String queryProtocols = this.queryMap.get(PROTOCOL_KEY); // 遍历当前服务所有的服务提供者URL for (URL providerUrl : urls) { // If protocol is configured at the reference side, only the matching protocol is selected if (queryProtocols != null && queryProtocols.length() > 0) { boolean accept = false; String[] acceptProtocols = queryProtocols.split(","); // 当前消费者如果手动配置了Protocol，那么则进行匹配 for (String acceptProtocol : acceptProtocols) { if (providerUrl.getProtocol().equals(acceptProtocol)) { accept = true; break; } } if (!accept) { continue; } } if (EMPTY_PROTOCOL.equals(providerUrl.getProtocol())) { continue; } // 当前Protocol是否在应用中存在对应的扩展点 if (!ExtensionLoader.getExtensionLoader(Protocol.class).hasExtension(providerUrl.getProtocol())) { logger.error(...); continue; } URL url = mergeUrl(providerUrl); String key = url.toFullString(); // The parameter urls are sorted if (keys.contains(key)) { // Repeated url continue; } keys.add(key); // Cache key is url that does not merge with consumer side parameters, regardless of how the consumer combines parameters, if the server url changes, then refer again Map<String, Invoker<T>> localUrlInvokerMap = this.urlInvokerMap; // local reference Invoker<T> invoker = localUrlInvokerMap == null ? null : localUrlInvokerMap.get(key); // 如果当前服务提供者URL没有生产过Invoker if (invoker == null) { // Not in the cache, refer again try { boolean enabled = true; if (url.hasParameter(DISABLED_KEY)) { enabled = !url.getParameter(DISABLED_KEY, false); } else { enabled = url.getParameter(ENABLED_KEY, true); } if (enabled) { // 调用Protocol的refer方法得到一个Invoker invoker = new InvokerDelegate<>(protocol.refer(serviceType, url), url, providerUrl); } } catch (Throwable t) { logger.error(...); } if (invoker != null) { // Put new invoker in cache newUrlInvokerMap.put(key, invoker); } } else { newUrlInvokerMap.put(key, invoker); } } keys.clear(); return newUrlInvokerMap; }