1、场景引入

queryForList默认查询10条每次，最多可设置为10000条，意味着该api最多只能查询10000条数数据
elasticsearchTemplate.queryForList(query, ComparisonPlatformGoodsItemSearchView.class);

类似同步之类的逻辑，es特定的业务索引几百万乃至上千万的数据，显然，仅仅通过elasticsearchTemplate.queryForList(）是无法满足的。

2、解决方案：

第一种：通过scroll（类似mysql游标）

官方手册：https://docs.spring.io/spring-data/elasticsearch/docs/current/reference/html/#elasticsearch.scroll

（注意：spring-data-elasticsearch不同版本api名称不一样，4.x.x和3.x.x存在不一样，诸如：searchScrollStart/scrollStart、searchScrollContinue/scrollContinue等）

代码示例：

public void createPurchaseActivityConfigurationGoodsSearchData(PurchaseActivityConfiguration paramBean) {
        BoolQueryBuilder boolQuery = QueryBuilders.boolQuery()
                .must(QueryBuilders.matchQuery("brandId", paramBean.getBrandId()))
                .must(QueryBuilders.matchQuery("comparisonCategoryId", paramBean.getCategoryId()));

        NativeSearchQuery query = new NativeSearchQueryBuilder().withQuery(boolQuery).build();
        List<ComparisonPlatformGoodsItemSearchView> goodsItemViews = new ArrayList<>();


        ScrolledPage scroll = elasticsearchTemplate.startScroll(SCROLL_TIME, query, ComparisonPlatformGoodsItemSearchView.class);
        while (scroll.hasContent()) {
            goodsItemViews.addAll(scroll.getContent());
            scroll = elasticsearchTemplate.continueScroll(scroll.getScrollId(), SCROLL_TIME, ComparisonPlatformGoodsItemSearchView.class);
        }
        elasticsearchTemplate.clearScroll(scroll.getScrollId());



        if (ObjectUtil.isNotNull(paramBean.getCommissionRatioThreshold())) {
            purchaseHighSubsidyGoodsSearchRepository.saveAll(covertPurchaseHighSubsidyGoodsSearchView(goodsItemViews));
            log.info(">>>>>> createPurchaseHighSubsidyGoodsSearchData success");
        }
    }

第二种：通过Stream