es_分組-分頁-TransportClient實現

說在前面：

Elasticsearch Java API 有四種實現方式：分別是 TransportClient、RestClient、Jest、Spring Data Elasticsearch。
本文使用第一種方式，也就是 TransportClient 的方式進行實現。想要了解其餘三種的方式能夠看一下這篇文章：https://blog.csdn.net/qq_3331...

總結：

一、group 以後不能自動分頁，須要手動設置；

二、size 須要指定，不然會出錯。

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group 以後分頁、排序實現

須要手動截取分頁對應範圍內的數據。

好比：這裏

倒序，獲取到數據集的第 (currentPage-1) limit 到 currentPage limit 條記錄；

升序，獲取到數據集的 第 buckets.size() - (currentPage - 1) limit 到 buckets.size() - currentPage limit 條記錄。

// 獲取到 response 以後
Aggregations aggregations = response.getAggregations();
Terms carids =  aggregations.get("group_car_bayId");
List<? extends Terms.Bucket> buckets =  carids.getBuckets();
List<carBean> listCarTgs = new ArrayList<>();
carBean carBean ;
// buckets 所有數據，分頁就是取固定位置的 limit 條數據
// 默認按照統計以後的數量倒序， 若是要正序，則第一頁從最後一條開始取
if(buckets.size()>0) {
    int i=0;
    if("desc".equalsIgnoreCase(order)) {// 倒序
        for(Terms.Bucket bucket : buckets){
            if(i++<(currentPage-1) * limit){
                continue;
            }
            if (i > currentPage * limit) {
                break;
            }
            carBean = new carBean();
            carBean.setPassTimes((int)bucket.getDocCount());
            carBean.setBayId(bucket.getKeyAsString().split("_")[2]);
            carBean.setPlateNumber(bucket.getKeyAsString().split("_")[0]);
            carBean.setPlateType(bucket.getKeyAsString().split("_")[1]);
            listCarTgs.add(carBean);
        }
    }else if("asc".equalsIgnoreCase(order)) {// 升序
        for(i = buckets.size() - 1; i >= 0; i--){
            if(i < buckets.size() - currentPage * limit){
                break;
            }
            if(i > buckets.size() - (currentPage - 1) * limit) continue;;
            carBean = new carBean();
            carBean.setPassTimes((int)buckets.get(i).getDocCount());
            carBean.setBayId(buckets.get(i).getKeyAsString().split("_")[2]);
            carBean.setPlateNumber(buckets.get(i).getKeyAsString().split("_")[0]);
            carBean.setPlateType(buckets.get(i).getKeyAsString().split("_")[1]);
            listCarTgs.add(carBean);
        }
    }
}

單個 group

注意：須要設置 size

TermsAggregationBuilder tb=  AggregationBuilders.terms("group_bayId").field("bay_id").size(Integer.MAX_VALUE);

多個 group

以腳本的形式

TermsAggregationBuilder tb=  AggregationBuilders.terms("group_carId").script(new Script("doc['plateNumber'].value+'_'+doc['plateType'].value"));
            tb.subAggregation(AggregationBuilders.topHits("max_time").sort("reportTime", SortOrder.DESC).size(1));

再好比：三個 group

BoolQueryBuilder filter = QueryBuilders.boolQuery();
if (carList != null && carList.size() >0) {
    filter.must(QueryBuilders.termsQuery("car_plate_number", carList.stream().map(SimpleCar:: getPlateNumber).collect(Collectors.toList())));
}
if (startTime != null && endTime != null) {
    filter.filter(QueryBuilders.rangeQuery("timestamp").gt(startTime.getTime()).lt(endTime.getTime()));
} else if (startTime != null) {
    filter.filter(QueryBuilders.rangeQuery("timestamp").gt(startTime.getTime()));
} else if (endTime != null) {
    filter.filter(QueryBuilders.rangeQuery("timestamp").lt(endTime.getTime()));
}
FieldSortBuilder sort = SortBuilders.fieldSort("transit_times").order("asc".equalsIgnoreCase(order)?SortOrder.ASC:SortOrder.DESC);
TermsAggregationBuilder termsAggregationBuilder =  AggregationBuilders.terms("group_car_bayId")
        .script(new Script("doc['car_plate_number'].value+'_'+doc['car_plate_type'].value + '_' +doc['bay_id'].value")).size(Integer.MAX_VALUE);
SearchResponse response = search(filter, sort, termsAggregationBuilder, elasticsearchProperties.getTgsIndex(), elasticsearchProperties.getTgsType(),
        (currentPage-1) * limit, 0);
Aggregations aggregations = response.getAggregations();

例子2：

TermsAggregationBuilder tb=  AggregationBuilders.terms("group_bayId").field("bay_id").size(Integer.MAX_VALUE);
    tb.order(BucketOrder.count(false));