[Java知识库]springboot集成elasticsearch

本文简单记录下 springboot 集成 elasticsearch 7.x 的方法

引入maven依赖

这里放弃了使用spring-boot-starter-data-elasticsearch（这个可能会受 springboot 版本和 elasticsearch 版本影响），而是直接使用rest-high-level-client。

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

将RestHighLevelClient纳入spring容器管理

@Configuration
public class ElasticSearchClientConfig {
    @Bean
    public RestHighLevelClient restHighLevelClient() {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("127.0.0.1", 9200, "http")));
        return client;
    }
}

之后，在其他地方就能直接使用了：

@Autowired
@Qualifier("restHighLevelClient")
private RestHighLevelClient client;

文档操作

根据ID查询文档

使用 GetRequest

@Test
public void testGetById() throws IOException {
	GetRequest getRequest = new GetRequest("my-index", "1");
	GetResponse response = client.get(getRequest, RequestOptions.DEFAULT);
	log.info("result exists : " + response.isExists());
	log.info("response : " + response.getSourceAsString()); // 格式是json字符串
}

创建文档

使用 IndexRequest

@Test
public void testCreateDocument() throws IOException {
	DataEntity entity = new DataEntity();
	// 设置entity属性
	......

	IndexRequest indexRequest = new IndexRequest("my-index").id(entity.getId());
	indexRequest.source(JSON.toJSONString(entity), XContentType.JSON);
	IndexResponse response = client.index(indexRequest, RequestOptions.DEFAULT);
	log.info("id : " + response.getId());
	log.info("operate result : " + response.getResult());
}

批量创建文档

比如将数据库中的数据导入es中时，可以使用批量创建

通过 BulkRequest 来操作

@Test
public void testBulkCreateDocument() throws IOException {
	// 手动初始化，或者从数据库中查询
	List<DataEntity> list = ......

	BulkRequest bulkRequest = new BulkRequest();
	list.forEach(entity -> {
		EsDataEntity esDataEntity = new EsDataEntity();
		BeanUtils.copyProperties(entity, esDataEntity);
        // 这里设置id为业务的id。也可以不设置，由es自动创建
		IndexRequest indexRequest = new IndexRequest("my-index").id(esDataEntity.getId());
		// 创建时需要传入json字符串
		indexRequest.source(JSON.toJSONString(esDataManage), XContentType.JSON);
		// 将IndexRequest添加到BulkRequest
		bulkRequest.add(indexRequest);
	});
	
	// 执行批量插入
	BulkResponse response = client.bulk(bulkRequest, RequestOptions.DEFAULT);
	log.info("BulkResponse : " + JSON.toJSONString(response));
}

根据ID更新文档

使用 UpdateRequest

@Test
public void testUpdateDocument() throws IOException {
	GetRequest getRequest = new GetRequest("my-index", "1");
	GetResponse getResponse = client.get(getRequest, RequestOptions.DEFAULT);
	if (!getResponse.isExists()) {
		log.error("id:[1]不存在！");
		return;
	}
	// 将json转为java对象
	EsDataEntity esDataEntity = JSON.parseObject(getResponse.getSourceAsString(), EsDataEntity.class);
	// 随便修改个字段值
	esDataEntity.setRemark("Vehicle");
	// 构造函数中传入索引和文档id
	UpdateRequest updateRequest = new UpdateRequest(getResponse.getIndex(), getResponse.getId());
	// java对象转为json
	updateRequest.doc(JSON.toJSONString(esDataEntity), XContentType.JSON);
	// 执行更新
	UpdateResponse response = client.update(updateRequest, RequestOptions.DEFAULT);
	log.info("id : " + response.getId());
	log.info("operate result : " + response.getResult());
}

根据ID删除文档

使用 DeleteRequest

@Test
public void testDeleteDocument() throws IOException {
	DeleteRequest deleteRequest = new DeleteRequest("my-index", "1");
	DeleteResponse response = client.delete(deleteRequest, RequestOptions.DEFAULT);
	log.info("id : " + response.getId());
	log.info("operate result : " + response.getResult());
}

查询

查询就太多了，随便贴一个作为记录：

@Test
void query() {
	SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
	// bool查询
	BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
	boolQueryBuilder.must(QueryBuilders.matchQuery("labels.container_name", "train-py-test"));
	boolQueryBuilder.must(QueryBuilders.matchQuery("name", "container_memory_rss"));
	boolQueryBuilder.must(QueryBuilders.rangeQuery("@timestamp")
			.gte("2022-03-31 07:59:00")
			.lte("2022-03-31 08:59:00")
			.format("yyyy-MM-dd HH:mm:ss"));
	sourceBuilder.query(boolQueryBuilder);
	sourceBuilder.from(0); // 从第几条开始
	sourceBuilder.size(120); // 需要获取的数量
	sourceBuilder.sort("@timestamp", SortOrder.DESC); // 按时间倒序排序

	SearchRequest request = new SearchRequest();
	request.indices("my-index"); // 索引
	request.source(sourceBuilder);
	try {
		SearchResponse response = client.search(request, RequestOptions.DEFAULT);
		// 业务对象集合
		List<Metrics> metricsList = new ArrayList<>();
		for (SearchHit hit : response.getHits().getHits()) {
			// 返回的结果是一个json字符串
			String json = hit.getSourceAsString();
			// 转为JSONObject对象
			JSONObject jsonObject = JSONObject.parseObject(json);
			// json转为需要的java对象
			Metrics metrics = JSON.parseObject(json, Metrics.class);
			metrics.setTimestamp(DateUtil.parseUTC((String)jsonObject.get("@timestamp")));
			System.out.println(JSON.toJSONString(metrics));
			metricsList.add(metrics);
		}
	} catch (IOException e) {
		e.printStackTrace();
	}
}