RestClient操作索引库_resclient

作者：小小林熬夜学编程 | 2024-06-01 19:54:28

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resclient

RestClient是es官方提供的一套用于通过代码操作es的api，es官方提供了不同语言的客户端，这些客户端本质上就是组装的DSL语句，通过http请求发送给es

步骤一：数据库中导入表和数据

步骤二：分析数据结构

在kibana中设置

步骤三：初始化JavaRestClient

使用es需要引入对应的依赖，注意依赖版本要和es版本一致

<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
</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>
<java.version>1.8</java.version>
<elasticsearch.version>7.12.1</elasticsearch.version>
</properties>

创建一个测试类，先初始化RestHighLevelClient，连接到es，代码如下


import java.io.IOException;
 
public class HotelIndexTest {
    private RestHighLevelClient client;
 
    //声明对象，并做对象初始化连接到es，提高代码复用性
    @BeforeEach
    void setUp(){
        this.client = new RestHighLevelClient(RestClient.builder(
           HttpHost.create("http://192.168.61.130:9200")
        ));
    }
 
    @AfterEach
    void tearDown() throws IOException {
        this.client.close();
    }
}

步骤4：创建索引库

成功后创建一个新的索引库，这里的DSL语句需要我们手动编写或者自己引入，我先新建一个类，写好DSL语句,在Dev Tools写一个，然后复制到代码里去，如下


public class HotelConstants {
    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" +
            "}";
}

然后写新增索引库的方法，并将刚才的DSL语句引入到下面代码中，如下


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

步骤五：删除索引库、判断索引库是否存在


    //删除索引库
    @Test  
    void testDeleteHotelIndex() throws IOException {
        //创建删除对象
        DeleteIndexRequest request = new DeleteIndexRequest("hotel");
        //删除请求
        client.indices().delete(request,RequestOptions.DEFAULT);
    }


    //判断索引是否存在
    @Test  
    void testExistsHotelIndex() throws IOException {
        //查看索引库
        GetIndexRequest getIndexRequest = new GetIndexRequest("hotel");
        //判断索引库是否存在
        boolean exists = client.indices().exists(getIndexRequest, RequestOptions.DEFAULT);
 
        System.out.println(exists ? "索引库存在":"索引库不存在" );//打印true或者false判断索引库是否存在
 
    }

文档的基本操作

新增文档：通常情况新增的数据都是从数据库导入的，所以需要先连接数据库并查到数据，并且根据数据库的字段创建对应的索引库，然后才是导入数据，先创建pojo对象，这里取名Hotel，


@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; //经度
    private String latitude; //纬度
    private String pic;
}

这个数据库表有一个地理位置，用经纬度表示，是两个字段，而在es中经纬度是将这两个字段拼接起来的一个字段，格式不同所以要做转换，所以要再写一个pojo对象这里叫做HotelDoc


@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();//这里将数据库的两个字段拼为一个
        this.pic = hotel.getPic();
    }
}

新建一个测试类，通过mybatisplus查询数据库内的内容上传到es中


@SpringBootTest
public class HotelDocumentTest {
 
    @Autowired
    private IHotelService hotelService;
 
    private RestHighLevelClient client;
 
    @Test
    void testAddDocument() throws IOException {
        //根据id查询数据
        Hotel hotel = hotelService.getById(61083L);
        //因为没有经纬度，设置了一个新实体类混合经纬度
        HotelDoc hotelDoc = new HotelDoc(hotel);
        //1.准备Request对象
        IndexRequest request = new IndexRequest("hotel").id(hotelDoc.getId().toString());
        //2.准备Json文档
        request.source(JSON.toJSON(hotelDoc),XContentType.JSON);
        //3.发送请求
        client.index(request,RequestOptions.DEFAULT);
    }
 
 
    //声明对象，并做对象初始化连接到es，提高代码复用性
    @BeforeEach
    void setUp(){
        this.client = new RestHighLevelClient(RestClient.builder(
           HttpHost.create("http://192.168.61.130:9200")
        ));
    }
 
    @AfterEach
    void tearDown() throws IOException {
        this.client.close();
    }
}

查询操作


    @Test
    void testGetDocumentById() throws IOException {
        //准备request
        GetRequest request = new GetRequest("hotel", "61083");
        //发送请求得到响应
        GetResponse response = client.get(request, RequestOptions.DEFAULT);
        //解析响应结果
        String json = response.getSourceAsString();
        //反序列化json
        HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);
        System.err.println(hotelDoc);
    }

删除操作


    @Test
    void deleteDocumentest() throws IOException {
        //1、准备request
        DeleteRequest request= new DeleteRequest("hotel", "61083");
        //2、发送请求
        client.delete(request,RequestOptions.DEFAULT);
    }

修改操作

方式一：全量更新。再次写入id一样的文档，就会删除旧文档，添加新文档

方式二：局部更新。只更新部分字段，我们演示方式二


    @Test
    void testUpdateDocumentById() throws IOException {
        //1,新建request对象
        UpdateRequest request = new UpdateRequest("hotel", "61083");
        //2.准备参数
        request.doc(
                "price","1000",
                "starName","四钻"
        );
        //3,发送请求
        client.update(request,RequestOptions.DEFAULT);
    }

批量数据导入操作


     void BulkRequest() throws IOException {
        //1、创建request
        BulkRequest bulkRequest = new BulkRequest();
        //批量查询数据库数据
        List<Hotel> list = hotelService.list();
        //遍历是因为数据库数据较多
        for (Hotel hotel : list) {
            //转换为文档类型
            HotelDoc hotelDoc = new HotelDoc(hotel);
            //2、准备参数，添加多个新增的Request
            bulkRequest.add(new IndexRequest("hotel").
                    id(hotelDoc.getId().toString()).
                    source(JSON.toJSONString(hotelDoc),XContentType.JSON));
        }//这里就是一个链式编程，直接调用了对象的方法，而不像之前是分步写
       
 
        //不理解遍历的，也可以 自己一条条数据的添加进去，如下,就是很麻烦
/*bulkRequest.add(new IndexRequest("hotel").
                    id("1").
                    source(JSON.toJSONString(hotelDoc),XContentType.JSON));
bulkRequest.add(new IndexRequest("hotel").
                    id("2").
                    source(JSON.toJSONString(hotelDoc),XContentType.JSON));
bulkRequest.add(new IndexRequest("hotel").
                    id("3").
                    source(JSON.toJSONString(hotelDoc),XContentType.JSON));*/
        
 
 //3、发送请求
        client.bulk(bulkRequest,RequestOptions.DEFAULT);
    }

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