code: public <T> ESDatas<T> searchAll(String index,  int fetchSize ,ScrollHandler<T> scrollHandler,Class<T> type) throws ElasticSearchException{
  		StringBuilder builder = new StringBuilder();
  		String queryAll = builder.append("{ \"size\":").append(fetchSize).append(",\"query\": {\"match_all\": {}},\"sort\": [\"_doc\"]}").toString();
  		builder.setLength(0);
  		return this.scroll(builder.append(index).append("/_search").toString(),queryAll,"10m",type,scrollHandler);
  	}
docs: 检索索引所有数据
  @param index
  @param fetchSize 指定每批次返回的数据，不指定默认为5000
  @param scrollHandler 每批数据处理方法
  @param type
  @param <T>
  @return
  @throws ElasticSearchException