do some refactor

spring-cloud-alibaba-nacos-config/src/main/java/com/alibaba/cloud/nacos/NacosConfigProperties.java

@@ -22,6 +22,7 @@ import java.util.Properties;
 
 import javax.annotation.PostConstruct;
 
+import com.alibaba.cloud.nacos.diagnostics.analyzer.NacosConnectionFailureException;
 import com.alibaba.nacos.api.NacosFactory;
 import com.alibaba.nacos.api.config.ConfigService;
 import com.alibaba.nacos.api.exception.NacosException;
@@ -367,8 +368,8 @@ public class NacosConfigProperties {
 						.createConfigService(getConfigServiceProperties());
 			}
 			catch (NacosException e) {
-				log.error("create naming service error!properties={},e=,", this, e);
-				return null;
+				throw new NacosConnectionFailureException(this.getServerAddr(),
+						e.getMessage(), e);
 			}
 		}
 		return configService;

spring-cloud-alibaba-nacos-config/src/main/java/com/alibaba/cloud/nacos/parser/AbstractNacosDataParser.java

@@ -21,7 +21,7 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Properties;
 
-import com.alibaba.nacos.client.utils.StringUtils;
+import org.springframework.util.StringUtils;
 
 /**
  * @author zkz
@@ -118,7 +118,7 @@ public abstract class AbstractNacosDataParser {
 		Properties properties = new Properties();
 		for (Map.Entry<String, String> entry : map.entrySet()) {
 			String key = entry.getKey();
-			if (StringUtils.isBlank(key)) {
+			if (StringUtils.isEmpty(key)) {
 				continue;
 			}
 			key = key.startsWith(DOT) ? key.replaceFirst("\\.", "") : key;

spring-cloud-alibaba-nacos-config/src/main/java/com/alibaba/cloud/nacos/parser/NacosDataJsonParser.java

@@ -22,10 +22,11 @@ import java.util.Iterator;
 import java.util.Map;
 import java.util.Properties;
 
-import com.alibaba.nacos.client.utils.StringUtils;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 
+import org.springframework.util.StringUtils;
+
 /**
  * @author zkz
  */

spring-cloud-alibaba-nacos-config/src/main/java/com/alibaba/cloud/nacos/parser/NacosDataXmlParser.java

@@ -25,13 +25,14 @@ import java.util.Properties;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 
-import com.alibaba.nacos.client.utils.StringUtils;
 import org.w3c.dom.Document;
 import org.w3c.dom.NamedNodeMap;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 import org.xml.sax.InputSource;
 
+import org.springframework.util.StringUtils;
+
 /**
  * With relatively few usage scenarios, only simple parsing is performed to reduce jar
  * dependencies.

spring-cloud-alibaba-nacos-discovery/src/main/java/com/alibaba/cloud/nacos/NacosDiscoveryProperties.java

@@ -465,7 +465,6 @@ public class NacosDiscoveryProperties {
 		}
 	}
 
-	@Deprecated
 	public NamingService namingServiceInstance() {
 
 		if (null != namingService) {