诚之和:如何理解NacosRibbonClientConfiguration

今天就跟大家聊聊有关如何理解NacosRibbonClientConfiguration，可能很多人都不太了解，为了让大家更加了解，小编给大家总结了以下内容，希望大家根据这篇文章可以有所收获。

序

本文主要研究一下NacosRibbonClientConfiguration

NacosRibbonClientConfiguration

spring-cloud-alibaba-0.9.0.RELEASE/spring-cloud-alibaba-nacos-discovery/src/main/java/org/springframework/cloud/alibaba/nacos/ribbon/NacosRibbonClientConfiguration.java

@Configuration@ConditionalOnRibbonNacospublic class NacosRibbonClientConfiguration {@Bean
@ConditionalOnMissingBean
public ServerList<?> ribbonServerList(IClientConfig config, NacosDiscoveryProperties nacosDiscoveryProperties) {
NacosServerList serverList = new NacosServerList(nacosDiscoveryProperties);
serverList.initWithNiwsConfig(config);return serverList;
}
}

• NacosRibbonClientConfiguration会创建NacosServerList

NacosServerList

spring-cloud-alibaba-0.9.0.RELEASE/spring-cloud-alibaba-nacos-discovery/src/main/java/org/springframework/cloud/alibaba/nacos/ribbon/NacosServerList.java

public class NacosServerList extends AbstractServerList<NacosServer> {private NacosDiscoveryProperties discoveryProperties;private String serviceId;public NacosServerList(NacosDiscoveryProperties discoveryProperties) {this.discoveryProperties = discoveryProperties;
}@Override
public List<NacosServer> getInitialListOfServers() {return getServers();
}@Override
public List<NacosServer> getUpdatedListOfServers() {return getServers();
}private List<NacosServer> getServers() {try {
List<Instance> instances = discoveryProperties.namingServiceInstance()
.selectInstances(serviceId, true);return instancesToServerList(instances);
}catch (Exception e) {throw new IllegalStateException("Can not get service instances from nacos, serviceId=" + serviceId,
e);
}
}private List<NacosServer> instancesToServerList(List<Instance> instances) {
List<NacosServer> result = new ArrayList<>();if (null == instances) {return result;
}for (Instance instance : instances) {
result.add(new NacosServer(instance));
}return result;
}public String getServiceId() {return serviceId;
}@Override
public void initWithNiwsConfig(IClientConfig iClientConfig) {this.serviceId = iClientConfig.getClientName();
}
}

• NacosServerList继承了com.netflix.loadbalancer.AbstractServerList，其getInitialListOfServers及getUpdatedListOfServers方法都是调用了getServers；getServers方法则是通过NamingService.selectInstances来获取服务实例信息

NacosServer

spring-cloud-alibaba-0.9.0.RELEASE/spring-cloud-alibaba-nacos-discovery/src/main/java/org/springframework/cloud/alibaba/nacos/ribbon/NacosServer.java

public class NacosServer extends Server {private final MetaInfo metaInfo;private final Instance instance;private final Map<String, String> metadata;public NacosServer(final Instance instance) {super(instance.getIp(), instance.getPort());this.instance = instance;this.metaInfo = new MetaInfo() {@Override
public String getAppName() {return instance.getServiceName();
}@Override
public String getServerGroup() {return null;
}@Override
public String getServiceIdForDiscovery() {return null;
}@Override
public String getInstanceId() {return instance.getInstanceId();
}
};this.metadata = instance.getMetadata();
}@Override
public MetaInfo getMetaInfo() {return metaInfo;
}public Instance getInstance() {return instance;
}public Map<String, String> getMetadata() {return metadata;
}
}

• NacosServer继承了com.netflix.loadbalancer.Server；它主要有metaInfo、instance、metadata三个属性

小结

NacosRibbonClientConfiguration会创建NacosServerList；NacosServerList继承了com.netflix.loadbalancer.AbstractServerList，其getInitialListOfServers及getUpdatedListOfServers方法都是调用了getServers；getServers方法则是通过NamingService.selectInstances来获取服务实例信息