Eureka 學習筆記（七）EurekaServerContext初始化（1）- 原生Eureka對比Spring-Cloud-Netfix-Eureka

一、原生Eureka

protected void initEurekaServerContext() throws Exception {
    EurekaServerConfig eurekaServerConfig = new DefaultEurekaServerConfig();

    // For backward compatibility
    JsonXStream.getInstance().registerConverter(new V1AwareInstanceInfoConverter(), XStream.PRIORITY_VERY_HIGH);
    XmlXStream.getInstance().registerConverter(new V1AwareInstanceInfoConverter(), XStream.PRIORITY_VERY_HIGH);

    logger.info("Initializing the eureka client...");
    logger.info(eurekaServerConfig.getJsonCodecName());
    ServerCodecs serverCodecs = new DefaultServerCodecs(eurekaServerConfig);

    ApplicationInfoManager applicationInfoManager = null;

    if (eurekaClient == null) {
        EurekaInstanceConfig instanceConfig = isCloud(ConfigurationManager.getDeploymentContext())
                ? new CloudInstanceConfig()
                : new MyDataCenterInstanceConfig();
        
        applicationInfoManager = new ApplicationInfoManager(
                instanceConfig, new EurekaConfigBasedInstanceInfoProvider(instanceConfig).get());
        
        EurekaClientConfig eurekaClientConfig = new DefaultEurekaClientConfig();
        eurekaClient = new DiscoveryClient(applicationInfoManager, eurekaClientConfig);
    } else {
        applicationInfoManager = eurekaClient.getApplicationInfoManager();
    }

    PeerAwareInstanceRegistry registry;
    if (isAws(applicationInfoManager.getInfo())) {
        registry = new AwsInstanceRegistry(
                eurekaServerConfig,
                eurekaClient.getEurekaClientConfig(),
                serverCodecs,
                eurekaClient
        );
        awsBinder = new AwsBinderDelegate(eurekaServerConfig, eurekaClient.getEurekaClientConfig(), registry, applicationInfoManager);
        awsBinder.start();
    } else {
        registry = new PeerAwareInstanceRegistryImpl(
                eurekaServerConfig,
                eurekaClient.getEurekaClientConfig(),
                serverCodecs,
                eurekaClient
        );
    }

    PeerEurekaNodes peerEurekaNodes = getPeerEurekaNodes(
            registry,
            eurekaServerConfig,
            eurekaClient.getEurekaClientConfig(),
            serverCodecs,
            applicationInfoManager
    );

    serverContext = new DefaultEurekaServerContext(
            eurekaServerConfig,
            serverCodecs,
            registry,
            peerEurekaNodes,
            applicationInfoManager
    );

    EurekaServerContextHolder.initialize(serverContext);

    serverContext.initialize();
    logger.info("Initialized server context");

    // Copy registry from neighboring eureka node
    int registryCount = registry.syncUp();
    registry.openForTraffic(applicationInfoManager, registryCount);

    // Register all monitoring statistics.
    EurekaMonitors.registerAllStats();
}

二、Spring-Cloud-Netfix-Eureka

protected void initEurekaServerContext() throws Exception {
	// For backward compatibility
	JsonXStream.getInstance().registerConverter(new V1AwareInstanceInfoConverter(),
			XStream.PRIORITY_VERY_HIGH);
	XmlXStream.getInstance().registerConverter(new V1AwareInstanceInfoConverter(),
			XStream.PRIORITY_VERY_HIGH);

	if (isAws(this.applicationInfoManager.getInfo())) {
		this.awsBinder = new AwsBinderDelegate(this.eurekaServerConfig,
				this.eurekaClientConfig, this.registry, this.applicationInfoManager);
		this.awsBinder.start();
	}

	EurekaServerContextHolder.initialize(this.serverContext);

	log.info("Initialized server context");

	// Copy registry from neighboring eureka node
	int registryCount = this.registry.syncUp();
	this.registry.openForTraffic(this.applicationInfoManager, registryCount);

	// Register all monitoring statistics.
	EurekaMonitors.registerAllStats();
}

三、對比

    通過閱讀源碼可以發現Spring-Cloud-Netfix-Eureka相比於原生Eureka，少了很多組件的裝配，其實在Spring-Cloud中，是用自動裝配的機制給裝配了，具體缺少的類可以在EurekaServerAutoConfiguration和EurekaClientAutoConfiguration兩個配置類中找到， 這裏就不寫了~下一篇大致介紹initEurekaServerContext方法的執行流程。