熟练掌握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，我们说，月度，或者年度，销售记录，很多，比如几千条，几万条，几十万条
其实就要用到我们之前讲解的es scroll api，对大量数据批量的获取和处理

PUT /car_shop/cars/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
做一个演示,每个批次下载一条宝马的销售记录,分几个批次给它下载完

Settings settings = Settings.builder()
        .put("cluster.name", "my-application")
        .put("client.transport.sniff", true)
        .build();

TransportClient client = new PreBuiltTransportClient(settings).
        addTransportAddress(new TransportAddress(InetAddress.getByName("192.168.80.188"), 9300));

SearchResponse searchResponse = client.prepareSearch("car_shop")
        .setTypes("cars")
        .setQuery(QueryBuilders.termQuery("brand", "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());
    }
    searchResponse = client.prepareSearchScroll(searchResponse.getScrollId())
            .setScroll(new TimeValue(60000))
            .execute().actionGet();
} while (searchResponse.getHits().getHits().length != 0);

client.close();