code: public <T> SQLResult<T> fetchQueryByCursor(Class<T> beanType, SQLResult<T> oldPage ) throws ElasticSearchException {
  		if(oldPage.getCursor() == null ){
  			return null;
  		}
  		SQLRestResponse result = this.client.executeRequest("/_xpack/sql",
  														new StringBuilder().append("{\"cursor\": \"").append(oldPage.getCursor()).append("\"}").toString(),
  														new SQLRestResponseHandler());
  
  		SQLResult<T> datas = ResultUtil.buildFetchSQLResult(  result,  beanType,  oldPage);
  		datas.setClientInterface(this);
  		return datas;
  	}
docs: 发送es restful sql请求/_xpack/sql，获取返回值，返回值类型由beanType决定
  @param beanType
  @param oldPage
  @param <T>
  @return
  @throws ElasticSearchException