@Override
	public void preCheck(String dataSourceName) {
		if (StringUtils.isEmpty(serverAddr)) {
			serverAddr = this.getEnv()
					.getProperty("spring.cloud.sentinel.datasource.zk.server-addr", "");
			if (StringUtils.isEmpty(serverAddr)) {
				throw new IllegalArgumentException(
						"ZookeeperDataSource server-addr is empty");
			}
		}
	}
Zookeeper Properties class Using by {@link DataSourcePropertiesConfiguration} and
{@link ZookeeperDataSourceFactoryBean}.

@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/ZookeeperDataSourceProperties.java