Update PropertySourceExtensionLoader.java

Author: mercyblitz

microsphere-spring-context/src/main/java/io/microsphere/spring/config/context/annotation/PropertySourceExtensionLoader.java

@@ -144,14 +144,17 @@ protected void addPropertySource(EA extensionAttributes, MutablePropertySources
             String relativePropertySourceName = extensionAttributes.getAfterPropertySourceName();
             if (hasText(relativePropertySourceName)) {
                 propertySources.addAfter(relativePropertySourceName, propertySource);
-            } else {
-                relativePropertySourceName = extensionAttributes.getBeforePropertySourceName();
+                return;
             }
+
+            relativePropertySourceName = extensionAttributes.getBeforePropertySourceName();
             if (hasText(relativePropertySourceName)) {
                 propertySources.addBefore(relativePropertySourceName, propertySource);
-            } else {
-                propertySources.addLast(propertySource);
+                return;
             }
+
+            //  default, add the PropertySource into last
+            propertySources.addLast(propertySource);
         }
     }