38.如何使用java实现scroll？嘻哈的简写笔记——Elastic Search

@Test //深分页Scroll
public void test22() throws IOException {
        //Java实现scroll分页
        //1. 创建SearchRequest
        SearchRequest request = new SearchRequest(indextName);
        request.types(typeName);

        //2. 指定scroll信息
        request.scroll(TimeValue.timeValueMinutes(1L));

        //3. 指定查询条件
        SearchSourceBuilder builder = new SearchSourceBuilder();
        builder.size(4);
        builder.sort("price", SortOrder.DESC);
        builder.query(QueryBuilders.matchAllQuery());

        request.source(builder);

        //4. 获取返回结果scrollId，source
        SearchResponse resp = ClientUtils.client().search(request, RequestOptions.DEFAULT);

        String scrollId = resp.getScrollId();
        System.out.println("----------首页---------");
        for (SearchHit hit : resp.getHits().getHits()) {
            System.out.println(hit.getSourceAsMap());
        }
        //java也是一样要查询两次，先把我们的首页给查询出来；
        //查询出来之后我们要获取他的id
        //然后利用他的id去查询他的下一页
        while(true) {
            //5. 循环 - 创建SearchScrollRequest
            SearchScrollRequest scrollRequest = new SearchScrollRequest(scrollId);//在这里获取id去查下一页；

            //6. 指定scrollId的生存时间
            scrollRequest.scroll(TimeValue.timeValueMinutes(1L));

            //7. 执行查询获取返回结果
            SearchResponse scrollResp = ClientUtils.client().scroll(scrollRequest, RequestOptions.DEFAULT);

            //8. 判断是否查询到了数据，输出
            SearchHit[] hits = scrollResp.getHits().getHits();
            //循环输出下一页
            if(hits != null && hits.length > 0) {
                System.out.println("----------下一页---------");
                for (SearchHit hit : hits) {
                    System.out.println(hit.getSourceAsMap());
                }
            }else{
                //9. 判断没有查询到数据-退出循环
                System.out.println("----------结束---------");
                break;
            }
        }

        //查完之后我们把存进缓存的id给删除；
        //10. 创建CLearScrollRequest
        ClearScrollRequest clearScrollRequest = new ClearScrollRequest();

        //11. 指定ScrollId
        clearScrollRequest.addScrollId(scrollId);

        //12. 删除ScrollId
        ClearScrollResponse clearScrollResponse = ClientUtils.client().clearScroll(clearScrollRequest, RequestOptions.DEFAULT);

        //13. 输出结果
        System.out.println("删除scroll：" + clearScrollResponse.isSucceeded());
}