Elasticsearch软件是由Java语言开发的，所以也可以通过Java API的方式对Elasticsearch服务进行访问

1、创建 Maven 项目

在 IDEA 开发工具中创建 Maven 项目(模块也可)ES

四、Java API操作 - 图1

  • 修改 pom 文件，增加 Maven 依赖关系
  1. <dependencies>
  2.     <dependency>
  3.         <groupId>org.elasticsearch</groupId>
  4.         <artifactId>elasticsearch</artifactId>
  5.         <version>7.8.0</version>
  6.     </dependency>
  7.     <!-- elasticsearch 的客户端 -->
  8.     <dependency>
  9.         <groupId>org.elasticsearch.client</groupId>
  10.         <artifactId>elasticsearch-rest-high-level-client</artifactId>
  11.         <version>7.8.0</version>
  12.     </dependency>
  13.     <!-- elasticsearch 依赖 2.x 的 log4j -->
  14.     <dependency>
  15.         <groupId>org.apache.logging.log4j</groupId>
  16.         <artifactId>log4j-api</artifactId>
  17.         <version>2.8.2</version>
  18.     </dependency>
  19.     <dependency>
  20.         <groupId>org.apache.logging.log4j</groupId>
  21.         <artifactId>log4j-core</artifactId>
  22.         <version>2.8.2</version>
  23.     </dependency>
  24.     <dependency>
  25.         <groupId>com.fasterxml.jackson.core</groupId>
  26.         <artifactId>jackson-databind</artifactId>
  27.         <version>2.9.9</version>
  28.     </dependency>
  29.     <!-- junit 单元测试 -->
  30.     <dependency>
  31.         <groupId>junit</groupId>
  32.         <artifactId>junit</artifactId>
  33.         <version>4.12</version>
  34.     </dependency>
  35. </dependencies>

2、客户端对象

四、Java API操作 - 图2

因为早期版本的客户端对象已经不再推荐使用，且在未来版本中会被删除，所以这里我们采用高级 REST 客户端对象

  1. public static void main(String[] args) throws IOException {
  2.     //创建ES客户端
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  8.     //关闭ES客户端
  9.     esClient.close();
  11. }

注意：9200 端口为 Elasticsearch 的 Web 通信端口 ，localhost 为启动 ES 服务的主机名

执行代码，查看控制台信息：

四、Java API操作 - 图3

3、索引操作

ES 服务器正常启动后，可以通过 Java API 客户端对象对 ES 索引进行操作

3.1、创建索引

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     //创建索引 - 请求对象
  8.     CreateIndexRequest request = new CreateIndexRequest("user");
  9.     //发送请求，获取响应
  10.     CreateIndexResponse response = esClient.indices().create(request, RequestOptions.DEFAULT);
  11.     //响应状态
  12.     boolean acknowledged = response.isAcknowledged();
  13.     System.out.println("索引操作：" + acknowledged);
  16.     esClient.close();
  17. }

四、Java API操作 - 图4

3.2、查看索引

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     //查询索引 - 请求对象
  8.     GetIndexRequest request = new GetIndexRequest("user");
  9.     //发送请求，获取响应
  10.     GetIndexResponse response = esClient.indices().get(request, RequestOptions.DEFAULT);
  12.     System.out.println("aliases:" + response.getAliases());
  13.     System.out.println("mappings:" + response.getMappings());
  14.     System.out.println("settings:" + response.getSettings());
  16.     esClient.close();
  17. }

四、Java API操作 - 图5

3.3、删除索引

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     //删除索引 - 请求对象
  8.     DeleteIndexRequest request = new DeleteIndexRequest("user");
  9.     //发送请求，获取响应
  10.     AcknowledgedResponse response = esClient.indices().delete(request, RequestOptions.DEFAULT);
  11.     //响应状态
  12.     System.out.println("操作结果：" + response.isAcknowledged());
  14.     esClient.close();
  15. }

四、Java API操作 - 图6

4、文档操作

4.1、新增文档

创建数据模型

  1. public class User {
  3.     private String name;
  4.     private Integer age;
  5.     private String sex;
  8.     public String getName() {
  9.         return name;
  10.     }
  12.     public void setName(String name) {
  13.         this.name = name;
  14.     }
  16.     public Integer getAge() {
  17.         return age;
  18.     }
  20.     public void setAge(Integer age) {
  21.         this.age = age;
  22.     }
  24.     public String getSex() {
  25.         return sex;
  26.     }
  28.     public void setSex(String sex) {
  29.         this.sex = sex;
  30.     }
  31. }

创建数据，添加到文档中

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     //新增文档 - 请求对象
  8.     IndexRequest request = new IndexRequest();
  9.     //设置索引及唯一性标识
  10.     request.index("user").id("1001");
  12.     //创建数据对象
  13.     User user = new User();
  14.     user.setName("zhangsan");
  15.     user.setAge(30);
  16.     user.setSex("男");
  17.     //向ES插入数据，必须将数据转换为JSON格式
  18.     ObjectMapper mapper = new ObjectMapper();
  19.     String userJson = mapper.writeValueAsString(user);
  20.     request.source(userJson, XContentType.JSON);
  22.     //客户端发送请求，获取响应对象
  23.     IndexResponse response = esClient.index(request, RequestOptions.DEFAULT);
  25.     System.out.println("_index:" + response.getIndex());
  26.     System.out.println("_id:" + response.getId());
  27.     System.out.println("_result:" + response.getResult());
  30.     esClient.close();
  31. }

四、Java API操作 - 图7

4.2、修改文档

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     //修改文档 - 请求对象
  8.     UpdateRequest request = new UpdateRequest();
  9.     //设置索引及唯一性标识
  10.     request.index("user").id("1001");
  11.     //设置请求体，对数据进行修改
  12.     request.doc(XContentType.JSON, "sex", "女");
  14.     //客户端发送请求，获取响应对象
  15.     UpdateResponse response = esClient.update(request, RequestOptions.DEFAULT);
  17.     System.out.println("_index:" + response.getIndex());
  18.     System.out.println("_id:" + response.getId());
  19.     System.out.println("_result:" + response.getResult());
  22.     esClient.close();
  23. }

四、Java API操作 - 图8

4.3、查询文档

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     //查询文档 - 请求对象
  8.     GetRequest request = new GetRequest();
  9.     //设置索引及唯一性标识
  10.     request.index("user").id("1001");
  12.     //客户端发送请求，获取响应对象
  13.     GetResponse response = esClient.get(request, RequestOptions.DEFAULT);
  15.     System.out.println("_index:" + response.getIndex());
  16.     System.out.println("_type:" + response.getType());
  17.     System.out.println("_id:" + response.getId());
  18.     System.out.println("resource:" + response.getSourceAsString());
  21.     esClient.close();
  22. }

四、Java API操作 - 图9

4.4、删除文档

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     //查询文档 - 请求对象
  8.     DeleteRequest request = new DeleteRequest();
  9.     //设置索引及唯一性标识
  10.     request.index("user").id("1001");
  12.     //客户端发送请求，获取响应对象
  13.     DeleteResponse response = esClient.delete(request, RequestOptions.DEFAULT);
  15.     System.out.println(response.toString());
  17.     esClient.close();
  18. }

四、Java API操作 - 图10

4.5、批量新增

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     //创建批量新增请求对象
  8.     BulkRequest request = new BulkRequest();
  10.     request.add(new IndexRequest().index("user").id("1001").source(XContentType.JSON, "name", "zhangsan"));
  11.     request.add(new IndexRequest().index("user").id("1002").source(XContentType.JSON, "name", "lisi"));
  12.     request.add(new IndexRequest().index("user").id("1003").source(XContentType.JSON, "name", "wangwu"));
  14.     //客户端发送请求，获取响应对象
  15.     BulkResponse responses = esClient.bulk(request, RequestOptions.DEFAULT);
  17.     //打印结果信息
  18.     System.out.println("took:" + responses.getTook());
  19.     System.out.println("items:" + responses.getItems());
  21.     esClient.close();
  22. }

四、Java API操作 - 图11

4.6、批量删除

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     //创建批量删除请求对象
  8.     BulkRequest request = new BulkRequest();
  10.     request.add(new DeleteRequest().index("user").id("1001"));
  11.     request.add(new DeleteRequest().index("user").id("1002"));
  12.     request.add(new DeleteRequest().index("user").id("1003"));
  14.     //客户端发送请求，获取响应对象
  15.     BulkResponse responses = esClient.bulk(request, RequestOptions.DEFAULT);
  17.     //打印结果信息
  18.     System.out.println("took:" + responses.getTook());
  19.     System.out.println("items:" + responses.getItems());
  21.     esClient.close();
  22. }

四、Java API操作 - 图12

5、高级查询

5.1、请求体查询

查询所有索引数据

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     // 创建搜索请求对象
  8.     SearchRequest request = new SearchRequest();
  9.     request.indices("user");
  11.     // 构建查询的请求体
  12.     SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  13.     // 查询所有数据
  14.     searchSourceBuilder.query(QueryBuilders.matchAllQuery());
  15.     request.source(searchSourceBuilder);
  17.     //客户端发送请求，获取响应对象
  18.     SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
  20.     // 查询匹配
  21.     System.out.println("took:" + response.getTook());
  22.     System.out.println("timeout:" + response.isTimedOut());
  23.     SearchHits hits = response.getHits();
  24.     System.out.println("total:" + hits.getTotalHits());
  25.     System.out.println("MaxScore:" + hits.getMaxScore());
  26.     for (SearchHit hit : hits) {
  27.         //输出每条查询的结果信息
  28.         System.out.println(hit.getSourceAsString());
  29.     }
  32.     esClient.close();
  33. }

四、Java API操作 - 图13

term查询，查询条件为关键字

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     // 创建搜索请求对象
  8.     SearchRequest request = new SearchRequest();
  9.     request.indices("user");
  11.     // 构建查询的请求体
  12.     SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  13.     // 条件查询 termQuery
  14.     searchSourceBuilder.query(QueryBuilders.termQuery("age",30));
  15.     request.source(searchSourceBuilder);
  17.     //客户端发送请求，获取响应对象
  18.     SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
  20.     // 查询匹配
  21.     System.out.println("took:" + response.getTook());
  22.     System.out.println("timeout:" + response.isTimedOut());
  23.     SearchHits hits = response.getHits();
  24.     System.out.println("total:" + hits.getTotalHits());
  25.     System.out.println("MaxScore:" + hits.getMaxScore());
  26.     for (SearchHit hit : hits) {
  27.         //输出每条查询的结果信息
  28.         System.out.println(hit.getSourceAsString());
  29.     }
  32.     esClient.close();
  33. }

四、Java API操作 - 图14

分页查询

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     // 创建搜索请求对象
  8.     SearchRequest request = new SearchRequest();
  9.     request.indices("user");
  11.     // 构建查询的请求体
  12.     SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  13.     // 分页查询
  14.     searchSourceBuilder.query(QueryBuilders.matchAllQuery());
  15.     // (当前页码-1)*每页显示数据条数
  16.     searchSourceBuilder.from(4);//第三页
  17.     searchSourceBuilder.size(2);
  18.     request.source(searchSourceBuilder);
  20.     //客户端发送请求，获取响应对象
  21.     SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
  23.     // 查询匹配
  24.     System.out.println("took:" + response.getTook());
  25.     System.out.println("timeout:" + response.isTimedOut());
  26.     SearchHits hits = response.getHits();
  27.     System.out.println("total:" + hits.getTotalHits());
  28.     System.out.println("MaxScore:" + hits.getMaxScore());
  29.     for (SearchHit hit : hits) {
  30.         //输出每条查询的结果信息
  31.         System.out.println(hit.getSourceAsString());
  32.     }
  35.     esClient.close();
  36. }

四、Java API操作 - 图15

数据排序

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     // 创建搜索请求对象
  8.     SearchRequest request = new SearchRequest();
  9.     request.indices("user");
  11.     // 构建查询的请求体
  12.     SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  13.     searchSourceBuilder.query(QueryBuilders.matchAllQuery());
  14.     // 排序
  15.     searchSourceBuilder.sort("age", SortOrder.DESC);
  16.     request.source(searchSourceBuilder);
  18.     //客户端发送请求，获取响应对象
  19.     SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
  21.     // 查询匹配
  22.     System.out.println("took:" + response.getTook());
  23.     System.out.println("timeout:" + response.isTimedOut());
  24.     SearchHits hits = response.getHits();
  25.     System.out.println("total:" + hits.getTotalHits());
  26.     System.out.println("MaxScore:" + hits.getMaxScore());
  27.     for (SearchHit hit : hits) {
  28.         //输出每条查询的结果信息
  29.         System.out.println(hit.getSourceAsString());
  30.     }
  33.     esClient.close();
  34. }

四、Java API操作 - 图16

过滤字段

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     // 创建搜索请求对象
  8.     SearchRequest request = new SearchRequest();
  9.     request.indices("user");
  11.     // 构建查询的请求体
  12.     SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  13.     searchSourceBuilder.query(QueryBuilders.matchAllQuery());
  14.     // 查询字段过滤
  15.     String excludes[] = {};
  16.     String includes[] = {"name"};
  17.     searchSourceBuilder.fetchSource(includes, excludes);
  18.     request.source(searchSourceBuilder);
  20.     //客户端发送请求，获取响应对象
  21.     SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
  23.     // 查询匹配
  24.     System.out.println("took:" + response.getTook());
  25.     System.out.println("timeout:" + response.isTimedOut());
  26.     SearchHits hits = response.getHits();
  27.     System.out.println("total:" + hits.getTotalHits());
  28.     System.out.println("MaxScore:" + hits.getMaxScore());
  29.     for (SearchHit hit : hits) {
  30.         //输出每条查询的结果信息
  31.         System.out.println(hit.getSourceAsString());
  32.     }
  35.     esClient.close();
  36. }

四、Java API操作 - 图17

Bool查询

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     // 创建搜索请求对象
  8.     SearchRequest request = new SearchRequest();
  9.     request.indices("user");
  11.     // 构建查询的请求体
  12.     SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  14.     BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
  15.     // 必须包含
  16.     boolQueryBuilder.must(QueryBuilders.matchQuery("age", "30"));
  17.     // 一定不含
  18.     boolQueryBuilder.mustNot(QueryBuilders.matchQuery("name", "zhangsan"));
  19.     // 可能包含
  20.     boolQueryBuilder.should(QueryBuilders.matchQuery("sex", "男"));
  22.     searchSourceBuilder.query(boolQueryBuilder);
  23.     request.source(searchSourceBuilder);
  25.     //客户端发送请求，获取响应对象
  26.     SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
  28.     // 查询匹配
  29.     System.out.println("took:" + response.getTook());
  30.     System.out.println("timeout:" + response.isTimedOut());
  31.     SearchHits hits = response.getHits();
  32.     System.out.println("total:" + hits.getTotalHits());
  33.     System.out.println("MaxScore:" + hits.getMaxScore());
  34.     for (SearchHit hit : hits) {
  35.         //输出每条查询的结果信息
  36.         System.out.println(hit.getSourceAsString());
  37.     }
  40.     esClient.close();
  41. }

四、Java API操作 - 图18

范围查询

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     // 创建搜索请求对象
  8.     SearchRequest request = new SearchRequest();
  9.     request.indices("user");
  11.     // 构建查询的请求体
  12.     SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  14.     RangeQueryBuilder rangeQuery = QueryBuilders.rangeQuery("age");
  15.     // 大于等于
  16.     rangeQuery.gte("30");
  17.     // 小于等于
  18.     rangeQuery.lte("40");
  20.     searchSourceBuilder.query(rangeQuery);
  21.     request.source(searchSourceBuilder);
  23.     //客户端发送请求，获取响应对象
  24.     SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
  26.     // 查询匹配
  27.     System.out.println("took:" + response.getTook());
  28.     System.out.println("timeout:" + response.isTimedOut());
  29.     SearchHits hits = response.getHits();
  30.     System.out.println("total:" + hits.getTotalHits());
  31.     System.out.println("MaxScore:" + hits.getMaxScore());
  32.     for (SearchHit hit : hits) {
  33.         //输出每条查询的结果信息
  34.         System.out.println(hit.getSourceAsString());
  35.     }
  38.     esClient.close();
  39. }

四、Java API操作 - 图19

模糊查询

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     // 创建搜索请求对象
  8.     SearchRequest request = new SearchRequest();
  9.     request.indices("user");
  11.     // 构建查询的请求体
  12.     SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  14.     FuzzyQueryBuilder fuzziness = QueryBuilders.fuzzyQuery("name", "wangwu").fuzziness(Fuzziness.ONE);
  16.     searchSourceBuilder.query(fuzziness);
  17.     request.source(searchSourceBuilder);
  19.     //客户端发送请求，获取响应对象
  20.     SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
  22.     // 查询匹配
  23.     System.out.println("took:" + response.getTook());
  24.     System.out.println("timeout:" + response.isTimedOut());
  25.     SearchHits hits = response.getHits();
  26.     System.out.println("total:" + hits.getTotalHits());
  27.     System.out.println("MaxScore:" + hits.getMaxScore());
  28.     for (SearchHit hit : hits) {
  29.         //输出每条查询的结果信息
  30.         System.out.println(hit.getSourceAsString());
  31.     }
  34.     esClient.close();
  35. }

四、Java API操作 - 图20

5.2、高亮查询

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     // 创建搜索请求对象
  8.     SearchRequest request = new SearchRequest();
  9.     request.indices("user");
  11.     // 构建查询的请求体
  12.     SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  14.     //构建查询方式：高亮查询
  15.     TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery("name", "zhangsan");
  16.     //设置查询方式
  17.     searchSourceBuilder.query(termQueryBuilder);
  19.     //构建高亮字段
  20.     HighlightBuilder highlightBuilder = new HighlightBuilder();
  21.     highlightBuilder.preTags("<font color='red'>");
  22.     highlightBuilder.postTags("</font>");
  23.     highlightBuilder.field("name");
  24.     //设置高亮对象
  25.     searchSourceBuilder.highlighter(highlightBuilder);
  27.     //设置请求体
  28.     request.source(searchSourceBuilder);
  30.     //客户端发送请求，获取响应对象
  31.     SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
  33.     // 查询匹配
  34.     System.out.println("took:" + response.getTook());
  35.     System.out.println("timeout:" + response.isTimedOut());
  36.     SearchHits hits = response.getHits();
  37.     System.out.println("total:" + hits.getTotalHits());
  38.     System.out.println("MaxScore:" + hits.getMaxScore());
  39.     for (SearchHit hit : hits) {
  40.         //输出每条查询的结果信息
  41.         System.out.println(hit.getSourceAsString());
  42.         //打印高亮结果
  43.         Map<String, HighlightField> highlightFields = hit.getHighlightFields();
  44.         System.out.println(highlightFields);
  45.     }
  48.     esClient.close();
  49. }

四、Java API操作 - 图21

5.3、聚合查询

最大

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.         RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     // 创建搜索请求对象
  8.     SearchRequest request = new SearchRequest();
  9.     request.indices("user");
  11.     // 构建查询的请求体
  12.     SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  14.     //设置查询方式
  15.     AggregationBuilder aggregationBuilder =AggregationBuilders.max("maxAge").field("age");
  16.     searchSourceBuilder.aggregation(aggregationBuilder);
  18.     //设置请求体
  19.     request.source(searchSourceBuilder);
  21.     //客户端发送请求，获取响应对象
  22.     SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
  24.     // 查询匹配
  25.     ObjectMapper mapper = new ObjectMapper();
  27.     Aggregations aggregations = response.getAggregations();
  28.     System.out.println(mapper.writeValueAsString(aggregations));
  30.     Aggregation maxAge = aggregations.getAsMap().get("maxAge");
  31.     System.out.println(mapper.writeValueAsString(maxAge));
  33.     String valueAsString = ((Max) maxAge).getValueAsString();
  34.     System.out.println(valueAsString);
  37.     esClient.close();
  38. }

四、Java API操作 - 图22

分组统计

  1. public static void main(String[] args) throws IOException {
  3.     RestHighLevelClient esClient = new RestHighLevelClient(
  4.             RestClient.builder(new HttpHost("localhost", 9200, "http"))
  5.     );
  7.     // 创建搜索请求对象
  8.     SearchRequest request = new SearchRequest();
  9.     request.indices("user");
  11.     // 构建查询的请求体
  12.     SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
  14.     //设置查询方式
  15.     AggregationBuilder aggregationBuilder =AggregationBuilders.terms("ageGroup").field("age");
  16.     searchSourceBuilder.aggregation(aggregationBuilder);
  18.     //设置请求体
  19.     request.source(searchSourceBuilder);
  21.     //客户端发送请求，获取响应对象
  22.     SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);
  24.     // 查询匹配
  25.     ObjectMapper mapper = new ObjectMapper();
  27.     Aggregations aggregations = response.getAggregations();
  28.     System.out.println(mapper.writeValueAsString(aggregations));
  30.     Aggregation ageGroup = aggregations.getAsMap().get("ageGroup");
  31.     System.out.println(mapper.writeValueAsString(ageGroup));
  33.     List<? extends Terms.Bucket> buckets = ((Terms) ageGroup).getBuckets();
  34.     for (Terms.Bucket bucket : buckets) {
  35.         //分组的key
  36.         String key = bucket.getKeyAsString();
  37.         //分组的值
  38.         long docCount = bucket.getDocCount();
  40.         System.out.println(key+"------"+docCount);
  41.     }
  43.     esClient.close();
  44. }

四、Java API操作 - 图23