README.md · wphgitee/elasticsearch学习实战项目

# Elasticsearch8学习笔记

## 一、安装elasticsearch和kibana

### 1.1.编写elasticsearch.yaml文件

```yaml
# 版本信息：2.2
services:
  # Elasticsearch 服务配置
  Elasticsearch:
    # 镜像名称：elasticsearch:8.12.0
    image: elasticsearch:8.12.0
    # 容器名称：elasticsearch
    container_name: elasticsearch
    # 数据卷挂载
    volumes:
      - /home/docker/container/elasticsearch/data:/usr/share/elasticsearch/data
      - /home/docker/container/elasticsearch/logs:/usr/share/elasticsearch/logs
      - /home/docker/container/elasticsearch/config:/usr/share/elasticsearch/config
      - /home/docker/container/elasticsearch/plugins:/usr/share/elasticsearch/plugins
    # 端口映射：将本地的 9200 端口映射到容器的 9200 端口
    ports:
      - 9200:9200
    # 环境变量设置
    environment:
      - node.name=single-node
      - cluster.name=docker-cluster
      - discovery.type=single-node
      - bootstrap.memory_lock=true
      - xpack.security.enabled=false
    # 内存限制：1GB
    mem_limit: 1g
    # ulimits 设置：解锁内存锁定
    ulimits:
      memlock:
        soft: -1
        hard: -1
    # 健康检查：使用 CMD-SHELL 执行 curl 命令检查 Elasticsearch 是否运行正常
    healthcheck:
      test:
        [
          "CMD-SHELL",
          "curl -s http://localhost:9200 | grep -q 'elasticsearch'",
        ]
      interval: 10s
      timeout: 10s
      retries: 120
  # Kibana 服务配置
  kibana:
    # 依赖 Elasticsearch 服务
    depends_on:
      - elasticsearch
    # 镜像名称：kibana:8.12.0
    image: kibana:8.12.0
    # 容器名称：kibana
    container_name: kibana
    # 数据卷挂载
    volumes:
      - /home/docker/container/kibana/data:/usr/share/kibana/data
      - /home/docker/container/kibana/logs:/usr/share/kibana/logs
      - /home/docker/container/kibana/config:/usr/share/kibana/config
      - /home/docker/container/kibana/plugins:/usr/share/kibana/plugins
    # 端口映射：将本地的 5601 端口映射到容器的 5601 端口
    ports:
      - 5601:5601
    # 环境变量设置
    environment:
      - SERVERNAME=kibana
      - ELASTICSEARCH_HOSTS=http://elasticsearch:9200
    # 内存限制：1GB
    mem_limit: 1g
    # 健康检查：使用 CMD-SHELL 执行 curl 命令检查 Kibana 是否运行正常
    healthcheck:
      test:
        [
          "CMD-SHELL",
          "curl -s -I http://localhost:5601 | grep -q 'HTTP/1.1 302 Found'",
        ]
      interval: 10s
      timeout: 10s
      retries: 120
```

### 1.2.安装ik分词器

[下载地址](https://github.com/medcl/elasticsearch-analysis-ik/releases)

解压后重命名放入以下位置

### 1.3.启动容器命令

```shell
docker compose -f elasticsearch.yaml up -d
```

### 1.4.启动效果（portainer控制台）

![image-20240219090420463](assets/image-20240219090420463.png)

## 二、springboot整合elasticsearch8.x

### 2.1.springboot项目引入依赖

```xml
<dependency>
    <groupId>co.elastic.clients</groupId>
    <artifactId>elasticsearch-java</artifactId>
</dependency>
```

### 2.2.配置客户端

#### 2.2.1.application.yaml定义参数

```yaml
elasticsearch:
  host: 192.168.120.130
  port: 9200
```

#### 2.2.2.java代码中配置

```java
@Configuration
public class EsConfig {

@Value("${elasticsearch.host}")
    private String hostname;

@Value("${elasticsearch.port}")
    private int port;

/**
     * 创建一个ElasticsearchClient实例，并将其注册为Bean。
     * @return ElasticsearchClient实例
     */
    @Bean
    public ElasticsearchClient elasticsearchClient() {
        // 创建一个HttpHost实例，用于指定Elasticsearch的主机和端口
        HttpHost httpHost = HttpHost.create(hostname + ":" + port);
        // 创建一个RestClient实例，用于与Elasticsearch进行通信
        RestClient restClient = RestClient.builder(httpHost).build();
        // 创建一个RestClientTransport实例，用于将RestClient与Elasticsearch连接起来
        RestClientTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        // 创建一个ElasticsearchClient实例，并传入RestClientTransport对象
        return new ElasticsearchClient(transport);
    }

/**
     * 创建一个ElasticsearchAsyncClient实例，并将其注册为Bean。
     * @return ElasticsearchAsyncClient实例
     */
    @Bean
    public ElasticsearchAsyncClient elasticsearchAsyncClient() {
        // 创建一个HttpHost实例，用于指定Elasticsearch的主机和端口
        HttpHost httpHost = HttpHost.create(hostname + ":" + port);
        // 创建一个RestClient实例，用于与Elasticsearch进行通信
        RestClient restClient = RestClient.builder(httpHost).build();
        // 创建一个RestClientTransport实例，用于将RestClient与Elasticsearch连接起来
        RestClientTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
        // 创建一个ElasticsearchAsyncClient实例，并传入RestClientTransport对象
        return new ElasticsearchAsyncClient(transport);
    }

}
```

### 2.3.代码中引入客户端

```java
@Autowired
private ElasticsearchClient client;
```

## 三、RestAPI

### 3.1.创建索引库

#### 3.1.1.方式一

- 编写some-index.json文件放到src/main/resources目录下

```json
{
  "mappings": {
    "properties": {
      "id": {
        "type": "keyword"
      },
      "name": {
        "type": "text",
        "analyzer": "ik_max_word",
        "copy_to": "all"
      },
      "address": {
        "type": "keyword",
        "index": false
      },
      "price": {
        "type": "integer"
      },
      "score": {
        "type": "integer"
      },
      "brand": {
        "type": "keyword",
        "copy_to": "all"
      },
      "city": {
        "type": "keyword",
        "copy_to": "all"
      },
      "starName": {
        "type": "keyword"
      },
      "business": {
        "type": "keyword"
      },
      "location": {
        "type": "geo_point"
      },
      "pic": {
        "type": "keyword",
        "index": false
      },
      "all": {
        "type": "text",
        "analyzer": "ik_max_word"
      }
    }
  }
}
```

- 创建文档类型实体类HotelDoc.java

```java
@Data
@NoArgsConstructor
@AllArgsConstructor
public class HotelDoc {
    @Schema(description = "酒店id")
    private Long id;
    @Schema(description = "酒店名称")
    private String name;
    @Schema(description = "酒店地址")
    private String address;
    @Schema(description = "酒店价格")
    private Integer price;
    @Schema(description = "酒店评分")
    private Integer score;
    @Schema(description = "酒店品牌")
    private String brand;
    @Schema(description = "酒店城市")
    private String city;
    @Schema(description = "酒店星级")
    private String starName;
    @Schema(description = "酒店商圈")
    private String business;
    @Schema(description = "酒店经纬度")
    private String location;
    @Schema(description = "酒店图片")
    private String pic;
    // 排序时的 距离值
    @Schema(description = "距离值")
    private Object distance;
    @Schema(description = "是否广告位")
    private Boolean isAD;
    @Schema(description = "建议词")
    private List<String> suggestion;

public HotelDoc(Hotel hotel) {
        this.id = hotel.getId();
        this.name = hotel.getName();
        this.address = hotel.getAddress();
        this.price = hotel.getPrice();
        this.score = hotel.getScore();
        this.brand = hotel.getBrand();
        this.city = hotel.getCity();
        this.starName = hotel.getStarName();
        this.business = hotel.getBusiness();
        this.location = hotel.getLatitude() + ", " + hotel.getLongitude();
        this.pic = hotel.getPic();
		final String regex = "[\\u4e00-\\u9fa5]+";
        final Pattern pattern = Pattern.compile(regex);
        if (hotel.getBusiness().isEmpty()) {
            this.suggestion = Arrays.asList(this.brand);
        } else {
            this.suggestion = new ArrayList<>();
            this.suggestion.add(this.brand);
            Matcher matcher = pattern.matcher(hotel.getBusiness());
            while (matcher.find()) {
                this.suggestion.add(matcher.group());
            }
        }
    }
}
```

- 编写java代码

```java
/**
 * 测试创建索引
 * @throws IOException
 */
@Test
public void createIndex1() throws IOException {
    // 创建一个InputStream对象，用于读取索引配置文件
    InputStream input = new FileInputStream(new File("src/main/resources/some-index.json"));

// 创建一个CreateIndexRequest对象，用于指定索引名称和索引配置文件
    CreateIndexRequest req = CreateIndexRequest.of(b -> b
            .index("some-index")
            .withJson(input)
    );

// 调用Elasticsearch客户端的create方法创建索引，并获取返回结果
    boolean created = client.indices().create(req).acknowledged();

// 根据创建结果输出相应的信息
    if (created) {
        System.out.println("创建成功");
    } else {
        System.out.println("创建失败");
    }
}
```

#### 3.1.2.方式二

- 编写java类HotelIndexConsts.java

```java
public class HotelIndexConsts {
    public static final String MAPPING_TEMPLATE = """
            {
              "mappings": {
                "properties": {
                  "id": {
                    "type": "keyword"
                  },
                  "name": {
                    "type": "text",
                    "analyzer": "ik_max_word",
                    "copy_to": "all"
                  },
                  "address": {
                    "type": "keyword",
                    "index": false
                  },
                  "price": {
                    "type": "integer"
                  },
                  "score": {
                    "type": "integer"
                  },
                  "brand": {
                    "type": "keyword",
                    "copy_to": "all"
                  },
                  "city": {
                    "type": "keyword",
                    "copy_to": "all"
                  },
                  "starName": {
                    "type": "keyword"
                  },
                  "business": {
                    "type": "keyword"
                  },
                  "location": {
                    "type": "geo_point"
                  },
                  "pic": {
                    "type": "keyword",
                    "index": false
                  },
                  "all": {
                    "type": "text",
                    "analyzer": "ik_max_word"
                  }
                }
              }
            }
            
            
            
            """;
}
```

- 编写java代码

```java
@Test
public void createIndex2() throws IOException {
    //创建Reader
    Reader reader = new StringReader(HotelIndexConsts.MAPPING_TEMPLATE);
    CreateIndexRequest req = CreateIndexRequest.of(b -> b
            .index("some-index")
            .withJson(reader)
    );

boolean created = client.indices().create(req).acknowledged();
    if (created) {
        System.out.println("创建成功");
    } else {
        System.out.println("创建失败");
    }
}
```

### 3.2.删除索引库

```java
@Test
public void deleteIndex() throws IOException {
    // 创建删除索引请求
    DeleteIndexRequest request = DeleteIndexRequest.of(b -> b.index("some-index"));
    // 发送删除索引请求并获取响应
    DeleteIndexResponse response = client.indices().delete(request);
    // 判断删除是否成功
    if (response.acknowledged()) {
        System.out.println("删除成功");
    } else {
        System.out.println("删除失败");
    }
}
```

### 3.3.判断索引是否存在

```java
@Test
public void testExistsIndex() throws IOException {
    // 创建ExistsRequest对象，指定要查询的索引库名称
    ExistsRequest request = ExistsRequest.of(b -> b.index("hotel"));
    // 发送查询请求，获取索引库是否存在
    BooleanResponse response = client.indices().exists(request);
    // 输出查询结果
    System.out.println(response.value()?"索引存在":"索引不存在");
}
```

## 四、操作文档

### 4.1.新增文档

```java
@Test
public void testAddDocument() throws IOException {
    // 1. 根据id查询酒店数据
    Hotel hotel = hotelService.getById(61083L);
    // 2. 将酒店数据转换为文档类型（HotelDoc）
    HotelDoc hotelDoc = new HotelDoc(hotel);
    // 3. 将HotelDoc对象转换为JSON格式字符串
    String json = JSON.toJSONString(hotelDoc);
    // 4. 准备索引请求对象
    IndexResponse response = client.index(i -> i
            .index("hotel") // 设置索引名称为"hotel"
            .id(hotelDoc.getId().toString()) // 设置文档id
            .document(hotelDoc) // 设置待索引的文档对象
    );
    log.info("已成功索引，版本号为：" + response.version());
}
```

### 4.2.查询文档

```java
@Test
public void getIndex() throws IOException {
    // 1. 准备GetIndexRequest对象
    GetIndexRequest request = GetIndexRequest.of(b -> b.index("hotel"));
    // 2. 准备并发送获取请求，获取响应对象(GetResponse)
    GetResponse<HotelDoc> getResponse = client.get(i -> i.index("hotel").id("61083"), HotelDoc.class);
    // 3. 从响应对象中获取原始文档数据（HotelDoc类型）
    HotelDoc hotelDoc = getResponse.source();
    // 4. 打印获取到的HotelDoc对象内容
    System.out.println(hotelDoc);
}

```

### 4.3.删除文档

```java
/**
 * 测试方法，用于从酒店索引中删除指定文档。
 *
 * @throws IOException 如果发生输入输出错误，则抛出此异常
 */
@Test
void testDeleteDocument() throws IOException {
    // 1. 准备 DeleteRequest 对象，设置要删除的文档所在索引为 "hotel"，以及文档ID为 "36934"
    DeleteResponse response = client.delete(i -> i.index("hotel").id("36934"));
    // 2. 输出 DeleteResponse 对象中的结果状态
    System.out.println(response.result());
}

```

### 4.4.修改文档

```java
@Test
public void testUpdateDocument() throws IOException {
    // 1.根据id查询酒店数据
    Hotel hotel = hotelService.getById(61083L);
    // 2.转换为文档类型
    HotelDoc hotelDoc = new HotelDoc(hotel);
    hotelDoc.setPrice(1000);
    // 1.准备Request对象
    IndexResponse response = client.index(i -> i
            .index("hotel")
            .id("61083")
            .document(hotelDoc)
    );
    System.out.println("response.result() = " + response.result());

}
```

### 4.5.批量导入文档

```java
@Test
void testBulkRequest() throws IOException {
    // 从服务中查询并获取所有酒店数据
    List<Hotel> hotels = hotelService.list();

// 初始化一个批量操作列表，用于存储待执行的Elasticsearch批量操作
    List<BulkOperation> bulkOperations = new ArrayList<>();

// 对查询到的所有酒店进行遍历，并为每个酒店创建一个新的HotelDoc实例
    hotels.stream().forEach(hotel -> {
        HotelDoc hotelDoc = new HotelDoc(hotel);

// 创建一个批量操作，设置索引、文档内容（HotelDoc对象）以及文档ID
        BulkOperation operation = BulkOperation.of(b -> b.index(c -> c.document(hotelDoc).id(hotelDoc.getId().toString())));

// 将创建好的批量操作添加到批量操作列表中
        bulkOperations.add(operation);
    });

// 使用Elasticsearch客户端执行批量请求，索引名称为"hotel"，并将之前构建的所有批量操作应用于该请求
    BulkResponse response = client.bulk(b -> b.index("hotel").operations(bulkOperations));

// 打印出批量请求响应中的每个项目结果
    response.items().forEach(System.out::println);
}
```

## 五、查询文档

### 5.1.match_all查询

```java
@Test
void testMatchAll() throws IOException {
    // 使用客户端执行对"hotel"索引的搜索，其中查询语句为匹配所有文档（Match All Query）
    SearchResponse<HotelDoc> searchResponse = client.search(s -> s.index("hotel")
                             .query(a->a.matchAll(MatchAllQuery.of(b->b.queryName("")))), HotelDoc.class);
    
    // 处理并解析搜索响应结果
    handleResponse(searchResponse);
}
```

### 5.2.match查询

```java
@Test
void testMatch() throws IOException {
    // 创建一个针对“hotel”索引的搜索请求，其中包含一个match查询条件
    SearchRequest request = SearchRequest.of(b -> b
            .index("hotel")
            .query(q -> q.match(m -> m.field("all").query("如家"))) // 设置查询字段为"all"，查询关键词为"如家"
    );

// 执行搜索并获取响应结果，类型为HotelDoc的SearchResponse对象
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);

// 处理搜索响应结果
    handleResponse(searchResponse);
}
```

### 5.3.multiMatch多字段查询

```java
@Test
void testMultiMatch() throws IOException {
    // 创建一个多字段匹配查询的搜索请求，索引为"hotel"，查询字段包括"name"和"business"，查询关键词为"如家"
    SearchRequest request = SearchRequest.of(b -> b
            .index("hotel")
            .query(q -> q.multiMatch(a->a.fields("name","business").query("如家"))));

// 执行搜索并获取包含HotelDoc类型结果的响应
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);

// 处理搜索响应内容
    handleResponse(searchResponse);
}
```

### 5.4.精确查询

```java
@Test
void testTermMatchTest() throws IOException {
    // 创建一个带有term匹配查询的搜索请求
    SearchRequest request = SearchRequest.of(b -> b
            .index("hotel")
            .query(q -> q.term(t -> t.field("city").value("上海")))
    );
    
    // 执行搜索并获取响应
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);
    
    // 处理响应
    handleResponse(searchResponse);
}

```

### 5.5.范围查询

```java
/**
 * 范围查询
 */
@Test
void testRange() throws IOException {
    // 构造搜索请求
    SearchRequest request = SearchRequest.of(b -> b
            .index("hotel")
            .query(q -> q.range(r -> r.field("price").gte(JsonData.of(1000)).lte(JsonData.of(2000)))));
    // 执行搜索
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);
    // 处理搜索结果
    handleResponse(searchResponse);
}
```

### 5.6.布尔查询

```java
/**
 * 布尔查询
 */
@Test
void testBool() throws IOException {
    // 构造搜索请求
    SearchRequest request = SearchRequest.of(b -> b
            .index("hotel")
            .query(q -> q.bool(bq -> bq.must(m -> m.term(t -> t.field("city").value("上海"))).filter(f -> f.range(r -> r.field("price").lte(JsonData.of(250))))))
    );
    // 执行搜索
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);
    // 处理搜索结果
    handleResponse(searchResponse);
}
```

### 5.7.排序、分页

```java
/**
 * 进行分页查询的测试方法
 */
@Test
void testPageAndSort() throws IOException {
    // 定义当前页码和每页显示的记录数
    int page = 1, size = 50;
    
    // 构建搜索请求，指定索引为"hotel"，从((当前页码-1) * 每页大小)的位置开始获取数据
    // 并设置每页获取size条记录，同时按照price字段降序排序
    SearchRequest request = SearchRequest.of(b -> b
            .index("hotel")
            .from((page - 1) * size)
            .size(size).sort(s -> s.field(f -> f.field("price").order(SortOrder.Desc)))
    );
    
    // 使用Elasticsearch客户端执行搜索请求，返回HotelDoc类型的SearchResponse对象
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);
    
    // 处理并解析搜索响应结果
    handleResponse(searchResponse);
}
```

### 5.8.高亮

```java
/**
 * 高亮显示
 */
@Test
void testHighlight() throws IOException {
    // 构建搜索请求
    SearchRequest request = SearchRequest.of(b -> b
            .index("hotel")
            .query(q -> q.match(m -> m.field("all").query("如家")))
            .highlight(Highlight.of(o -> o.requireFieldMatch(false).fields("name", t -> t.preTags("<em style=\"color:red\">").postTags("</em>")))));

// 执行搜索请求
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);

// 处理搜索结果
    handleResponse(searchResponse);
}
```

### 5.9.地理位置（geo_distance）

- 查询半径范围内数据

```java
@Test
void testGeoDistance() throws IOException {
    // 创建SearchRequest对象
    SearchRequest request = SearchRequest.of(b -> b
            .index("hotel") // 设置索引名称为"hotel"
            .query(q -> q.geoDistance(g -> g.distance("100km").field("location").location(GeoLocation.of(a -> a.latlon(c -> c.lat(31.21).lon(121.5)))))) // 设置查询条件为距离"location"字段的值为100km的地理位置查询
    );
    // 执行查询
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);
    // 处理查询结果
    handleResponse(searchResponse);
}
```

- 查询半径数据后排序

```java
/**
 * 查询全部数据并根据地理位置排序
 */
@Test
void testGeoDistanceSort() throws IOException {
    // 创建SearchRequest对象
    SearchRequest request = SearchRequest.of(b -> b
            .index("hotel") // 设置索引名称为"hotel"
            .sort(s -> s.geoDistance(d -> d.field("location").location(l -> l.latlon(c -> c.lat(31.21).lon(121.5))).order(SortOrder.Asc).unit(DistanceUnit.Kilometers))) // 设置排序方式为根据地理位置排序，按照距离升序排列，单位为千米
    );
    // 执行搜索请求
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);
    // 处理搜索结果
    handleResponse(searchResponse);
}
```

### 5.10.算分函数查询

```java
@Test
public void testfunctionScore() throws IOException {
    // 创建SearchRequest对象
    SearchRequest request = SearchRequest.of(b -> b
            // 设置索引名称为"hotel"
            .index("hotel") 
            // 设置查询方式为算分函数查询，使用match查询匹配字段"all"中包含"外滩"的文档，设置一个过滤器，过滤出id为"434082"的文档，并设置权重为10.0，使用乘法方式计算得分
            .query(q -> q.functionScore(f -> f.query(w -> w.match(m -> m.field("all").query("外滩"))).functions(m -> m.filter(s -> s.term(t -> t.field("id").value("434082"))).weight(10.0)).boostMode(FunctionBoostMode.Multiply)))// 设置查询方式为算分函数查询，使用match查询匹配字段"all"中包含"外滩"的文档，设置一个过滤器，过滤出id为"434082"的文档，并设置权重为10.0，使用乘法方式计算得分 
    );
    // 执行搜索请求
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);
    // 处理搜索结果
    handleResponse(searchResponse);
}
```

### 5.11.公共返回值处理方法

```java
/**
 * 处理搜索响应
 * @param response 搜索响应
 */
private void handleResponse(SearchResponse<HotelDoc> response) {
    System.out.println("response = " + response);

// 4.解析响应
    HitsMetadata<HotelDoc> hitsMetadata = response.hits();

// 4.1.获取总条数
    long total = hitsMetadata.total().value();
    System.out.println("共搜索到" + total + "条数据");

// 4.2.获取结果集
    List<Hit<HotelDoc>> hits = hitsMetadata.hits();
    hits.forEach(hit -> {
        HotelDoc hotelDoc = hit.source();
        Map<String, List<String>> highlight = hit.highlight();

// 4.2.1.处理高亮显示
        if (highlight != null && highlight.containsKey("name")) {
            List<String> highlightedNames = highlight.get("name");
            System.out.println(highlightedNames.get(0));
            // 合并原name和高亮片段（这里假设只取第一个高亮片段）
            hotelDoc.setName(highlightedNames.get(0));
        }

// 4.2.2.处理排序结果
        List<FieldValue> sort = hit.sort();
        if (sort != null && sort.size() > 0) {
            // 4.2.1.获取排序字段
            FieldValue fieldValue = sort.get(1);
            // 4.2.2.获取排序值
            Object value = fieldValue.doubleValue();
            hotelDoc.setDistance(value);
        }
        System.out.println(hotelDoc);
    });
}
```

## 六、聚合搜索

### 6.1.bucket聚合

```java
/**
 * bucket聚合结果排序
 */
@Test
public void testBucketAggregation() throws IOException {
    SearchRequest request = SearchRequest.of(a -> a
            .index("hotel").query(b -> b.range(c -> c.field("price").lte(JsonData.of(200)))).aggregations("brand_agg", d -> d.terms(t -> t.field("brand").size(20).order(NamedValue.of("_count", SortOrder.Asc)))).size(0)
    );
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);
    handleAggResponse(searchResponse);
}
```

### 6.2.Metric聚合

```java
/**
 * Metric聚合语法测试
 */
@Test
public void testMetricAggregation() throws IOException {
    // 构建SearchRequest对象
    SearchRequest request = SearchRequest.of(a -> a
            .index("hotel").aggregations("brand_agg", d -> d.terms(e -> e.field("brand").size(20).order(NamedValue.of("score_agg.avg", SortOrder.Asc))).aggregations("score_agg", s -> s.stats(f -> f.field("score")))).size(0)
    );

// 执行搜索请求
    SearchResponse<HotelDoc> searchResponse = client.search(request, HotelDoc.class);

// 处理聚合响应
    handleAggResponse(searchResponse);
}
```

### 6.3.处理聚合响应结果

```java
/**
 * 处理聚合响应
 *
 * @param searchResponse 搜索响应
 */
private void handleAggResponse(SearchResponse<HotelDoc> searchResponse) {
    // 打印搜索响应
    // System.out.println(searchResponse);
    // 获取聚合结果
    Map<String, Aggregate> aggregations = searchResponse.aggregations();
    // 打印聚合结果
    // System.out.println(aggregations);
    // 获取品牌聚合结果
    Aggregate brandAgg = aggregations.get("brand_agg");
    // 获取品牌聚合结果的字符串聚合结果
    StringTermsAggregate stermsAggregate = brandAgg.sterms();
    // 获取品牌聚合结果的桶
    Buckets<StringTermsBucket> buckets = stermsAggregate.buckets();
    // 将桶转换为列表
    List<StringTermsBucket> bucketList = buckets.array();
    // 遍历桶列表
    bucketList.forEach(bucket -> {
        // 获取桶的key
        String key = bucket.key().stringValue();
        // 获取桶的docCount
        long docCount = bucket.docCount();
        // 获取桶的聚合结果
        Map<String, Aggregate> scoreAgg = bucket.aggregations();
        if (scoreAgg.size()>0) {
            // 获取桶的score聚合结果
            Aggregate aggregate = scoreAgg.get("score_agg");
            // 获取score聚合结果的统计聚合结果
            StatsAggregate statsAggregate = aggregate.stats();
            System.out.println("key:" + key + ", docCount:" + docCount + ", score_agg:" + statsAggregate);
         }
        // 打印全部参数
        System.out.println("key:" + key + ", docCount:" + docCount);
    });
}
```

## 七、自动补全

### 7.1.拼音分词器

[下载地址](https://github.com/medcl/elasticsearch-analysis-pinyin)

解压后重命名放入以下目录

### 7.2.创建索引

- 在HotelConsts.java中添加以下代码

```java
public static final String INDEX_TEMPLATE = """
            {
              "settings": {
                "analysis": {
                  "analyzer": {
                    "text_anlyzer": {
                      "tokenizer": "ik_max_word",
                      "filter": "py"
                    },
                    "completion_analyzer": {
                      "tokenizer": "keyword",
                      "filter": "py"
                    }
                  },
                  "filter": {
                    "py": {
                      "type": "pinyin",
                      "keep_full_pinyin": false,
                      "keep_joined_full_pinyin": true,
                      "keep_original": true,
                      "limit_first_letter_length": 16,
                      "remove_duplicated_term": true,
                      "none_chinese_pinyin_tokenize": false
                    }
                  }
                }
              },
              "mappings": {
                "properties": {
                  "id":{
                    "type": "keyword"
                  },
                  "name":{
                    "type": "text",
                    "analyzer": "text_anlyzer",
                    "search_analyzer": "ik_smart",
                    "copy_to": "all"
                  },
                  "address":{
                    "type": "keyword",
                    "index": false
                  },
                  "price":{
                    "type": "integer"
                  },
                  "score":{
                    "type": "integer"
                  },
                  "brand":{
                    "type": "keyword",
                    "copy_to": "all"
                  },
                  "city":{
                    "type": "keyword"
                  },
                  "starName":{
                    "type": "keyword"
                  },
                  "business":{
                    "type": "keyword",
                    "copy_to": "all"
                  },
                  "location":{
                    "type": "geo_point"
                  },
                  "pic":{
                    "type": "keyword",
                    "index": false
                  },
                  "all":{
                    "type": "text",
                    "analyzer": "text_anlyzer",
                    "search_analyzer": "ik_smart"
                  },
                  "suggestion":{
                    "type": "completion",
                    "analyzer": "completion_analyzer"
                  }
                }
              }
            }
            
            """;
```

- 编写创建索引代码

```java
/**
 * 创建索引测试方法，该方法读取HotelIndexConsts.INDEX_TEMPLATE中的模板内容，
 * 并使用其创建一个名为"hotel2"的索引请求。
 *
 * @throws Exception 如果在创建索引过程中出现异常，则抛出异常
 */
@Test
public void createIndex() throws Exception {
    // 创建一个从字符串读取器，读取预定义的索引模板内容
    Reader reader = new StringReader(HotelIndexConsts.INDEX_TEMPLATE);

// 使用读取到的模板内容构建一个CreateIndexRequest对象，指定索引名称为"hotel2"
    CreateIndexRequest request = CreateIndexRequest.of(a -> a.index("hotel2").withJson(reader));

// 调用Elasticsearch客户端的indices().create()方法发送创建索引请求
    CreateIndexResponse response = client.indices().create(request);

// 输出响应结果，检查索引是否成功创建（acknowledged字段表示操作是否被集群中所有相关节点确认执行）
    System.out.println(response.acknowledged());
}

```

- 执行批量导入数据到es

```java
//批量导入数据到es
@Test
void testBulkRequest() throws IOException {
    // 批量查询酒店数据
    List<Hotel> hotels = hotelService.list();
    List<BulkOperation> bulkOperations = new ArrayList<>();
    hotels.stream().forEach(hotel -> {
        HotelDoc hotelDoc = new HotelDoc(hotel);
        bulkOperations.add(BulkOperation.of(b -> b.index(c -> c.document(hotelDoc).id(hotelDoc.getId().toString()))));
    });
    BulkResponse response = client.bulk(b -> b.index("hotel2").operations(bulkOperations));
    response.items().forEach(System.out::println);
}
```

### 7.3.自动补全

```java
/**
 * 自动补全测试
 */
@Test
void testSuggest() throws IOException {
    // 创建搜索请求
    SearchRequest searchRequest = SearchRequest.of(a -> 
        a.index("hotel2").suggest(b -> b.suggesters("my_suggest", c -> c.text("h").completion(d -> d.field("suggestion").skipDuplicates(true).size(10))))
    );
    
    // 执行搜索请求
    SearchResponse<HotelDoc> searchResponse = client.search(searchRequest, HotelDoc.class);
    
    // 处理搜索响应
    handleResponse(searchResponse);
}
```

### 7.4.处理响应结果

```java
/**
 * 处理响应结果
 *
 * @param searchResponse 搜索响应结果
 */
private void handleResponse(SearchResponse<HotelDoc> searchResponse) {
    // 获取建议结果
    Map<String, List<Suggestion<HotelDoc>>> suggestions = searchResponse.suggest();
    // 获取指定建议结果
    Suggestion<HotelDoc> suggestion = suggestions.get("my_suggest").getFirst();
    // 获取建议结果的选项列表
    List<CompletionSuggestOption<HotelDoc>> options = suggestion.completion().options();
    // 遍历选项列表并打印选项文本
    options.forEach(option -> {
        System.out.println(option.text());
    });
}
```

## 八、实践项目地址

[码云](https://gitee.com/satan1996/elasticsearch-learn.git)

[本地knife4j文档地址](http://localhost:8080/doc.html)

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