ES学习(一)

原创已于 2023-04-25 15:04:55 修改 · 337 阅读

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#elasticsearch #学习 #大数据

于 2023-03-06 00:41:38 首次发布

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1、基本语法已分享至百度网盘，此处不再描述了，可以下载后，使用postman工具导入此json文件进行学习基本语法

链接：https://pan.baidu.com/s/1lY7dB9Q9lewBF46z9ss5fw
提取码：pvq6

2、springboot使用api对接es,首先确定自己的springboot版本，找到对应的es版本去使用

3、确定好自己的版本后加入 es依赖包，比如我使用的boot版本为2.2.7版本，对应的es版本就应该是6.8.12，es客户端依赖的jar包最好也要保持同步，我的pom文件依赖如下

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.wxg</groupId>
    <artifactId>es</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>es</name>
    <description>Demo project for Spring Boot</description>

    <dependencies>
        <!-- elasticsearch 的jar包 -->
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>6.8.12</version>
        </dependency>
        <!-- elasticsearch 的客户端 -->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>6.8.12</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>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

4、在springboot写一个main方法，测试是否可以正常使用，本次示例直接创建一个新的索引

package com.wxg.es.test;

import org.apache.http.HttpHost;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.indices.CreateIndexRequest;
import org.elasticsearch.client.indices.CreateIndexResponse;

import java.io.IOException;

public class createIndex {
    public static void main(String[] args) throws IOException {
        //创建es客户端对象
        RestHighLevelClient restHighLevelClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );
        //创建索引请求
        CreateIndexRequest user = new CreateIndexRequest("user");
        //创建索引，得到Response返回
        CreateIndexResponse createIndexResponse = restHighLevelClient.indices().create(user, RequestOptions.DEFAULT);
        //获取执行结果 true为成功，false为失败
        boolean acknowledged = createIndexResponse.isAcknowledged();
        System.out.println("索引创建："+acknowledged);        
        //关闭客户端对象
        restHighLevelClient.close();
    }
}

5、在postman中找到“查询所有索引”进行查询，可以看到已经新建成功了

6、以上是新建部分的代码，删除(DeleteIndexRequest)、查询(GetIndexRequest),基本都是同理

7、创建索引后，我们来向索引文档中添加数据，新建一个IndexInsert.class文件

package com.wxg.es.test;

import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.http.HttpHost;
import org.elasticsearch.action.DocWriteResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;

import java.io.IOException;

public class IndexInsert {
    public static void main(String[] args) throws IOException {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );

        // 新增文档 - 请求对象
        IndexRequest request = new IndexRequest();
        // 设置索引及唯一性标识
        request.type("String");
        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);
        System.out.println("_index:" + response.getIndex());

        client.close();
    }
}

8、值得注意的是es7.x后默认都是_doc类型的type，但是我们现在用得是6.8，所以，我们在写入文档时候，必须指定一下type类型，不然会报以下错误