Elasticsearch 6.1 TransportClient實現多條件重排序搜索查詢之FilterFunctionBuilder和FunctionScoreQueryBuilder

搜索條件：在Index爲10000下查找標題包含“IPhone”,優先取“品牌手機”這個分類，銷量越高越前，結果隨機給用戶展示：
JAVA 代碼實現片段：

		String searchContent = "IPhone";
        TransportClient client = esClient.getTransportClient();
        String index = "10000";
        SearchRequestBuilder searchBuilder = client.prepareSearch(index);
        //分頁
        searchBuilder.setFrom(0).setSize(10);
        //explain爲true表示根據數據相關度排序，和關鍵字匹配最高的排在前面
        searchBuilder.setExplain(true);

        BoolQueryBuilder queryBuilder = QueryBuilders.boolQuery();
        // 搜索 title字段包含IPhone的數據
        queryBuilder.must(QueryBuilders.matchQuery("title", searchContent));

        FunctionScoreQueryBuilder.FilterFunctionBuilder[] filterFunctionBuilders = new FunctionScoreQueryBuilder.FilterFunctionBuilder[3];

        //過濾條件1：分類爲：品牌手機最重要 -- 權重查詢Weight
        ScoreFunctionBuilder<WeightBuilder> scoreFunctionBuilder = new WeightBuilder();
        scoreFunctionBuilder.setWeight(2);
        QueryBuilder termQuery = QueryBuilders.termQuery("categoryName", "品牌手機");
        FunctionScoreQueryBuilder.FilterFunctionBuilder category = new FunctionScoreQueryBuilder.FilterFunctionBuilder(termQuery, scoreFunctionBuilder);
        filterFunctionBuilders[0] = category;

        // 過濾條件2：銷量越高越排前 --計分查詢 FieldValueFactor
        ScoreFunctionBuilder<FieldValueFactorFunctionBuilder> fieldValueScoreFunction = new FieldValueFactorFunctionBuilder("salesVolume");
        ((FieldValueFactorFunctionBuilder) fieldValueScoreFunction).factor(1.2f);
        FunctionScoreQueryBuilder.FilterFunctionBuilder sales = new FunctionScoreQueryBuilder.FilterFunctionBuilder(fieldValueScoreFunction);
        filterFunctionBuilders[1] = sales;

        // 給定每個用戶隨機展示：  --random_score
        ScoreFunctionBuilder<RandomScoreFunctionBuilder> randomScoreFilter = new RandomScoreFunctionBuilder();
        ((RandomScoreFunctionBuilder) randomScoreFilter).seed(2);
        FunctionScoreQueryBuilder.FilterFunctionBuilder random = new FunctionScoreQueryBuilder.FilterFunctionBuilder(randomScoreFilter);
        filterFunctionBuilders[2] = random;

        // 多條件查詢 FunctionScore
        FunctionScoreQueryBuilder query = QueryBuilders.functionScoreQuery(queryBuilder, filterFunctionBuilders)
                .scoreMode(FunctionScoreQuery.ScoreMode.SUM).boostMode(CombineFunction.SUM);
        searchBuilder.setQuery(query);

        SearchResponse response = searchBuilder.execute().actionGet();
        SearchHits hits = response.getHits();
        String searchSource;
        for (SearchHit hit : hits)
        {
            searchSource = hit.getSourceAsString();
            System.out.println(searchSource);
        }
        //        long took = response.getTook().getMillis();
        long total = hits.getTotalHits();
        System.out.println(total);

演示代碼地址：GitHub