public void createOrUpdate(final String key, final Object value, final CreateMode mode) {
        if (Objects.nonNull(value)) {
            String val = GsonUtils.getInstance().toJson(value);
            createOrUpdate(key, val, mode);
        } else {
            createOrUpdate(key, "", mode);
        }
    }
create or update key with value.

@param key   zookeeper path key.
@param value object value.
@param mode  creation mode.
shenyu-admin/src/main/java/org/apache/shenyu/admin/mode/cluster/impl/zookeeper/ClusterZookeeperClient.java