Elasticsearch Java API 的使用（8）—Scroll (游标)API详解

滚动查询

Elasticsearch中进行大数据量查询时，往往因为设备、网络传输问题影响查询数据的效率；Elasticsearch中提供了Scroll（游标）的方式对数据进行少量多批次的滚动查询，来提高查询效率。

public class Scroll {    public static void main(String[] args) {        try{            long startTime = System.currentTimeMillis();            /*创建客户端*/            //client startup            //设置集群名称            Settings settings = Settings.builder()                    .put("cluster.name", "elsearch")                    .put("client.transport.sniff", true)                    .build();            //创建client            TransportClient client = new PreBuiltTransportClient(settings)                    .addTransportAddress(new InetSocketTransportAddress(                    InetAddress.getByName("54.223.232.95"),9300));            List<String> result = new ArrayList<>();            String scrollId = "";            //第一次请求            SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();            //TODO: 设置查询条件            RangeQueryBuilder rangequerybuilder = QueryBuilders                .rangeQuery("inputtime")                .from("2016-12-14 02:00:00").to("2016-12-14 07:59:59");            sourceBuilder.query(QueryBuilders.boolQuery()                .must(QueryBuilders                        .matchPhraseQuery("pointid","W3.UNIT1.10HFC01CT013"))                    .must(rangequerybuilder))                    .size(100)//如果开启游标，则滚动获取                    .sort("inputtime", SortOrder.ASC);            //查询            SearchRequest request = Requests.searchRequest("pointdata");                request.scroll("2m");                request.source(sourceBuilder);            SearchResponse response = client.search(request).actionGet();            //TODO:处理数据            SearchHits hits = response.getHits();            for(int i = 0; i < hits.getHits().length; i++) {                //System.out.println(hits.getHits()[i].getSourceAsString());                result.add(hits.getHits()[i].getSourceAsString());            }            //记录滚动ID            scrollId = response.getScrollId();            while(true){                //后续的请求                //scrollId = query.getScollId();                SearchScrollRequestBuilder searchScrollRequestBuilder = client                    .prepareSearchScroll(scrollId);                            // 重新设定滚动时间                            //TimeValue timeValue = new TimeValue(30000);                searchScrollRequestBuilder.setScroll("2m");                // 请求                            SearchResponse response1 = searchScrollRequestBuilder.get();                //TODO:处理数据                SearchHits hits2 = response1.getHits();                if(hits2.getHits().length == 0){                    break;                }                for(int i = 0; i < hits2.getHits().length; i++) {                    result.add(hits2.getHits()[i].getSourceAsString());                }                //下一批处理                scrollId = response1.getScrollId();            }            System.out.println(result.size());            long endTime = System.currentTimeMillis();            System.out.println("Java程序运行时间：" + (endTime - startTime) + "ms");        }catch(Exception e){            e.printStackTrace();        }    }