项目中使用es（二）：使用RestHighLevelClient操作elasticsearch

写在前面

之前写了有关elasticsearch的搭建和使用springboot操作elasticsearch，这次主要简单说下使用RestHighLevelClient工具包操作es。

搭建环境和选择合适的版本

环境还是以springboot2.7.12为基础搭建的，不过这不重要，因为这次想说的是RestHighLevelClient操作elasticsearch，RestHighLevelClient版本使用的是7.6.2，还需要引入elasticsearch客户端maven配置，版本也是7.6.2.
主要maven配置：

        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.6.2</version>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.6.2</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba.fastjson2</groupId>
            <artifactId>fastjson2</artifactId>
            <version>2.0.32</version>
        </dependency>
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具体代码实现

1.首先是通过springboot实例化RestHighLevelClient对象

package com.es.demo.config;

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.context.annotation.Configuration;
import org.springframework.data.elasticsearch.repository.config.EnableElasticsearchRepositories;

import java.util.ArrayList;
import java.util.List;

@Configuration
public class ElasticsearchConfig {

    @Value("${spring.elasticsearch.uris}")
    private String urls;
    
    @Bean
    public RestHighLevelClient geClient() {
        RestHighLevelClient client = null;
        String[] split = urls.split(":");
        HttpHost httpHost = new HttpHost(split[0], Integer.parseInt(split[1]), "http");
        client = new RestHighLevelClient(RestClient.builder(httpHost));
        return client;
    }
}
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2.RestHighLevelClient的简单例子，这里我就没有抽出来公共方法，只是简单的写了一下如何使用。
首先是接口

public interface ProductHighService {

    Boolean save(ProductInfo... productInfo);

    Boolean delete(Integer id);

    ProductInfo getById(Integer id);

    List<ProductInfo> getAll();

    List<ProductInfo> query(String keyword);
}
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然后是实现

@Service
public class ProductHighServiceImpl implements ProductHighService {

    @Autowired
    private RestHighLevelClient restHighLevelClient;

    @Override
    public Boolean save(ProductInfo... productInfo) {
//        IndexRequest request = new IndexRequest();
//        for (ProductInfo info : productInfo) {
//            request.index("product-info").id(String.valueOf(info.getId()));
//            request.source(XContentType.JSON, info);
//            try {
//                IndexResponse response = restHighLevelClient.index(request, RequestOptions.DEFAULT);
//                // 打印结果信息
//                System.out.println("_index: " + response.getIndex());
//                System.out.println("id: " + response.getId());
//                System.out.println("_result: " + response.getResult());
//            } catch (IOException e) {
//                throw new RuntimeException(e);
//            }
//        }
        //循环插入/更新
//        UpdateRequest updateRequest = new UpdateRequest();
//        for (ProductInfo info : productInfo) {
//            updateRequest.index("product-info").id(String.valueOf(info.getId()));
//            updateRequest.doc(XContentType.JSON, info);
//            try {
//                UpdateResponse response = restHighLevelClient.update(updateRequest, RequestOptions.DEFAULT);
//                // 打印结果信息
//                System.out.println("_index: " + response.getIndex());
//                System.out.println("id: " + response.getId());
//                System.out.println("_result: " + response.getResult());
//            } catch (IOException e) {
//                throw new RuntimeException(e);
//            }
//        }

        //批量操作estHighLevelClient.bulk()可以包含新增，修改，删除
        BulkRequest request = new BulkRequest();
        Arrays.stream(productInfo).forEach(info -> {
            IndexRequest indexRequest = new IndexRequest();
            indexRequest.index("product-info").id(String.valueOf(info.getId()));
            try {
                //通过ObjectMapper将对象转成字符串再保存，如果不转的话存入的格式不是正常的json格式数据，不能转成对象
                ObjectMapper objectMapper = new ObjectMapper();
                String productJson = objectMapper.writeValueAsString(info);
                indexRequest.source(productJson, XContentType.JSON);
            } catch (JsonProcessingException e) {
                throw new RuntimeException(e);
            }
            request.add(indexRequest);
        });
        try {
            BulkResponse response = restHighLevelClient.bulk(request, RequestOptions.DEFAULT);
            System.out.println(response.status().getStatus());
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return null;
    }

    @Override
    public Boolean delete(Integer id) {
        DeleteRequest deleteRequest = new DeleteRequest().index("product-info").id(String.valueOf(id));
        try {
            DeleteResponse response = restHighLevelClient.delete(deleteRequest, RequestOptions.DEFAULT);
            // 打印结果信息
            System.out.println("_index: " + response.getIndex());
            System.out.println("_id: " + response.getId());
            System.out.println("result: " + response.getResult());
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return null;
    }

    @Override
    public ProductInfo getById(Integer id) {
        GetRequest getRequest = new GetRequest().index("product-info").id(String.valueOf(id));
        try {
            GetResponse response = restHighLevelClient.get(getRequest, RequestOptions.DEFAULT);
            // 打印结果信息
            System.out.println("_index: " + response.getIndex());
            System.out.println("_type: " + response.getType());
            System.out.println("_id: " + response.getId());
            System.out.println("source: " + response.getSourceAsString());
            if (StringUtils.hasLength(response.getSourceAsString())) {
                return JSONObject.parseObject(response.getSourceAsString(), ProductInfo.class);
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return null;
    }

    @Override
    public List<ProductInfo> getAll() {
        SearchRequest request = new SearchRequest();
        request.indices("product-info");
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        searchSourceBuilder.query(QueryBuilders.matchAllQuery());
        //restHighLevelClient在执行默认查询时返回条数都是10条，查询所有的时候要设置上size
        //lasticsearch exception [type=illegal_argument_exception, reason=Result window is too large, from + size must be less than or equal to: [10000] but was [1000000]
        //size不能设置查过10000条，
        searchSourceBuilder.size(1000);
        request.source(searchSourceBuilder);
        List<ProductInfo> result = new ArrayList<>();
        try {
            SearchResponse response = restHighLevelClient.search(request, RequestOptions.DEFAULT);
            response.getHits().forEach(e -> {
                ProductInfo productInfo = JSONObject.parseObject(e.getSourceAsString(), ProductInfo.class);
                result.add(productInfo);
            });
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return result;
    }

    @Override
    public List<ProductInfo> query(String keyword) {
        //https://blog.csdn.net/qq_38826019/article/details/121344376
        SearchRequest request = new SearchRequest();
        request.indices("product-info");
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        searchSourceBuilder.query(QueryBuilders.matchQuery("productName", keyword));
        searchSourceBuilder.query(QueryBuilders.matchQuery("description", keyword));
        //分页
//        searchSourceBuilder.from();
//        searchSourceBuilder.size()
        request.source(searchSourceBuilder);
        List<ProductInfo> result = new ArrayList<>();
        try {
            SearchResponse response = restHighLevelClient.search(request, RequestOptions.DEFAULT);
            response.getHits().forEach(e -> {
                ProductInfo productInfo = JSONObject.parseObject(e.getSourceAsString(), ProductInfo.class);
                result.add(productInfo);
            });
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return result;
    }
}
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这里注意一点：restHighLevelClient在执行查询的时候默认返回10条，所以如果查询数量大于10条的话需要手动设置sizesearchSourceBuilder.size(1000)，但是size的大小不能查过10000条，es有限制查询记录数不能超过10000，如果设置过大就会报错：elasticsearch exception [type=illegal_argument_exception, reason=Result window is too large, from + size must be less than or equal to: [10000] but was [1000000]

最后

别的的话好像没有遇到什么问题，因为我就是写了一个简单的demo测试一下
demo地址：https://gitee.com/wdvc/es-demo.git，有兴趣可以看下。