elasticsearch 客户端实战演示之java语言

超、凢脫俗 2023-10-03 22:52 14阅读 0赞

此篇客户端实战基于java语言，分享的客户端有RestHighLevelClient、Spring Data Elastcsearch这两种：

一、java 客户端配置使用

1、项目核心依赖配置：

<dependency>
                <groupId>org.elasticsearch.client</groupId>
                <artifactId>elasticsearch-rest-high-level-client</artifactId>
                <version>7.9.3</version>
            </dependency>
           
           <dependency>
                <groupId>org.elasticsearch</groupId>
                <artifactId>elasticsearch</artifactId>
                <version>7.9.3</version>
            </dependency>

2、application.properties配置

elasticsearch.rest.hosts=127.0.0.1:9200
    elasticsearch.rest.username=elastic
    elasticsearch.rest.password=password

协调节点的服务地址、用户名和密码。

3、不带验证的客户端

package com.roy.rocketmq.scenic;
    
    import org.apache.http.HttpHost;
    import org.elasticsearch.client.RestClient;
    import org.elasticsearch.client.RestHighLevelClient;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.context.annotation.Bean;
    import org.springframework.stereotype.Component;
    
    import java.util.Arrays;
    import java.util.Objects;
    
    /**
     * @author wanghuainan
     * @date 2023/1/1 18:42
     */
    @Component
    public class EsClient {
    
        @Value("${elasticsearch.rest.hosts}")
        private String hosts;
    
         @Bean
        public RestHighLevelClient initSimpleClient(){
            //根据配置文件配置HttpHost数组
            HttpHost[] httpHosts = Arrays.stream(hosts.split(",")).map(
                    host -> {
                        //分隔es服务器IP和端口
                        String[] hostParts = host.split(":");
                        String hostName = hostParts[0];
                        int port = Integer.parseInt(hostParts[1]);
                        return new HttpHost(hostName, port, HttpHost.DEFAULT_SCHEME_NAME);
                    }).filter(Objects::nonNull).toArray(HttpHost[]::new);
            return new RestHighLevelClient(RestClient.builder(httpHosts));//构建客户端
        }
    }

4、带验证用户的客户端

import org.apache.http.HttpHost;
    import org.apache.http.auth.AuthScope;
    import org.apache.http.auth.UsernamePasswordCredentials;
    import org.apache.http.client.CredentialsProvider;
    import org.apache.http.impl.client.BasicCredentialsProvider;
    import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
    import org.elasticsearch.client.RestClient;
    import org.elasticsearch.client.RestClientBuilder;
    import org.elasticsearch.client.RestHighLevelClient;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.context.annotation.Bean;
    import org.springframework.stereotype.Component;
    
    import java.util.Arrays;
    import java.util.Objects;
    /**
     * @author wanghuainan
     * @date 2023/1/1 18:42
     */
    @Component
    public class EsClient {
        @Value("${elasticsearch.rest.hosts}")//读取es主机+端口配置
        private String hosts;
        @Value("${elasticsearch.rest.username}")//读取es用户名
        private String esUser;
        @Value("${elasticsearch.rest.password}")//读取es密码
        private String esPassword;
    
     
        @Bean
        public RestHighLevelClient initClient1() {
            //根据配置文件配置HttpHost数组
            HttpHost[] httpHosts = Arrays.stream(hosts.split(",")).map(
                    host -> {
                        //分隔es服务器IP和端口
                        String[] hostParts = host.split(":");
                        String hostName = hostParts[0];
                        int port = Integer.parseInt(hostParts[1]);
                        return new HttpHost(hostName, port, HttpHost.DEFAULT_SCHEME_NAME);
                    }).filter(Objects::nonNull).toArray(HttpHost[]::new);
            //生成凭证
            final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
            credentialsProvider.setCredentials(AuthScope.ANY,
                    new UsernamePasswordCredentials(esUser, esPassword));//明文凭证
            //返回带验证的客户端
            return new RestHighLevelClient(
                    RestClient.builder(
                            httpHosts)
                            .setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
                                public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
                                    httpClientBuilder.disableAuthCaching();
                                    return httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
                                }
                            }));
        }
    }

5、创建景区实体类

import lombok.Data;
    
    @Data
    public class Scenic {
        String id;//对应于文档_id
        String index;//对应于索引名称
        Float score;//对应于文档得分
    
        String title; //对应于索引中的title
        String city; //对应于索引中的city
        Double price; //对应于索引中的price
    }

6、核心业务查询

public List<Scenic> getScenicFromTitle(String keyword) {
            SearchRequest searchRequest = new SearchRequest("scenic");//客户端请求
            SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
            searchSourceBuilder.query(QueryBuilders.matchQuery("title", keyword));//构建query
            searchRequest.source(searchSourceBuilder);
            List<Scenic> resultList = new ArrayList<Scenic>();
            try {
                SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
                RestStatus status = searchResponse.status();
                if (status != RestStatus.OK) {
                    return null;
                }
                SearchHits searchHits = searchResponse.getHits();
                for (SearchHit searchHit : searchHits) {
                    Scenic scenic = new Scenic();
                    scenic.setId(searchHit.getId());//文档_id
                    scenic.setIndex(searchHit.getIndex());//索引名称
                    scenic.setScore(searchHit.getScore());//文档得分
    
                    Map<String, Object> dataMap = searchHit.getSourceAsMap();//转换为Map
                    scenic.setTitle((String) dataMap.get("title"));//设置标题
                    scenic.setCity((String) dataMap.get("city"));//设置城市
                    scenic.setPrice((Double) dataMap.get("price"));//设置价格
                    resultList.add(scenic);
                }
                return resultList;
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }

7、控制层处理：

@RequestMapping(value = "/test")
        public String getRec()throws  Exception{
            List<Scenic> sceniclList=esService.getScenicFromTitle("博来");//调用Service完成搜索
            if(scenicList!=null && scenicList.size()>0){//搜索到结果打印到前端
                return scenicList.toString();
            }else{
                return "no data.";
            }
            
            return  "hello";
        }

二、SpringBoot 客户端配置使用

1、pom文件配置

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

2、yml文件配置

spring:
      elasticsearch:
        rest:
          uris: http://host:9200
          username: elastic
          password: elastic

3、继承data的接口

import org.springframework.data.repository.CrudRepository;
    import java.util.List;
    
    public interface EsRepository extends CrudRepository<Scenic,String>{
        List<Scenic> findByTitleLike(String title);
    }

4、实现Data的接口

import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import java.util.List;
    
    @Service
    public class EsService {
        @Autowired
        EsRepository esRepository;
    
        public List<Scenic> getScenicFromTitle(String keyword){
            return  esRepository.findByTitleLike(keyword);
        }
    }

5、控制层入口

import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import java.util.List;
    
    @RestController
    public class TestController {
        @Autowired
        EsService esService;
        @RequestMapping(value = "/test")
        public String getRec()throws  Exception{
            List<Scenic> scenicList =esService.getScenicFromTitle("再来");//调用Service完成搜索
            if(scenicList !=null && scenicList.size()>0){//搜索到结果打印到前端
                return scenicList.toString();
            }else{
                return "no data.";
            }
        }
    }

到此，两种客户端分享完毕，下篇通过DSL语句分享es的基础操作，敬请期待！