apollo-portal/src/main/java/com/ctrip/framework/apollo/openapi/server/service/ServerItemOpenApiService.java/ServerItemOpenApiService/removeItem
class ServerItemOpenApiService:  @Override
  public void removeItem(String appId, String env, String clusterName, String namespaceName,
      String key, String operator) {
    ItemDTO toDeleteItem = this.itemService.loadItem(Env.valueOf(env), appId, clusterName, namespaceName, key);
    this.itemService.deleteItem(Env.valueOf(env), toDeleteItem.getId(), operator);
  }