ES Java API_基于scroll实现月度销售数据批量下载

比如说，现在要下载大批量的数据，从es，放到excel中，月度，或者年度，销售记录，很多，比如几千条，几万条，几十万条

其实就要用到我们es scroll api，对大量数据批量的获取和处理

PUT /car_shop/sales/4
{
"brand": "宝马",
"name": "宝马320",
"price": 320000,
"produce_date": "2017-01-01",
"sale_price": 280000,
"sale_date": "2017-01-25"
}

就是要看宝马的销售记录

2条数据，做一个演示，每个批次下载一条宝马的销售记录，分2个批次给它下载完

package com.roncoo.es.senior;

import java.net.InetAddress;

import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.InetSocketTransportAddress;
import org.elasticsearch.common.unit.TimeValue;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

public class ScollDownloadSalesDataApp {

@SuppressWarnings({ "resource", "unchecked" })
public static void main(String[] args) throws Exception {
Settings settings = Settings.builder()
.put("cluster.name", "elasticsearch")
.build();

TransportClient client = new PreBuiltTransportClient(settings)
.addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("localhost"), 9300));

SearchResponse searchResponse = client.prepareSearch("car_shop")
.setTypes("sales")
.setQuery(QueryBuilders.termQuery("brand.keyword", "宝马"))
.setScroll(new TimeValue(60000))
.setSize(1)
.get();

int batchCount = 0;

do {
for(SearchHit searchHit : searchResponse.getHits().getHits()) {
System.out.println("batch: " + ++batchCount);
System.out.println(searchHit.getSourceAsString());

// 每次查询一批数据，比如1000行，然后写入本地的一个excel文件中

// 如果说你一下子查询几十万条数据，不现实，jvm内存可能都会爆掉
}

searchResponse = client.prepareSearchScroll(searchResponse.getScrollId())
.setScroll(new TimeValue(60000))
.execute()
.actionGet();
} while(searchResponse.getHits().getHits().length != 0);

client.close();
}

}