public static String[] getPropertyNames(PropertySource propertySource) {

		String[] propertyNames = propertySource instanceof EnumerablePropertySource ?
				((EnumerablePropertySource<?>) propertySource).getPropertyNames() : null;

		if (propertyNames == null) {
			propertyNames = EMPTY_STRING_ARRAY;
		}

		return propertyNames;
	}
Get the property names as the array from the specified {@link PropertySource} instance.

@param propertySource {@link PropertySource} instance.
@return non-null
spring-cloud-alibaba-starters/spring-cloud-alibaba-commons/src/main/java/com/alibaba/cloud/commons/context/support/PropertySourcesUtils.java