Springboot 整合 Elasticsearch（三）：使用RestHighLevelClient操作ES ①

📁 前情提要：

Springboot 整合 Elasticsearch（一）：Linux下安装 Elasticsearch 8.x

Springboot 整合 Elasticsearch（二）：使用HTTP请求来操作ES

一、Springboot 整合 Elasticsearch

1、pom.xml 中添加依赖

2、application.yml 中添加配置项

3、RestHighLevelClient API介绍

3.1、连接配置类

3.2、检查索引是否存在

3.2、创建索引

3.3、删除索引

3.4、增加文档

3.5、按主键更新文档内容

3.6、按主键删除文档内容

3.7、批量添加文档

一、Springboot 整合 Elasticsearch

1、pom.xml 中添加依赖

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

2、application.yml 中添加配置项

spring:
  elasticsearch:
    rest:
      uris: 192.168.1.250:9200

3、RestHighLevelClient API介绍

3.1、连接配置类

@Component
public class EsConfig {

    @Value("${spring.elasticsearch.rest.uris}")
    private String uris;

    /**
     * 高版本客户端
     *
     * @return
     */
    @Bean
    public RestHighLevelClient restHighLevelClient() {
        String[] split = uris.split(",");
        HttpHost[] httpHostArray = new HttpHost[split.length];
        for (int i = 0; i < split.length; i++) {
            String item = split[i];
            httpHostArray[i] = new HttpHost(item.split(":")[0], Integer.parseInt(item.split(":")[1]), "http");
        }
        // 创建RestHighLevelClient客户端
        return new RestHighLevelClient(RestClient.builder(httpHostArray));
    }
}

3.2、检查索引是否存在

    @Test
    public void checkIndex() {
        try {
            String indexName = "forest";
            boolean exists = esConfig.restHighLevelClient().indices().exists(new GetIndexRequest(indexName), RequestOptions.DEFAULT);
            System.out.println("exists:" + exists);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

3.2、创建索引

    @Test
    public void createIndex() {
        try {
            // 创建名为“森林”的索引
            String indexName = "forest";
            if (checkIndex(indexName)) {
                log.info("已存在名为{}的索引", indexName);
                return;
            }
            CreateIndexRequest createIndexRequest = new CreateIndexRequest(indexName);
            CreateIndexResponse createIndexResponse = esConfig.restHighLevelClient().indices().create(createIndexRequest, RequestOptions.DEFAULT);
            System.out.println("已创建索引：" + createIndexResponse.index());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public boolean checkIndex(String indexName) {
        boolean exists = false;
        try {
            exists = esConfig.restHighLevelClient().indices().exists(new GetIndexRequest(indexName), RequestOptions.DEFAULT);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return exists;
    }

3.3、删除索引

    @Test
    public void deleteIndex() {
        String indexName = "forest";
        DeleteIndexRequest deleteIndexRequest = new DeleteIndexRequest(indexName);
        // 发送delete请求
        try {
            AcknowledgedResponse response = esConfig.restHighLevelClient().indices().delete(deleteIndexRequest, RequestOptions.DEFAULT);
            System.out.println("是否已删除：" + response.isAcknowledged());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

3.4、增加文档

    @Test
    public void createDoc() {
        try {
            String indexName = "forest";
            ForestDoc forestDoc = new ForestDoc();
            forestDoc.setId(001L).setTitle("枫树").setImages("http://fengshu.jpg").setPrice(300.00).setInventory(600);

            // 创建索引请求对象
            IndexRequest indexRequest = new IndexRequest(indexName);
            indexRequest.id(forestDoc.getId().toString());
            indexRequest.source(JSON.toJSONString(forestDoc), XContentType.JSON);
            // 设置数据刷新策略
            indexRequest.setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE);

            IndexResponse index = esConfig.restHighLevelClient().index(indexRequest, RequestOptions.DEFAULT);
            System.out.println("状态：" + index.status().getStatus());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

⚠️RefreshPolicy 刷新策略，是WriteRequest接口中的一个内部枚举
① IMMEDIATE:
请求向ElasticSearch提交了数据，立即进行数据刷新，然后再结束请求。
优点：实时性高、操作延时短。
缺点：资源消耗高。
② WAIT_UNTIL:
请求向ElasticSearch提交了数据，等待数据完成刷新，然后再结束请求。
优点：实时性高、操作延时长。
缺点：资源消耗低。
③ NONE:
默认策略。
请求向ElasticSearch提交了数据，不关系数据是否已经完成刷新，直接结束请求。
优点：操作延时短、资源

3.5、按主键更新文档内容

修改 id 为 2 的 images字段内容

    @Test
    public void updateDocById() {
        try {
            String indexName = "forest";
            String id = "2";
            UpdateRequest updateRequest = new UpdateRequest(indexName, id);
            Map<String, Object> map = new HashMap<>();
            map.put("images", "http://baihuashu.jpg");
            updateRequest.doc(map);
            UpdateResponse update = esConfig.restHighLevelClient().update(updateRequest, RequestOptions.DEFAULT);
            System.out.println("状态：" + update.status().getStatus());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

3.6、按主键删除文档内容

    @Test
    public void deleteDocById() {
        String indexName = "forest";
        String id = "5";
        DeleteRequest deleteRequest = new DeleteRequest(indexName,id);
        try {
            DeleteResponse delete = esConfig.restHighLevelClient().delete(deleteRequest, RequestOptions.DEFAULT);
            System.out.println("状态：" + delete.status().getStatus());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

3.7、批量添加文档

    @Test
    public void batchCreateDoc() {
        try {
            String indexName = "forest";

            List<ForestDoc> list = new ArrayList<>();

            ForestDoc forestDoc = new ForestDoc();
            forestDoc.setId(6L).setTitle("批量_柏树").setImages("http://baishu.jpg").setPrice(1100.00).setInventory(1200);
            list.add(forestDoc);

            ForestDoc forestDoc2 = new ForestDoc();
            forestDoc2.setId(7L).setTitle("批量_苹果树").setImages("http://pingguoshu.jpg").setPrice(1200.00).setInventory(1300);
            list.add(forestDoc2);

            ForestDoc forestDoc3 = new ForestDoc();
            forestDoc3.setId(8L).setTitle("批量_海棠树").setImages("http://haitangshu.jpg").setPrice(1300.00).setInventory(1400);
            list.add(forestDoc3);

            //批量导入
            BulkRequest bulk = new BulkRequest(indexName);

            for (ForestDoc doc : list) {
                IndexRequest indexRequest = new IndexRequest();
                indexRequest.id(doc.getId().toString());
                indexRequest.source(JSON.toJSONString(doc), XContentType.JSON);
                bulk.add(indexRequest);
            }
            BulkResponse bulkResponse = esConfig.restHighLevelClient().bulk(bulk, RequestOptions.DEFAULT);
            System.out.println("状态：" + bulkResponse.status().getStatus());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }