apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/service/ReleaseService.java/ReleaseService/getNamespaceItems
class ReleaseService:  private Map<String, String> getNamespaceItems(Namespace namespace) {
    List<Item> items = itemService.findItemsWithOrdered(namespace.getId());
    Map<String, String> configurations = new LinkedHashMap<>();
    for (Item item : items) {
      if (StringUtils.isEmpty(item.getKey())) {
        continue;
      }
      configurations.put(item.getKey(), item.getValue());
    }

    return configurations;
  }