文章目录

• Java-Chassis
• • @EnableServiceComb初始化SCB
  • SPIServiceUtils自定义SPI加载器
  • 职责链管理器FilterChainsManager/ConsumerHandlerManager
  • @RpcSchema
  • 注册服务如何保活？
  • @RpcReference
  • PropertySourcesPlaceholderConfigurer
  • ThreadPoolExecutorEx/LinkedBlockingQueueEx
  • ConcurrentHashMapEx
  • AopProxyUtils/BeanUtils
  • ReflectionUtils
  • StringValueResolver

Java-Chassis

ServiceComb中是实现RPC的框架类似Dubbo，又称Java底座。

@EnableServiceComb初始化SCB

通过@ImportResource的方式导入ServiceComb的核心Bean定义文件"classpath*:META-INF/spring/scb-core-bean.xml";和"classpath*:META-INF/spring/*.bean.xml";，注入如下Bean定义。

• ConfigurationSpringInitializer

• CseApplicationListener，ContextRefreshedEvent事件监听器

  • 初始化相关的连接

    if (this.applicationContext == applicationContext) {// same object. avoid initialize many times.return;}this.applicationContext = applicationContext;BeanUtils.setContext(applicationContext);HttpClients.load(); // Http相关的RegistrationManager.INSTANCE.init(); // 服务注册 管理初始化，通过SPI获取。DiscoveryManager.INSTANCE.init(); // 服务发现 管理初始化，通过SPI获取。
    

  • ContextRefreshedEvent Bean实例化完事件触达，初始化ServiceComb引擎SCBEngine

    @Overridepublic void onApplicationEvent(ApplicationEvent event) {if (initEventClass.isInstance(event)) {if (applicationContext instanceof AbstractApplicationContext) {((AbstractApplicationContext) applicationContext).registerShutdownHook();}SCBEngine scbEngine = SCBEngine.getInstance(); // 获取单例//SCBEngine init first, hence we do not need worry that when other beans need use the//producer microserviceMeta, the SCBEngine is not inited.
    //        String serviceName = RegistryUtils.getMicroservice().getServiceName();
    //        SCBEngine.getInstance().setProducerMicroserviceMeta(new MicroserviceMeta(serviceName).setConsumer(false));
    //        SCBEngine.getInstance().setProducerProviderManager(applicationContext.getBean(ProducerProviderManager.class));
    //        SCBEngine.getInstance().setConsumerProviderManager(applicationContext.getBean(ConsumerProviderManager.class));
    //        SCBEngine.getInstance().setTransportManager(applicationContext.getBean(TransportManager.class));scbEngine.setApplicationContext(applicationContext);scbEngine.setPriorityPropertyManager(applicationContext.getBean(PriorityPropertyManager.class));scbEngine.setFilterChainsManager(applicationContext.getBean(FilterChainsManager.class)); // 指责链管理类scbEngine.getConsumerProviderManager().getConsumerProviderList().addAll(applicationContext.getBeansOfType(ConsumerProvider.class).values()); // 获取支持的Consumer形式，如Rest/PojoscbEngine.getProducerProviderManager().getProducerProviderList().addAll(applicationContext.getBeansOfType(ProducerProvider.class).values()); // // 获取Provider注册的元信息，支持从Rest/Pojo中获取scbEngine.addBootListeners(applicationContext.getBeansOfType(BootListener.class).values()); // 获取全量SCB初始化监听器BootListener，用于监听SCB在生命周期内的各种事件。scbEngine.run();} else if (event instanceof ContextClosedEvent) {if (SCBEngine.getInstance() != null) {SCBEngine.getInstance().destroy();}}}
    

• org.apache.servicecomb.core.executor.GroupExecutor

SPIServiceUtils.getOrLoadSortedService(Registration.class)

SPIServiceUtils自定义SPI加载器

ServiceComb大量使用SPI动态扩展对应的实现，SPI定义的使能及优先级，从全部jar包中

META-INF/services的路径文件中加载扩展类，文件名为接口类的全路径里面内容为接口实现。

• SPIOrder，加载SPI的顺序，排序从小到大，order数值越小，优先级越高，调用越靠前。

• SPIEnabled，当前SPI是否使能。

• SPIServiceUtils，代理到JDK自带的ServiceLoader动态加载SPI类，并使用ReflectionUtils用于获取SPIOrder排序对应的实现类。

  // 加载SPI全部类
  public static  List loadSortedService(Class serviceType) {List> serviceEntries = new ArrayList<>();ServiceLoader serviceLoader = ServiceLoader.load(serviceType); // 代理到JDKserviceLoader.forEach(service -> {int serviceOrder = 0;Method getOrder = ReflectionUtils.findMethod(service.getClass(), "getOrder"); // 默认为0，如果获取方法if (getOrder != null) {serviceOrder = (int) ReflectionUtils.invokeMethod(getOrder, service); // 触发方法}Entry entry = new SimpleEntry<>(serviceOrder, service);serviceEntries.add(entry);});List services = serviceEntries.stream().sorted(Comparator.comparingInt(Entry::getKey)).map(Entry::getValue).collect(Collectors.toList()); // 根据 getOrder 排序，并返回全部的serviceType。LOGGER.info("Found SPI service {}, count={}.", serviceType.getName(), services.size());for (int idx = 0; idx < services.size(); idx++) {T service = services.get(idx);LOGGER.info("  {}. {}.", idx, service.getClass().getName());} // 输出加载的日志及其顺序，方便定位调试功能return services;}
  // Map, List