@Override
	public void preCheck(String dataSourceName) {
		if (StringUtils.isEmpty(serverAddr)) {
			serverAddr = this.getEnv().getProperty(
					"spring.cloud.sentinel.datasource.nacos.server-addr",
					"127.0.0.1:8848");
		}
	}
Nacos Properties class Using by {@link DataSourcePropertiesConfiguration} and
{@link NacosDataSourceFactoryBean}.

@author <a href="mailto:fangjian0423@gmail.com">Jim</a>
spring-cloud-alibaba-starters/spring-cloud-alibaba-sentinel-datasource/src/main/java/com/alibaba/cloud/sentinel/datasource/config/NacosDataSourceProperties.java