DubboBootstrap bootstrap = DubboBootstrap.getInstance();
 bootstrap.application(new ApplicationConfig("dubbo-demo-api-provider"))
            .registry(new RegistryConfig("zookeeper://127.0.0.1:2181"))
            .protocol(new ProtocolConfig(CommonConstants.DUBBO, -1))
            .service(service)
            .start()
            .await();

bootstrap.application(new ApplicationConfig("dubbo-demo-api-provider"))

 DubboBootstrap bootstrap = DubboBootstrap.getInstance();
 bootstrap.application(new ApplicationConfig("dubbo-demo-api-provider"))

 public DubboBootstrap application(ApplicationConfig applicationConfig) {
 		//将启动器构造器中初始化的默认应用程序模型对象传递给配置对象
        applicationConfig.setScopeModel(applicationModel);
        //将配置信息添加到配置管理器中
        configManager.setApplication(applicationConfig);
        return this;
    }

  @DisableInject
    public void setApplication(ApplicationConfig application) {
        addConfig(application);
    }

public final <T extends AbstractConfig> T addConfig(AbstractConfig config) {
		
        if (config == null) {
            return null;
        }
        // ignore MethodConfig
        //检查当前配置管理器支持管理的配置对象
        //目前支持的配置有ApplicationConfig,MonitorConfig,MetricsConfig,SslConfig,
        //ProtocolConfig,RegistryConfig,ConfigCenterConfig,MetadataReportConfig
        if (!isSupportConfigType(config.getClass())) {
            throw new IllegalArgumentException("Unsupported config type: " + config);
        }
		
        if (config.getScopeModel() != scopeModel) {
            config.setScopeModel(scopeModel);
        }
		
		//缓存中是否存在
        Map<String, AbstractConfig> configsMap = configsCache.computeIfAbsent(getTagName(config.getClass()), type -> new ConcurrentHashMap<>());

        // fast check duplicated equivalent config before write lock
        //不是服务级配置则直接从缓存中读取到配置之后直接返回
        if (!(config instanceof ReferenceConfigBase || config instanceof ServiceConfigBase)) {
            for (AbstractConfig value : configsMap.values()) {
                if (value.equals(config)) {
                    return (T) value;
                }
            }
        }

        // lock by config type
        //添加配置
        synchronized (configsMap) {
            return (T) addIfAbsent(config, configsMap);
        }
    }

private <C extends AbstractConfig> C addIfAbsent(C config, Map<String, C> configsMap)
        throws IllegalStateException {
		//配置信息为空直接返回
        if (config == null || configsMap == null) {
            return config;
        }

        // find by value
        //根据配置规则判断,配置存在则返回
        Optional<C> prevConfig = findDuplicatedConfig(configsMap, config);
        if (prevConfig.isPresent()) {
            return prevConfig.get();
        }
		
		//生成配置key
        String key = config.getId();
        if (key == null) {
            do {
                // generate key if id is not set
                key = generateConfigId(config);
            } while (configsMap.containsKey(key));
        }

		//不相同的配置key重复则抛出异常
        C existedConfig = configsMap.get(key);
        if (existedConfig != null && !isEquals(existedConfig, config)) {
            String type = config.getClass().getSimpleName();
            logger.warn(String.format("Duplicate %s found, there already has one default %s or more than two %ss have the same id, " +
                    "you can try to give each %s a different id, override previous config with later config. id: %s, prev: %s, later: %s",
                type, type, type, type, key, existedConfig, config));
        }

        // override existed config if any
        //将配置对象存入configsMap对象中,configsMap来源于configsCache
        configsMap.put(key, config);
        return config;
    }