Elasticsearch SpringBoot 整合 ES

一.ES 的Java API两种方式

  Elasticsearch 的API 分为 REST Client API（http请求形式）以及 transportClient

API两种。相比来说transportClient API效率更高，transportClient

是通过Elasticsearch内部RPC的形式进行请求的，连接可以是一个长连接，相当于是把客户端的请求当成

  Elasticsearch 集群的一个节点，当然 REST Client API 也支持http

keepAlive形式的长连接，只是非内部RPC形式。但是从Elasticsearch 7 后就会移除transportClient

。主要原因是transportClient 难以向下兼容版本。

1.1 9300[TCP]

  利用9300端口的是spring-data-elasticsearch:transport-api.jar,但是这种方式因为对应的SpringBoot版本不一致，造成对应的transport-api.jar也不同，不能适配es的版本，而且ElasticSearch7.x中已经不推荐使用了，ElasticSearch 8之后更是废弃了，所以我们不做过多的介绍

1.2 9200[HTTP]

  基于9200端口的方式也有多种

• JsetClient:非官方，更新缓慢
• RestTemplate:模拟发送Http请求，ES很多的操作需要我们自己来封装，效率低
• HttpClient：和上面的情况一样
• ElasticSearch-Rest-Client:官方的RestClient，封装了ES的操作，API层次分明，易于上手。
• JavaAPIClient 7.15版本后推荐

二.ElasticSearch-Rest-Client整合

1、导入依赖

https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.4/java-rest-high-getting-started-maven.html

       <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.4.2</version>
        </dependency>

SpringBoot 自己带了一个版本，需要我们替换掉

    <properties>
        <java.version>1.8</java.version>
        <elasticsearch.version>7.4.2</elasticsearch.version>
    </properties>

2、完整pom.xml

<?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>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.atguigu.gulimall</groupId>
    <artifactId>zeal-search</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>gulimall-search</name>
    <description>ElasticSearch-检索服务</description>
    <properties>
        <java.version>1.8</java.version>
        <elasticsearch.version>7.4.2</elasticsearch.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>com.atguigu.gulimall</groupId>
            <artifactId>gulimall-common</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.4.2</version>
        </dependency>
        <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>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

3、Config配置

https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.4/java-rest-high-getting-started-initialization.html

package com.atguigu.gulimall.search.config;

import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;


@Configuration
public class SearchConfig {

    @Bean
    public RestHighLevelClient esRestClient(){
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("192.168.56.10", 9201, "http")));

        return client;
    }

}

4、启动类排除数据源

package com.mangoubiubiu.search;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

import javax.sql.DataSource;

@EnableDiscoveryClient
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
public class ZealSearchApplication {

    public static void main(String[] args) {
        SpringApplication.run(ZealSearchApplication.class, args);
    }

}

5、测试类

package com.mangoubiubiu.search;

import org.elasticsearch.client.RestHighLevelClient;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;


@RunWith(SpringRunner.class)
@SpringBootTest
public class ZealSearchApplicationTests {

    @Autowired
    private RestHighLevelClient restHighLevelClient;

    @Test
   public void contextLoads() {
        System.out.println(restHighLevelClient);
    }

}