Elasticsearch-RestClient基础

零、本文纲要

• 一、认识RestClient
• 二、使用RestClient
  1、基础准备
  2、RestClient操作索引库
  ...
  ③ 编写创建索引库方法
  ④ 编写删除索引库方法
  ⑤ 编写判断是否存在索引库方法
  3、RestClient操作文档
  ① 添加文档数据方法
  ② 获取文档数据方法
  ③ 更新文档数据方法
  ④ 删除文档数方法
  ⑤ 批量操作方法

tips：Ctrl + F快速定位所需内容阅读吧。

一、认识RestClient

Java REST Client (deprecated) | Elastic
Overview (rest-high-level 7.12.1 API) (elastic.co)

ES官方提供了各种不同语言的客户端，用来操作ES。这些客户端的本质就是组装DSL语句，通过http请求发送给ES。

RestClient是提供给Java的客户端。

二、使用RestClient

1、基础准备

• ① 创建表格

创建数据表tb_hotel，如下：

DROP TABLE IF EXISTS `tb_hotel`;
CREATE TABLE `tb_hotel`  (
  `id` bigint(20) NOT NULL COMMENT '酒店id',
  `name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '酒店名称',
  `address` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '酒店地址',
  `price` int(10) NOT NULL COMMENT '酒店价格',
  `score` int(2) NOT NULL COMMENT '酒店评分',
  `brand` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '酒店品牌',
  `city` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '所在城市',
  `star_name` varchar(16) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '酒店星级，1星到5星，1钻到5钻',
  `business` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '商圈',
  `latitude` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '纬度',
  `longitude` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '经度',
  `pic` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '酒店图片',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Compact;

插入数据，如下：

INSERT INTO `tb_hotel` VALUES (36934, '7天连锁酒店(上海宝山路地铁站店)', '静安交通路40号', 336, 37, '7天酒店', '上海', '二钻', '四川北路商业区', '31.251433', '121.47522', 'https://m.tuniucdn.com/fb2/t1/G1/M00/3E/40/Cii9EVkyLrKIXo1vAAHgrxo_pUcAALcKQLD688AAeDH564_w200_h200_c1_t0.jpg');
INSERT INTO `tb_hotel` VALUES (38609, '速8酒店(上海赤峰路店)', '广灵二路126号', 249, 35, '速8', '上海', '二钻', '四川北路商业区', '31.282444', '121.479385', 'https://m.tuniucdn.com/fb2/t1/G2/M00/DF/96/Cii-TFkx0ImIQZeiAAITil0LM7cAALCYwKXHQ4AAhOi377_w200_h200_c1_t0.jpg');
INSERT INTO `tb_hotel` VALUES (38665, '速8酒店上海中山北路兰田路店', '兰田路38号', 226, 35, '速8', '上海', '二钻', '长风公园地区', '31.244288', '121.422419', 'https://m.tuniucdn.com/fb2/t1/G2/M00/EF/86/Cii-Tlk2mV2IMZ-_AAEucgG3dx4AALaawEjiycAAS6K083_w200_h200_c1_t0.jpg');
INSERT INTO `tb_hotel` VALUES (38812, '7天连锁酒店(上海漕溪路地铁站店)', '徐汇龙华西路315弄58号', 298, 37, '7天酒店', '上海', '二钻', '八万人体育场地区', '31.174377', '121.442875', 'https://m.tuniucdn.com/fb2/t1/G2/M00/E0/0E/Cii-TlkyIr2IEWNoAAHQYv7i5CkAALD-QP2iJwAAdB6245_w200_h200_c1_t0.jpg');
INSERT INTO `tb_hotel` VALUES (39106, '7天连锁酒店（上海莘庄地铁站店）', '闵行莘庄镇七莘路299号', 348, 41, '7天酒店', '上海', '二钻', '莘庄工业区', '31.113812', '121.375869', 'https://m.tuniucdn.com/fb2/t1/G2/M00/D8/11/Cii-T1ku2zGIGR7uAAF1NYY9clwAAKxZAHO8HgAAXVN368_w200_h200_c1_t0.jpg');
INSERT INTO `tb_hotel` VALUES (39141, '7天连锁酒店(上海五角场复旦同济大学店)', '杨浦国权路315号', 349, 38, '7天酒店', '上海', '二钻', '江湾、五角场商业区', '31.290057', '121.508804', 'https://m.tuniucdn.com/fb2/t1/G2/M00/C7/E3/Cii-T1knFXCIJzNYAAFB8-uFNAEAAKYkQPcw1IAAUIL012_w200_h200_c1_t0.jpg');
INSERT INTO `tb_hotel` VALUES (416121, '如家酒店(北京西客站北广场店)', '莲花池东路120-2号6层', 275, 43, '如家', '北京', '二钻', '北京西站/丽泽商务区', '39.896449', '116.317382', 'https://m.tuniucdn.com/fb3/s1/2n9c/42DTRnKbiYoiGFVzrV9ZJUxNbvRo_w200_h200_c1_t0.jpg');

• ② 引入依赖

elasticsearch相关依赖，如下：

        <!--elasticsearch-->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.12.1</version>
        </dependency>

因为SpringBoot默认的ES版本是7.6.2，所以我们需要覆盖默认的ES版本：

    <properties>
        <!--指定我们所需的版本，覆盖springboot默认配置-->
        <elasticsearch.version>7.12.1</elasticsearch.version>
    </properties>

其他依赖，如下：

        <!--web-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--mybatis_plus-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.4.2</version>
        </dependency>
        <!--mysql_connector-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!--test-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <!--FastJson-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.71</version>
        </dependency>
        <!--commons-lang3:工具包-->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>

• ③ application.yml

Ⅰ 配置服务端口；
Ⅱ 配置数据源；
Ⅲ 配置日志；
Ⅳ 配置mybatis-plus。

server:
  port: 8089
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test?useSSL=false
    username: root
    password: root
    driver-class-name: com.mysql.jdbc.Driver
logging:
  level:
    cn.test: debug
  pattern:
    dateformat: MM-dd HH:mm:ss:SSS
mybatis-plus:
  configuration:
    map-underscore-to-camel-case: true
  type-aliases-package: cn.test.hotel.pojo

• ④ 编写实体类

Hotel类

@Data
@TableName("tb_hotel")
public class Hotel {
    @TableId(type = IdType.INPUT)
    private Long id;
    private String name;
    private String address;
    private Integer price;
    private Integer score;
    private String brand;
    private String city;
    private String starName;
    private String business;
    private String longitude;
    private String latitude;
    private String pic;
}

HotelDoc类

@Data
@NoArgsConstructor
public class HotelDoc {
    private Long id;
    private String name;
    private String address;
    private Integer price;
    private Integer score;
    private String brand;
    private String city;
    private String starName;
    private String business;
    private String location;
    private String pic;

    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();
    }
}

geo_point类型属性映射的形式有多种，官方文档见此：Geopoint field type
，常见的形式如下图。此处我们采用第2种形式，做属性映射"location": "41.12,-71.34"，所以在类型转换的时候手动拼接了属性值this.location = hotel.getLatitude() + ", " + hotel.getLongitude();。

location字段geopoint的映射.png

• ⑤ 编写mapper接口及service接口&实现类

public interface HotelMapper extends BaseMapper<Hotel> {
}

public interface IHotelService extends IService<Hotel> {
}

@Service
public class HotelService extends ServiceImpl<HotelMapper, Hotel> implements IHotelService {
}

2、RestClient操作索引库

• ① 创建索引库

Ⅰ 编写创建索引库语句：这个步骤可以在自己Dev Tools控制台内完成，然后将字段复制到IDEA。

public class HotelConstant {

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

}

• ② 编写测试类

@BeforeEach内完成client对象的初始化配置，@AfterEach内完成操作后的资源释放。

public class HotelIndexTest {

    private RestHighLevelClient client;

    @BeforeEach
    void setUp(){
        this.client = new RestHighLevelClient(RestClient.builder(
                HttpHost.create("http://192.168.253.128:9200")
        ));
    }

    ... ...

    @AfterEach
    void tearDown(){
        try {
            this.client.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

• ③ 编写创建索引库方法

    @Test
    void createHotelIndex(){
        // 1. 创建Request对象
        CreateIndexRequest request = new CreateIndexRequest("hotel");
        // 2. 准备请求参数DSL语句
        request.source(HotelConstant.MAPPING_TEMPLATE, XContentType.JSON);
        // 3. 发送请求
        try {
            client.indices().create(request, RequestOptions.DEFAULT);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

创建索引库.png

• ④ 编写删除索引库方法

    @Test
    void deleteHotelIndex(){
        // 1. 创建Request对象
        DeleteIndexRequest request = new DeleteIndexRequest("hotel");
        // 2. 发送请求
        try {
            client.indices().delete(request, RequestOptions.DEFAULT);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

• ⑤ 编写判断是否存在索引库方法

    @Test
    void existsHotelIndex(){
        // 1. 创建Request对象
        GetIndexRequest request = new GetIndexRequest("hotel");
        // 2. 发送请求
        try {
            boolean exists = client.indices().exists(request, RequestOptions.DEFAULT);
            System.err.println(exists ? "hotel index exists!" : "hotel index not exist!");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

不难看出对索引库的操作有一定的相似性：
Ⅰ XXXIndexRequest：Create、Delete、Get的请求request对象；
Ⅱ client.indices().XXX()：create、delete、get方法。

3、RestClient操作文档

添加@SpringBootTest注解，注入hotelService：

    @Resource
    private IHotelService hotelService;

• ① 添加文档数据方法

    @Test
    void addDocument(){
        // 1. 查询数据库
        Hotel hotel = hotelService.getById(36934L);
        // 2. 封装成DOC对象
        HotelDoc hotelDoc = new HotelDoc(hotel);
        // 3. 获取request对象
        IndexRequest request = new IndexRequest("hotel").id(hotel.getId().toString());
        // 4. 将数据放入request
        request.source(JSON.toJSONString(hotelDoc), XContentType.JSON);
        // 5. 存储数据
        try {
            client.index(request, RequestOptions.DEFAULT);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

• ② 获取文档数据方法

    @Test
    void getDocumentById(){
        // 1. 创建request对象
        GetRequest request = new GetRequest("hotel", "36934");
        try {
            // 2. 发送请求，得到结果
            GetResponse response = client.get(request, RequestOptions.DEFAULT);
            // 3. 解析结果
            String json = response.getSourceAsString();

            System.out.println(json);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

• ③ 更新文档数据方法

    @Test
    void updateDocumentById(){
        // 1. 创建request对象
        UpdateRequest request = new UpdateRequest("hotel", "36934");
        // 2. 设置更新字段
        request.doc(
                "price", "346",
                "starName", "三钻"
        );
        // 3. 更新文档
        try {
            client.update(request, RequestOptions.DEFAULT);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

• ④ 删除文档数方法

    @Test
    void deleteDocumentById(){
        // 1. 创建request对象
        DeleteRequest request = new DeleteRequest("hotel", "36934");
        // 2. 删除文档
        try {
            client.delete(request, RequestOptions.DEFAULT);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

• ⑤ 批量操作方法

    @Test
    void bulkRequest(){
        // 1. 获取请求对象
        BulkRequest request = new BulkRequest();
        // 2. 准备参数，添加多个新增的Request
        // 2.1 批量获取数据库的数据
        List<Hotel> hotelList = hotelService.list();
        for (int i = 0; i < hotelList.size(); i++) {
            // 2.2 获取hotel对象
            Hotel hotel = hotelList.get(i);
            // 2.3 转换成hotelDoc对象
            HotelDoc hotelDoc = new HotelDoc(hotel);
            /*// 2.4 获取request对象
            IndexRequest indexRequest = new IndexRequest("hotel").id(hotel.getId().toString());
            // 2.5 将数据放入request
            indexRequest.source(JSON.toJSONString(hotelDoc), XContentType.JSON);
            // 2.6 将indexRequest对象加入request
            request.add(indexRequest);*/
            request.add(new IndexRequest("hotel")
                    .id(hotelDoc.getId().toString())
                    .source(JSON.toJSONString(hotelDoc), XContentType.JSON));
        }
        // 3. 批量添加
        try {
            client.bulk(request, RequestOptions.DEFAULT);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

不难看出对索引文档的操作也具有一定的相似性：
Ⅰ XXXRequest：Index、Get、Update、Delete、Bulk的请求request对象；
Ⅱ client.XXX()方法：index、get、update、delete、bulk方法。

三、结尾

以上即为RestClient基础的全部内容，感谢阅读。