fix coverity defect

apollo-client/src/main/java/com/ctrip/framework/apollo/ds/ApolloDataSourceProvider.java

@@ -46,7 +46,7 @@ public class ApolloDataSourceProvider implements DataSourceProvider, LogEnabled
          String appId = Foundation.app().getAppId();
          String envType = Foundation.server().getEnvType();
 
-         if (file.hasContent()) {
+         if (file != null && file.hasContent()) {
             String content = file.getContent();
 
             m_logger.info(String.format("Found datasources.xml from Apollo(env=%s, app.id=%s)!", envType, appId));

apollo-client/src/main/java/com/ctrip/framework/apollo/internals/PlainTextConfigFile.java

@@ -12,7 +12,7 @@ public abstract class PlainTextConfigFile extends AbstractConfigFile {
 
   @Override
   public String getContent() {
-    if (m_configProperties.get() == null) {
+    if (!this.hasContent()) {
       return null;
     }
     return m_configProperties.get().getProperty(ConfigConsts.CONFIG_FILE_CONTENT_KEY);

apollo-client/src/main/java/com/ctrip/framework/apollo/internals/PropertiesConfigFile.java

@@ -34,7 +34,7 @@ public class PropertiesConfigFile extends AbstractConfigFile {
   }
 
   String doGetContent() {
-    if (m_configProperties.get() == null) {
+    if (!this.hasContent()) {
       return null;
     }