Java API 方式操作 Elasticsearch

准备项目

创建 Maven 项目，在 IDEA 开发工具中创建 Maven 项目（模块）, 取名叫 es。

修改 pom 文件，增加 Maven 依赖关系

<dependencies>
    <dependency>
        <groupId>org.elasticsearch</groupId>
        <artifactId>elasticsearch</artifactId>
        <version>7.8.0</version>
    </dependency>
    <!-- elasticsearch 的客户端 -->
    <dependency>
        <groupId>org.elasticsearch.client</groupId>
        <artifactId>elasticsearch-rest-high-level-client</artifactId>
        <version>7.8.0</version>
    </dependency>
    <!-- elasticsearch 依赖 2.x 的 log4j -->
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-api</artifactId>
        <version>2.8.2</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-core</artifactId>
        <version>2.8.2</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.9.9</version>
    </dependency>
    <!-- junit 单元测试 -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
</dependencies>

REST 客户端

ES 提供了两个 JAVA REST client 版本
- Java Low Level REST Client: 低级别的 REST 客户端，通过 http 与集群交互，用户需自己编组请求 JSON 串，及解析响应 JSON 串。兼容所有 ES 版本。
- Java High Level REST Client: 高级别的 REST 客户端，基于低级别的 REST 客户端，增加了编组请求 JSON 串、解析响应 JSON 串等相关 api。使用的版本需要保持和 ES 服务端的版本一致，否则会有版本问题。

Low Level Client

High Level Client

从 6.0.0 开始加入的，目的是以 java 面向对象的方式来进行请求、响应处理。
每个 API 支持同步/异步两种方式，同步方法直接返回一个结果对象。异步的方法以 async 为后缀，通过 listener 参数来通知结果。
API 及用法示例参考：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high-supported-apis.html
兼容性说明：
- 依赖 java1.8 和 Elasticsearch core project
- 请使用与服务端 ES 版本一致的客户端版本

使用

创建 pers.fulsun.es.test._01_ESClient 类，代码中创建 Elasticsearch 客户端对象

初始化：给定集群的多个节点地址，将客户端负载均衡地向这个节点地址集发请求：

public class _01_ESClient  {

    public static RestHighLevelClient getClient() {

        RestHighLevelClient client = new RestHighLevelClient(
            RestClient.builder(
                // 9200 端口为 Elasticsearch 默认的 Web 通信端口
                new HttpHost("localhost", 9200, "http"),
                new HttpHost("localhost", 9201, "http")
            )
        );
        return client;
    }
}

Client 不再使用了，记得关闭它：

public static void main(String[] args) throws IOException {
    RestHighLevelClient client = getClient();
    System.out.println(client);
    // 关闭客户端连接
    client.close();
}

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

创建索引

代码如下：

import java.io.IOException;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.indices.CreateIndexRequest;
import org.elasticsearch.client.indices.CreateIndexResponse;
import pers.fulsun.es.test._01_ESClient;

public class _01_ESTest_Index_Create {
    private static RestHighLevelClient client= _01_ESClient.getClient();;

    public static void main(String[] args) throws IOException {
        // 创建索引 - 请求对象
        CreateIndexRequest request = new CreateIndexRequest("user1");
        // 发送请求，获取响应
        CreateIndexResponse response = client.indices().create(request, RequestOptions.DEFAULT);
        boolean acknowledged = response.isAcknowledged();
        // 响应状态
        System.out.println("操作状态 = " + acknowledged);
        // 关闭客户端连接
        client.close();
    }
}

操作结果：
1
操作状态 = true

查找索引

代码如下：


import java.io.IOException;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.indices.GetIndexRequest;
import org.elasticsearch.client.indices.GetIndexResponse;
import pers.fulsun.es.test._01_ESClient;

public class _02_ESTest_Index_Search {
    private static RestHighLevelClient client = _01_ESClient.getClient();

    public static void main(String[] args) throws IOException {
        // 创建索引 - 请求对象
        GetIndexRequest request = new GetIndexRequest("user");
        // 发送请求，获取响应
        GetIndexResponse getIndexResponse = client.indices().get(request, RequestOptions.DEFAULT);
        // 响应状态
        System.out.println(getIndexResponse.getAliases());
        System.out.println(getIndexResponse.getMappings());
        System.out.println(getIndexResponse.getSettings());
        // 关闭客户端连接
        client.close();
    }
}

操作结果：

1
2
3

{user=[]}
{user=org.elasticsearch.cluster.metadata.MappingMetadata@90ad7867}
{user={"index.creation_date":"1637398010230","index.number_of_replicas":"1","index.number_of_shards":"1","index.provided_name":"user","index.uuid":"cG5E6L9jR8OwFiAXe0lNrw","index.version.created":"7080099"}}

删除索引

代码如下：

public class _03_ESTest_Index_Delete {
    private static RestHighLevelClient client = _01_ESClient.getClient();

    public static void main(String[] args) throws IOException {
        // 删除索引 - 请求对象
        DeleteIndexRequest request = new DeleteIndexRequest("user");
        // 发送请求，获取响应
        AcknowledgedResponse response = client.indices().delete(request, RequestOptions.DEFAULT);
        // 响应状态
        System.out.println(response.isAcknowledged());
        // 关闭客户端连接
        client.close();
    }
}

操作结果：
1
true

文档操作

创建数据模型

添加 lombok 依赖

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.20</version>
</dependency>

创建实体类

@Data
public class User {
  private String name;
  private String sex;
  private Integer age;
}

新增文档

代码如下：

package pers.fulsun.es.test._03_doc;

import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.IOException;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;
import pers.fulsun.es.test._01_ESClient;
import pers.fulsun.es.test.entity.User;

public class _01_ESTest_Doc_Insert {
    private static RestHighLevelClient client = _01_ESClient.getClient();

    public static void main(String[] args) throws IOException {
        // 新增文档 - 请求对象
        IndexRequest request = new IndexRequest();
        // 设置索引及唯一性标识
        request.index("user").id("1001");
        // 创建数据对象
        User user = new User();
        user.setName("zhangsan");
        user.setAge(30);
        user.setSex("男");
        ObjectMapper objectMapper = new ObjectMapper();
        String productJson = objectMapper.writeValueAsString(user);
        // 添加文档数据，数据格式为 JSON 格式
        request.source(productJson, XContentType.JSON);
        // 客户端发送请求，获取响应对象
        IndexResponse response = client.index(request, RequestOptions.DEFAULT);
        //// 3. 打印结果信息
        System.out.println("_index:" + response.getIndex());
        System.out.println("_id:" + response.getId());
        System.out.println("_result:" + response.getResult());
        // 关闭客户端连接
        client.close();
    }
}

操作结果：
1
2
3
_index:user
_id:1001
_result:CREATED

修改文档

代码如下：

package pers.fulsun.es.test._03_doc;

import java.io.IOException;
import org.elasticsearch.action.update.UpdateRequest;
import org.elasticsearch.action.update.UpdateResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;
import pers.fulsun.es.test._01_ESClient;

public class _02_ESTest_Doc_Update {
    private static RestHighLevelClient client = _01_ESClient.getClient();

    public static void main(String[] args) throws IOException {
        // 修改文档 - 请求对象
        UpdateRequest request = new UpdateRequest();
        // 配置修改参数
        request.index("user").id("1001");
        // 设置请求体，对数据进行修改
        request.doc(XContentType.JSON, "sex", "女");
        // 添加文档数据，数据格式为 JSON 格式
        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
        // 客户端发送请求，获取响应对象
        //// 3. 打印结果信息
        System.out.println("_index:" + response.getIndex());
        System.out.println("_id:" + response.getId());
        System.out.println("_result:" + response.getResult());
        // 关闭客户端连接
        client.close();
    }
}

操作结果：
1
2
3
_index:user
_id:1001
_result:UPDATED

查询文档

代码如下：

public class _03_ESTest_Doc_Search {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    GetRequest request = new GetRequest();
    request.index("user").id("1004");

    GetResponse response = client.get(request, RequestOptions.DEFAULT);
    System.out.println(response.isExists());
    System.out.println(response.getSourceAsString());

    // 关闭客户端连接
    client.close();
  }
}

操作结果：

1 2	true {"name":"wangwu1","age":40,"sex":"女"}

删除文档

代码如下：

public class _04_ESTest_Doc_Delete {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {

    DeleteRequest request = new DeleteRequest();
    request.index("user").id("1001");

    DeleteResponse response = client.delete(request, RequestOptions.DEFAULT);
    System.out.println(response.toString());

    // 关闭客户端连接
    client.close();
  }
}

操作结果：

1	DeleteResponse[index=user,type=_doc,id=1001,version=3,result=deleted,shards=ShardInfo{total=2, successful=1, failures=[]}]

批量插入

代码如下：

public class _05_ESTest_Doc_Insert_Batch {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {

    // 批量插入数据
    BulkRequest request = new BulkRequest();
    request.add(new IndexRequest().index("user").id("1001").source(XContentType.JSON, "name", "zhangsan", "age",30,"sex","男"));
    request.add(new IndexRequest().index("user").id("1002").source(XContentType.JSON, "name", "lisi", "age",30,"sex","女"));
    request.add(new IndexRequest().index("user").id("1003").source(XContentType.JSON, "name", "wangwu", "age",40,"sex","男"));
    request.add(new IndexRequest().index("user").id("1004").source(XContentType.JSON, "name", "wangwu1", "age",40,"sex","女"));
    request.add(new IndexRequest().index("user").id("1005").source(XContentType.JSON, "name", "wangwu2", "age",50,"sex","男"));
    request.add(new IndexRequest().index("user").id("1006").source(XContentType.JSON, "name", "wangwu3", "age",50,"sex","男"));
    request.add(new IndexRequest().index("user").id("1007").source(XContentType.JSON, "name", "wangwu44", "age",60,"sex","男"));
    request.add(new IndexRequest().index("user").id("1008").source(XContentType.JSON, "name", "wangwu555", "age",60,"sex","男"));
    request.add(new IndexRequest().index("user").id("1009").source(XContentType.JSON, "name", "wangwu66666", "age",60,"sex","男"));

    BulkResponse response = client.bulk(request, RequestOptions.DEFAULT);
    System.out.println(response.getTook());
    System.out.println(response.getItems());
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

1 2	180ms [Lorg.elasticsearch.action.bulk.BulkItemResponse;@4b1d6571

批量删除

代码如下：

public class _06_ESTest_Doc_Delete_Batch {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 批量删除数据
    BulkRequest request = new BulkRequest();

    request.add(new DeleteRequest().index("user").id("1001"));
    request.add(new DeleteRequest().index("user").id("1002"));
    request.add(new DeleteRequest().index("user").id("1003"));

    BulkResponse response = client.bulk(request, RequestOptions.DEFAULT);
    System.out.println(response.getTook());
    System.out.println(response.getItems());

    // 关闭客户端连接
    client.close();
  }
}

操作结果：

1 2	175ms [Lorg.elasticsearch.action.bulk.BulkItemResponse;@1a20270e

高级查询

查询所有索引数据

QueryBuilders.matchAllQuery())代码如下：

package pers.fulsun.es.test._04_search;

import java.io.IOException;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import pers.fulsun.es.test._01_ESClient;

public class _01_ESTest_Doc_Search_All {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 1. 查询索引的所有数据
    SearchRequest request = new SearchRequest();
    request.indices("user");

    // 构造查询条件
    SearchSourceBuilder builder = new SearchSourceBuilder();
    builder.query(QueryBuilders.matchAllQuery());

    // 添加查询条件到请求
    request.source(builder);
    // 发起查询
    SearchResponse response = client.search(request, RequestOptions.DEFAULT);

    // 查询匹配
    SearchHits hits = response.getHits();
    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("total:" + hits.getTotalHits());
    System.out.println("MaxScore:" + hits.getMaxScore());
    System.out.println("hits========>>");
    for (SearchHit hit : hits) {
      // 输出每条查询的结果信息
       System.out.println(hit.getSourceAsString());
    }
    System.out.println("<<========");
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

took:1ms
timeout:false
total:6 hits
MaxScore:1.0
hits========>>
{"name":"wangwu1","age":40,"sex":"女"}
{"name":"wangwu2","age":50,"sex":"男"}
{"name":"wangwu3","age":50,"sex":"男"}
{"name":"wangwu44","age":60,"sex":"男"}
{"name":"wangwu555","age":60,"sex":"男"}
{"name":"wangwu66666","age":60,"sex":"男"}
<<========

关键字查询

term 查询QueryBuilders.termQuery(...))，代码如下：

public class _02_ESTest_Doc_Search_Term {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 创建搜索请求对象
    SearchRequest request = new SearchRequest();
    request.indices("user");

    // 构建查询的请求体
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
    // text 类型的中文可以使用 keyword 避免分词
    sourceBuilder.query(QueryBuilders.termQuery("name.keyword", "wangwu3"));
    request.source(sourceBuilder);

    SearchResponse response = client.search(request, RequestOptions.DEFAULT);
    // 查询匹配
    SearchHits hits = response.getHits();
    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("total:" + hits.getTotalHits());
    System.out.println("MaxScore:" + hits.getMaxScore());
    System.out.println("hits========>>");
    for (SearchHit hit : hits) {
      // 输出每条查询的结果信息
      System.out.println(hit.getSourceAsString());
    }
    System.out.println("<<========");
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

took:3ms
timeout:false
total:1 hits
MaxScore:1.89712
hits========>>
{"name":"wangwu3","age":50,"sex":"男"}
<<========

分页查询

代码如下：

public class _03_ESTest_Doc_Search_Page {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 创建搜索请求对象
    SearchRequest request = new SearchRequest();
    request.indices("user");

    // 构建查询的请求体
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
    sourceBuilder.query(QueryBuilders.matchAllQuery());

    // 分页查询
    // 当前页其实索引（第一条数据的顺序号为 0)
    sourceBuilder.from(0);
    // 每页显示多少条 size
    sourceBuilder.size(2);

    request.source(sourceBuilder);

    SearchResponse response = client.search(request, RequestOptions.DEFAULT);
    // 查询匹配
    SearchHits hits = response.getHits();
    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("total:" + hits.getTotalHits());
    System.out.println("MaxScore:" + hits.getMaxScore());
    System.out.println("hits========>>");
    for (SearchHit hit : hits) {
      // 输出每条查询的结果信息
      System.out.println(hit.getSourceAsString());
    }
    System.out.println("<<========");
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

took:1ms
timeout:false
total:6 hits
MaxScore:1.0
hits========>>
{"name":"wangwu1","age":40,"sex":"女"}
{"name":"wangwu2","age":50,"sex":"男"}
<<========

数据排序

代码如下：

public class _04_ESTest_Doc_Search_Sort {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 创建搜索请求对象
    SearchRequest request = new SearchRequest();
    request.indices("user");

    // 构建查询的请求体
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
    sourceBuilder.query(QueryBuilders.matchAllQuery());

    // 排序
    sourceBuilder.sort("age", SortOrder.ASC);

    request.source(sourceBuilder);

    SearchResponse response = client.search(request, RequestOptions.DEFAULT);
    // 查询匹配
    SearchHits hits = response.getHits();
    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("total:" + hits.getTotalHits());
    System.out.println("MaxScore:" + hits.getMaxScore());
    System.out.println("hits========>>");
    for (SearchHit hit : hits) {
      // 输出每条查询的结果信息
      System.out.println(hit.getSourceAsString());
    }
    System.out.println("<<========");
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

took:25ms
timeout:false
total:6 hits
MaxScore:NaN
hits========>>
{"name":"wangwu1","age":40,"sex":"女"}
{"name":"wangwu2","age":50,"sex":"男"}
{"name":"wangwu3","age":50,"sex":"男"}
{"name":"wangwu44","age":60,"sex":"男"}
{"name":"wangwu555","age":60,"sex":"男"}
{"name":"wangwu66666","age":60,"sex":"男"}
<<========

过滤字段

代码如下：

public class _05_ESTest_Doc_Search_Filter {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 创建搜索请求对象
    SearchRequest request = new SearchRequest();
    request.indices("user");

    // 构建查询的请求体
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
    sourceBuilder.query(QueryBuilders.matchAllQuery());

    // 查询字段过滤
    String[] excludes = {"age"};
    String[] includes = {"name", "age"};
    sourceBuilder.fetchSource(includes, excludes);

    request.source(sourceBuilder);

    SearchResponse response = client.search(request, RequestOptions.DEFAULT);
    // 查询匹配
    SearchHits hits = response.getHits();
    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("total:" + hits.getTotalHits());
    System.out.println("MaxScore:" + hits.getMaxScore());
    System.out.println("hits========>>");
    for (SearchHit hit : hits) {
      // 输出每条查询的结果信息
      System.out.println(hit.getSourceAsString());
    }
    System.out.println("<<========");
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

took:1ms
timeout:false
total:6 hits
MaxScore:1.0
hits========>>
{"name":"wangwu1"}
{"name":"wangwu2"}
{"name":"wangwu3"}
{"name":"wangwu44"}
{"name":"wangwu555"}
{"name":"wangwu66666"}
<<========

组合 (Bool) 查询

代码如下：

public class _06_ESTest_Doc_Search_Bool {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 创建搜索请求对象
    SearchRequest request = new SearchRequest();
    request.indices("user");

    // 构建查询的请求体
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

    BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
    // 必须包含
    boolQueryBuilder.must(QueryBuilders.matchQuery("age", "60"));
    // 一定不含
    // boolQueryBuilder.mustNot(QueryBuilders.matchQuery("name", "wangwu66666"));
    // 可能包含
    boolQueryBuilder.should(QueryBuilders.termQuery("sex", "女"));
    boolQueryBuilder.should(QueryBuilders.termQuery("name.keyword", "wangwu44"));
    // 只有 must 和 should 会失效，满足任意一个 should 即可
    boolQueryBuilder.minimumShouldMatch(1);

    sourceBuilder.query(boolQueryBuilder);

    request.source(sourceBuilder);

    SearchResponse response = client.search(request, RequestOptions.DEFAULT);
    // 查询匹配
    SearchHits hits = response.getHits();
    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("total:" + hits.getTotalHits());
    System.out.println("MaxScore:" + hits.getMaxScore());
    System.out.println("hits========>>");
    for (SearchHit hit : hits) {
      // 输出每条查询的结果信息
      System.out.println(hit.getSourceAsString());
    }
    System.out.println("<<========");
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

took:2ms
timeout:false
total:2 hits
MaxScore:2.5404449
hits========>>
{"name":"wangwu44","age":60,"sex":"男"}
{"name":"wangwu555","age":60,"sex":"女"}
<<========

范围查询

代码如下：

public class _07_ESTest_Doc_Search_Range {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 创建搜索请求对象
    SearchRequest request = new SearchRequest();
    request.indices("user");

    // 构建查询的请求体
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

    RangeQueryBuilder rangeQuery = QueryBuilders.rangeQuery("age");
    // 大于等于
    rangeQuery.gte("30");
    // 小于等于
    rangeQuery.lte("40");

    sourceBuilder.query(rangeQuery);
    request.source(sourceBuilder);

    SearchResponse response = client.search(request, RequestOptions.DEFAULT);
    // 查询匹配
    SearchHits hits = response.getHits();
    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("total:" + hits.getTotalHits());
    System.out.println("MaxScore:" + hits.getMaxScore());
    System.out.println("hits========>>");
    for (SearchHit hit : hits) {
      // 输出每条查询的结果信息
      System.out.println(hit.getSourceAsString());
    }
    System.out.println("<<========");
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

took:3ms
timeout:false
total:1 hits
MaxScore:1.0
hits========>>
{"name":"wangwu1","age":40,"sex":"女"}
<<========

模糊查询

代码如下：

public class _08_ESTest_Doc_Search_Fuzzy {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 创建搜索请求对象
    SearchRequest request = new SearchRequest();
    request.indices("user");

    // 构建查询的请求体
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
    sourceBuilder.query(QueryBuilders.fuzzyQuery("name", "wangwu").fuzziness(Fuzziness.TWO));
    request.source(sourceBuilder);

    SearchResponse response = client.search(request, RequestOptions.DEFAULT);
    // 查询匹配
    SearchHits hits = response.getHits();
    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("total:" + hits.getTotalHits());
    System.out.println("MaxScore:" + hits.getMaxScore());
    System.out.println("hits========>>");
    for (SearchHit hit : hits) {
      // 输出每条查询的结果信息
      System.out.println(hit.getSourceAsString());
    }
    System.out.println("<<========");
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

took:4ms
timeout:false
total:4 hits
MaxScore:1.2837042
hits========>>
{"name":"wangwu1","age":40,"sex":"女"}
{"name":"wangwu2","age":50,"sex":"男"}
{"name":"wangwu3","age":50,"sex":"男"}
{"name":"wangwu44","age":60,"sex":"男"}
<<========

高亮查询

代码如下：

public class _09_ESTest_Doc_Search_HighLight {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 创建搜索请求对象
    SearchRequest request = new SearchRequest();
    request.indices("user");

    // 构建查询的请求体
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();

    // 构建查询方式
    TermsQueryBuilder termsQueryBuilder = QueryBuilders.termsQuery("name", "wangwu1");
    sourceBuilder.query(termsQueryBuilder);

    // 构建高亮字段
    HighlightBuilder highlightBuilder = new HighlightBuilder();
    // 设置标签前缀
    highlightBuilder.preTags("<font color='red'>");
    // 设置标签后缀
    highlightBuilder.postTags("</font>");
    // 设置高亮字段
    highlightBuilder.field("name");
    // 设置高亮构建对象
    sourceBuilder.highlighter(highlightBuilder);

    request.source(sourceBuilder);

    SearchResponse response = client.search(request, RequestOptions.DEFAULT);
    // 查询匹配
    SearchHits hits = response.getHits();
    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("total:" + hits.getTotalHits());
    System.out.println("MaxScore:" + hits.getMaxScore());
    System.out.println("hits========>>");
    for (SearchHit hit : hits) {
      // 输出每条查询的结果信息
      System.out.println(hit.getSourceAsString());
      // 打印高亮结果
      Map<String, HighlightField> highlightFields = hit.getHighlightFields();
      System.out.println(highlightFields);
    }
    System.out.println("<<========");
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

took:3ms
timeout:false
total:1 hits
MaxScore:1.0
hits========>>
{"name":"wangwu1","age":40,"sex":"女"}
{name=[name], fragments[[<font color='red'>wangwu1</font>]]}
<<========

聚合查询

聚合操作分为指标聚合和分组聚合。RestHighLevelClient 可以使用 API 方法也可以使用 script 脚本进行聚合。

最大年龄

代码如下：

public class _010_ESTest_Doc_Search_Max {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 构建查询的请求体
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
    // 构建聚合查询方式
    sourceBuilder.aggregation(AggregationBuilders.max("maxAge").field("age"));

    // 创建搜索请求对象
    SearchRequest request = new SearchRequest();
    request.indices("user");
    sourceBuilder.size(0);
    request.source(sourceBuilder);

    SearchResponse response = client.search(request, RequestOptions.DEFAULT);

    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("aggregations========>>");
    // 和之前不同的是这里需要 getAggregations 获取聚合后的数据
    Aggregations aggregations = response.getAggregations();
    //从查询结果中获取刚才定义的最大值的名称
    Max maxAge = aggregations.get("maxAge");
    System.out.println(maxAge.getValue());
    System.out.println("<<========");
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

took:2ms
timeout:false
aggregations========>>
60.0
<<========

stats 聚合

stats 聚合，对某个字段一次性返回 count，max，min，avg 和 sum 五个指标

代码如下：

import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.aggregations.Aggregations;
import org.elasticsearch.search.aggregations.metrics.Stats;
public class _010_ESTest_Doc_Search_Stats {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 构建查询的请求体
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
    // 构建聚合查询方式
    sourceBuilder.aggregation(AggregationBuilders.stats("stats_age").field("age"));

    // 创建搜索请求对象
    SearchRequest request = new SearchRequest();
    request.indices("user");
    sourceBuilder.size(0);
    request.source(sourceBuilder);

    SearchResponse response = client.search(request, RequestOptions.DEFAULT);

    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("aggregations========>>");
    // 和之前不同的是这里需要 getAggregations 获取聚合后的数据
    Aggregations aggregations = response.getAggregations();
    //从查询结果中获取刚才定义的最大值的名称
    Stats stats = aggregations.get("stats_age");
    System.out.println("count:"+stats.getCount());
    System.out.println("min:"+stats.getMin());
    System.out.println("max:"+stats.getMax());
    System.out.println("avg:"+stats.getAvg());
    System.out.println("sum:"+stats.getSum());
    System.out.println("<<========");
    // 关闭客户端连接
    client.close();
  }
}

操作结果：

took:1ms
timeout:false
aggregations========>>
count:6
min:40.0
max:60.0
avg:53.333333333333336
sum:320.0
<<========took:1ms
timeout:false
aggregations========>>
count:6
min:40.0
max:60.0
avg:53.333333333333336
sum:320.0
<<========

分组统计

代码如下：

public class _011_ESTest_Doc_Search_Group {
  private static RestHighLevelClient client = _01_ESClient.getClient();

  public static void main(String[] args) throws IOException {
    // 构建查询的请求体
    SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
    // 构建聚合查询方式
    TermsAggregationBuilder aggregationBuilder = AggregationBuilders
        .terms("age_tr").field("age").                   //桶分组
        //求总数：可以从结果获取
        // subAggregation(AggregationBuilders.count("count_age").field("age")).
        subAggregation(AggregationBuilders.sum("sum_age").field("age")).  //求和
        subAggregation(AggregationBuilders.avg("avg_age").field("age")); //求平均值
    sourceBuilder.aggregation(aggregationBuilder);

    // 创建搜索请求对象
    SearchRequest request = new SearchRequest();
    // 不输出原始数据
    sourceBuilder.size(0);
    //  打印 dsl 语句
    System.out.println(("dsl:" + sourceBuilder.toString()));
    // 设置索引以及填充语句
    request.indices("user");
    request.source(sourceBuilder);
    // 发送请求
    SearchResponse response = client.search(request, RequestOptions.DEFAULT);

    System.out.println("took:" + response.getTook());
    System.out.println("timeout:" + response.isTimedOut());
    System.out.println("aggregations========>>");
    // 和之前不同的是这里需要 getAggregations 获取聚合后的数据
    Aggregations aggregations = response.getAggregations();
    //ParsedTerms 有 long double String 三种类型
    ParsedLongTerms parsedStringTerms = aggregations.get("age_tr");
    List<? extends Bucket> buckets = parsedStringTerms.getBuckets();
    for (Terms.Bucket bucket : buckets) {
      //key 的数据
      String key = bucket.getKey().toString();
      // 分组的数据 = count
      long docCount = bucket.getDocCount();
      //获取数据
      Aggregations bucketAggregations = bucket.getAggregations();
     // long count = ((ParsedValueCount) bucketAggregations.get("count_age")).getValue();
      ParsedSum sum = bucketAggregations.get("sum_age");
      ParsedAvg avg = bucketAggregations.get("avg_age");
      System.out.println(
          key + ": count:"
              + docCount + ", sum:"
              + sum.getValue() +  ", avg:"
              + avg.getValue());
    }

    // 关闭客户端连接
    client.close();
  }
}

操作结果：

dsl:{"size":0,"aggregations":{"age_tr":{"terms":{"field":"age","size":10,"min_doc_count":1,"shard_min_doc_count":0,"show_term_doc_count_error":false,"order":[{"_count":"desc"},{"_key":"asc"}]},"aggregations":{"sum_age":{"sum":{"field":"age"}},"avg_age":{"avg":{"field":"age"}}}}}}
took:4ms
timeout:false
aggregations========>>
60: count:3, sum:180.0, avg:60.0
50: count:2, sum:100.0, avg:50.0
40: count:1, sum:40.0, avg:40.0