code: public static void reload(String key) {
          KV<String, SplitWord> kv = CRF.get(key);
          if (kv != null) {
              CRF.get(key).setV(null);
          }
  
          LOG.warn("make sure ,this reload not use same obj , it to instance a new model");
      }
docs: 刷新一个,将值设置为null
  
  @param key
  @return