Java 操作RestHighLevelClient查询详解
Java 操作RestHighLevelClient查询详解
Charge8
于2022-08-30 23:51:55发布
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# Elasticsearch
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Java使用ES查询
Java使用ES聚合查询
Elasticsearch
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根据我之前文章对 ES命令的查询使用，测试索引的文档数据前面文章有提到的。下面我们就通过 RestHighLevelClient来进行查询。
参考官方AP文档：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.17/_search_apis.html
一、高级查询Query DSLElasticsearch高级查询Query DSL：https://blog.csdn.net/qq_42402854/article/details/125357445
1、查询接口的步骤一个查询接口的基本步骤如下：
1、创建 SearchRequest搜索请求 创建 SearchRequest 搜索请求，如果不带参数，表示查询所有索引 2、创建 SearchSourceBuilder条件构造 创建 SearchSourceBuilder条件构造，构建搜索的条件。 添加大部分查询参数到 SearchSourceBuilder，还可以接收 QueryBuilders构建的查询参数。 3、将 SearchSourceBuilder 添加到 SearchRequest中 4、执行查询 5、解析查询结果其中，第二步和第五步最为关键。
下面直接上代码，语法使用就不解释了。
2、查询所有match_all使用 match_all，默认只会返回 10条数据。
2.1 全量查询 @Test public void testMatchAll() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求 SearchRequest searchRequest = new SearchRequest(); searchRequest.indices("db_idx4");//指定要查询的索引 //2.创建 SearchSourceBuilder条件构造。builder模式这里就先不简写了 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); MatchAllQueryBuilder matchAllQueryBuilder = QueryBuilders.matchAllQuery(); searchSourceBuilder.query(matchAllQueryBuilder); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println(searchResponse); System.out.println("花费的时长：" + searchResponse.getTook()); SearchHits hits = searchResponse.getHits(); System.out.println(hits.getTotalHits()); System.out.println("符合条件的总文档数量：" + hits.getTotalHits().value); hits.forEach(p -> System.out.println("文档原生信息：" + p.getSourceAsString())); } 2.2 分页查询 size 关键字：指定查询结果中返回指定条数。 默认返回值10条。from 关键字：用来指定起始返回位置，和size关键字连用可实现分页效果 @Test public void testMatchAllPage() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求 SearchRequest searchRequest = new SearchRequest(); searchRequest.indices("db_idx4");//指定要查询的索引 //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder() .query(QueryBuilders.matchAllQuery()); //设置分页 searchSourceBuilder.from(1); searchSourceBuilder.size(5); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的总文档数量：" + hits.getTotalHits().value); hits.forEach(p -> System.out.println("文档原生信息：" + p.getSourceAsString())); } 3、数据排序 @Test public void testSortByAge() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求 SearchRequest searchRequest = new SearchRequest(); searchRequest.indices("db_idx4");//指定要查询的索引 //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder() .query(QueryBuilders.matchAllQuery()); //年龄倒序 searchSourceBuilder.sort("age", SortOrder.DESC); searchSourceBuilder.sort("id", SortOrder.DESC); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的总文档数量：" + hits.getTotalHits().value); hits.forEach(p -> System.out.println("文档原生信息：" + p.getSourceAsString())); } 4、数据过滤数据过滤就是 返回我们指定的字段。
@Test public void testSource() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求 SearchRequest searchRequest = new SearchRequest(); searchRequest.indices("db_idx4");//指定要查询的索引 //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder() .query(QueryBuilders.matchAllQuery()); //指定需要返回或者排除的字段 String[] includes = {"id", "name"}; String[] excludes = {}; searchSourceBuilder.fetchSource(includes, excludes); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的总文档数量：" + hits.getTotalHits().value); hits.forEach(p -> System.out.println("文档原生信息：" + p.getSourceAsString())); } 5、match 查找match在匹配时会对所查找的关键词进行分词，然后按分词匹配查找。
@Test public void testMatch() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("db_idx4"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //match 查找 MatchQueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("address", "王者打野"); matchQueryBuilder.operator(Operator.OR); searchSourceBuilder.query(matchQueryBuilder); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的总文档数量：" + hits.getTotalHits().value); hits.forEach(p -> System.out.println("文档原生信息：" + p.getSourceAsString())); } 6、多字段查询multi_matchmulti_match 关键字：可以根据字段类型，决定是否使用分词查询，得分最高的在前面。
@Test public void testMultiMatch() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("db_idx4"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //MultiMatch 查找 MultiMatchQueryBuilder multiMatchQuery = QueryBuilders.multiMatchQuery("王者辅助","address", "desc"); multiMatchQuery.operator(Operator.OR); searchSourceBuilder.query(multiMatchQuery); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的总文档数量：" + hits.getTotalHits().value); hits.forEach(p -> System.out.println("文档原生信息：" + p.getSourceAsString())); } 7、精确查询Term //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //Term 查找 //TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery("age", 23); TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery("address.keyword", "三国演义小乔"); searchSourceBuilder.query(termQueryBuilder); 8、范围查询range //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //Range 查找 RangeQueryBuilder rangeQueryBuilder = QueryBuilders.rangeQuery("age"); rangeQueryBuilder.gte(18); rangeQueryBuilder.lt(23); searchSourceBuilder.query(rangeQueryBuilder); 9、日期查询range //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("product"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //日期Range 查找 RangeQueryBuilder rangeQueryBuilder = QueryBuilders.rangeQuery("date"); //date字段 rangeQueryBuilder.lt("now‐2y"); searchSourceBuilder.query(rangeQueryBuilder); 10、多个id查询 //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //多个id 查找 IdsQueryBuilder idsQueryBuilder = QueryBuilders.idsQuery(); idsQueryBuilder.addIds("2", "5", "1111"); searchSourceBuilder.query(idsQueryBuilder); 11、高亮查询 @Test public void testHighlight() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("db_idx4"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //Term 查找 TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery("address", "王者"); searchSourceBuilder.query(termQueryBuilder); //自定义高亮 查找 HighlightBuilder highlightBuilder = new HighlightBuilder(); highlightBuilder.preTags("<font color='red'>"); highlightBuilder.postTags("</font>"); highlightBuilder.field("address"); highlightBuilder.requireFieldMatch(false); //多字段时，需要设置为false highlightBuilder.field("desc"); searchSourceBuilder.highlighter(highlightBuilder); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的总文档数量：" + hits.getTotalHits().value); hits.forEach(p -> { System.out.println("文档原生信息：" + p.getSourceAsString()); System.out.println("高亮信息：" + p.getHighlightFields()); }); } 12、布尔查询Bool //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //Bool查找 BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery(); // and //boolQueryBuilder.must(QueryBuilders.rangeQuery("age").gte(20)); //boolQueryBuilder.must(QueryBuilders.matchQuery("sex", "0")); // or boolQueryBuilder.should(QueryBuilders.rangeQuery("age").gte(20)); boolQueryBuilder.should(QueryBuilders.matchQuery("sex", "0")); searchSourceBuilder.query(boolQueryBuilder); 13、模糊查询 //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //Fuzzy 查找 FuzzyQueryBuilder fuzzyQueryBuilder = QueryBuilders.fuzzyQuery("name", "张").fuzziness(Fuzziness.ONE); searchSourceBuilder.query(fuzzyQueryBuilder); 二、聚合操作ElasticSearch聚合操作：https://blog.csdn.net/qq_42402854/article/details/125377293
1、Metric AggregationMetric Aggregation 一些数学运算，可以对文档字段进行统计分析。
1.1 查询员工的最低最高和平均工资 @Test public void testAgg1() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("employees"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //查询员工的最低最高和平均工资 MaxAggregationBuilder maxAggregationBuilder = AggregationBuilders.max("maxSalary").field("salary"); MinAggregationBuilder minAggregationBuilder = AggregationBuilders.min("minSalary").field("salary"); AvgAggregationBuilder avgAggregationBuilder = AggregationBuilders.avg("avgSalary").field("salary"); searchSourceBuilder.aggregation(maxAggregationBuilder); searchSourceBuilder.aggregation(minAggregationBuilder); searchSourceBuilder.aggregation(avgAggregationBuilder); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println(searchResponse); System.out.println("花费的时长：" + searchResponse.getTook()); Aggregations aggregations = searchResponse.getAggregations(); System.out.println("aggregations：" + aggregations); ParsedMax maxSalary = aggregations.get("maxSalary"); ParsedMin minSalary = aggregations.get("minSalary"); ParsedAvg avgSalary = aggregations.get("avgSalary"); System.out.println("maxSalary：" + maxSalary); System.out.println("最低工资" + maxSalary.getValue()); System.out.println("最高工资" + minSalary.getValue()); System.out.println("平均工资" + avgSalary.getValue()); } 1.2 对salary进行统计 @Test public void testAgg2() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("employees"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //对salary进行统计 StatsAggregationBuilder statsAggregationBuilder = AggregationBuilders.stats("statSalary").field("salary"); searchSourceBuilder.aggregation(statsAggregationBuilder); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); Aggregations aggregations = searchResponse.getAggregations(); System.out.println("aggregations：" + aggregations); ParsedStats statSalary = aggregations.get("statSalary"); System.out.println("统计个数" + statSalary.getCount()); System.out.println("平均工资" + statSalary.getAvg()); System.out.println("最高工资" + statSalary.getMaxAsString()); //可以转String System.out.println("最低工资" + statSalary.getMin()); System.out.println("工资之和" + statSalary.getSum()); } 1.3 cardinate对搜索结果去重统计 @Test public void testAgg3() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("employees"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //cardinate对搜索结果去重统计 CardinalityAggregationBuilder cardinalityAggregationBuilder = AggregationBuilders.cardinality("jobCardinate").field("job.keyword"); searchSourceBuilder.aggregation(cardinalityAggregationBuilder); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); Aggregations aggregations = searchResponse.getAggregations(); System.out.println("aggregations：" + aggregations); ParsedCardinality cardinality = aggregations.get("jobCardinate"); System.out.println("字段：" + cardinality.getName()); System.out.println("不重复的个数" + cardinality.getValue()); } 2、Bucket AggregationBucket Aggregation：按照一定的规则，将文档分配到不同的桶中，每一个桶关联一个 key，从而达到分类的目的。类比Mysql中的group by操作。
2.1 获取 job的分类信息 @Test public void testAgg4() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("employees"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); //获取 job的分类信息 TermsAggregationBuilder termsAggregationBuilder = AggregationBuilders.terms("jobGroup").field("job.keyword"); searchSourceBuilder.aggregation(termsAggregationBuilder); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); Aggregations aggregations = searchResponse.getAggregations(); System.out.println("aggregations：" + aggregations); ParsedTerms jobGroup = aggregations.get("jobGroup"); System.out.println("字段：" + jobGroup.getName()); List<? extends Terms.Bucket> buckets = jobGroup.getBuckets(); for (Terms.Bucket bucket : buckets) { System.out.println("getKey：" + bucket.getKey()); System.out.println("getKeyAsString：" + bucket.getKeyAsString()); System.out.println("getDocCount：" + bucket.getDocCount()); } } 2.2 限定聚合范围 @Test public void testAgg5() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("employees"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); RangeQueryBuilder rangeQueryBuilder = QueryBuilders.rangeQuery("salary").gte(10000); searchSourceBuilder.query(rangeQueryBuilder); //获取 job的分类信息 TermsAggregationBuilder termsAggregationBuilder = AggregationBuilders.terms("jobGroup") .field("job.keyword") .size(10) .order(BucketOrder.aggregation("_count", true)); searchSourceBuilder.aggregation(termsAggregationBuilder); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的总文档数量：" + hits.getTotalHits().value); //聚合信息 Aggregations aggregations = searchResponse.getAggregations(); System.out.println("aggregations：" + aggregations); ParsedTerms jobGroup = aggregations.get("jobGroup"); System.out.println("字段：" + jobGroup.getName()); List<? extends Terms.Bucket> buckets = jobGroup.getBuckets(); for (Terms.Bucket bucket : buckets) { System.out.println("getKey：" + bucket.getKey()); System.out.println("getKeyAsString：" + bucket.getKeyAsString()); System.out.println("getDocCount：" + bucket.getDocCount()); } } 2.3 Range 示例：按照工资的 Range 分桶 @Test public void testAgg6() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("employees"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); // Salary Range分桶，可以自己定义 key RangeAggregationBuilder rangeAggregationBuilder = AggregationBuilders.range("salary_range") .field("salary") .addUnboundedTo(10000) .addRange(10000, 20000) .addUnboundedFrom(">20000", 20000); searchSourceBuilder.aggregation(rangeAggregationBuilder); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的总文档数量：" + hits.getTotalHits().value); //聚合信息 Aggregations aggregations = searchResponse.getAggregations(); System.out.println("aggregations：" + aggregations); ParsedRange salaryRange = aggregations.get("salary_range"); //注意类型 System.out.println("字段：" + salaryRange.getName()); List<? extends Range.Bucket> buckets = salaryRange.getBuckets(); for (Range.Bucket bucket : buckets) { System.out.println("getKey：" + bucket.getKey()); System.out.println("getKeyAsString：" + bucket.getKeyAsString()); System.out.println("getDocCount：" + bucket.getDocCount()); System.out.println("getFromAsString：" + bucket.getFromAsString()); System.out.println("getToAsString：" + bucket.getToAsString()); } } 2.4 Histogram示例：按照工资的间隔分桶 // Histogram示例：按照工资的间隔分桶 HistogramAggregationBuilder histogramAggregationBuilder = AggregationBuilders.histogram("salary_histrogram") .field("salary") .interval(5000) .extendedBounds(0, 100000); searchSourceBuilder.aggregation(histogramAggregationBuilder); .5 date_histogram 根据年月日做统计和上面类似，可自定义时间格式 2.6 top_hits示例：top_hits应用场景：当获取分桶后，桶内最匹配的顶部文档列表。
@Test public void testAgg8() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("employees"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); // top_hits示例：指定size，不同工种中，年纪最大的3个员工的具体信息 TopHitsAggregationBuilder topHitsAggregationBuilder = AggregationBuilders.topHits("old_employee") .size(3) .sort("age", SortOrder.DESC); TermsAggregationBuilder termsAggregationBuilder = AggregationBuilders.terms("jobs") .field("job.keyword") .subAggregation(topHitsAggregationBuilder); //嵌套聚合 searchSourceBuilder.aggregation(termsAggregationBuilder); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的总文档数量：" + hits.getTotalHits().value); //聚合信息 Aggregations aggregations = searchResponse.getAggregations(); System.out.println("aggregations：" + aggregations); ParsedTerms jobs = aggregations.get("jobs"); //注意类型 System.out.println("字段：" + jobs.getName()); List<? extends Terms.Bucket> buckets = jobs.getBuckets(); for (Terms.Bucket bucket : buckets) { System.out.println("getKey：" + bucket.getKey()); System.out.println("getKeyAsString：" + bucket.getKeyAsString()); System.out.println("getDocCount：" + bucket.getDocCount()); //嵌套的信息 ParsedTopHits oldEmployee = bucket.getAggregations().get("old_employee"); SearchHits employeeHits = oldEmployee.getHits(); System.out.println(" hits.getTotalHits().value：" + hits.getTotalHits().value); for (SearchHit employeeHit : employeeHits) { System.out.println(" employeeHit.getSourceAsString()：" + employeeHit.getSourceAsString()); } } } 3、Pipeline AggregationPipeline Aggregation：支持对聚合分析的结果，再次进行聚合分析。
3.1 min_bucket示例：最小值在员工数最多的工种里，找出平均工资最低的工种
public void testAgg9() throws IOException { RestHighLevelClient restHighLevelClient = ESUtil.getRestHighLevelClient(); //1.创建 SearchRequest搜索请求,并指定要查询的索引 SearchRequest searchRequest = new SearchRequest("employees"); //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); // min_bucket示例：平均工资最低的工种 AvgAggregationBuilder avgAggregationBuilder = AggregationBuilders.avg("avg_salary").field("salary"); TermsAggregationBuilder termsAggregationBuilder = AggregationBuilders.terms("jobs") .field("job.keyword") .size(10) .subAggregation(avgAggregationBuilder); //嵌套聚合 searchSourceBuilder.aggregation(termsAggregationBuilder); // 添加 bucket pipeline(min_bucket) searchSourceBuilder.aggregation(new MinBucketPipelineAggregationBuilder("min_salary_by_job", "jobs>avg_salary")); //3.将 SearchSourceBuilder 添加到 SearchRequest中 searchRequest.source(searchSourceBuilder); //4.执行查询 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //5.解析查询结果 System.out.println("花费的时长：" + searchResponse.getTook()); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的总文档数量：" + hits.getTotalHits().value); //聚合信息 Aggregations aggregations = searchResponse.getAggregations(); System.out.println("aggregations：" + aggregations); ParsedTerms jobs = aggregations.get("jobs"); //注意类型 System.out.println("字段：" + jobs.getName()); List<? extends Terms.Bucket> buckets = jobs.getBuckets(); for (Terms.Bucket bucket : buckets) { System.out.println("getKey：" + bucket.getKey()); System.out.println("getKeyAsString：" + bucket.getKeyAsString()); System.out.println("getDocCount：" + bucket.getDocCount()); //嵌套的信息 ParsedAvg avgSalary = bucket.getAggregations().get("avg_salary"); System.out.println(" hits.getTotalHits().value：" + avgSalary.getValue()); } } 3.2 Stats示例：统计分析 //2.创建 SearchSourceBuilder条件构造。 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); // Stats示例：统计分析：平均工资的统计分析 AvgAggregationBuilder avgAggregationBuilder = AggregationBuilders.avg("avg_salary").field("salary"); TermsAggregationBuilder termsAggregationBuilder = AggregationBuilders.terms("jobs") .field("job.keyword") .size(10) .subAggregation(avgAggregationBuilder); //嵌套聚合 searchSourceBuilder.aggregation(termsAggregationBuilder); // 添加 bucket pipeline(stats_bucket) searchSourceBuilder.aggregation(new StatsBucketPipelineAggregationBuilder("stats_salary_by_job", "jobs>avg_salary"));到此，Java 操作 RestHighLevelClient查询基本就 ok了。
总结如下：
写好 ES语句很关键，然后通过 客户端编写出来就简单了。创建 SearchSourceBuilder条件构造，构建搜索的条件很重要，根据业务构造r条件变化多端。不管是 Query DSL还是 聚合操作，通过 ES语句的结果来编写 SearchResponse的解析查询结果就很容易了，注意里边的类型。– 求知若饥，虚心若愚。