Elasticsearch基础学习（Java API 实现增删查改）-Toy模板网

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一、概述

ElasticSearch，简称为ES， ES是一个开源的高扩展的分布式全文搜索引擎。它可以近乎实时的存储、检索数据；本身扩展性很好，可以扩展到上百台服务器，处理PB级别的数据。

物理设计：
ElasticSearch 在后台把每个索引划分成多个分片，每份分片可以在集群中的不同服务器间迁移。

逻辑设计：
一个索引类型中，包含多个文档，比如说文档1，文档2，文档3。当我们索引一篇文档时，可以通过这样的一个顺序找到它: 索引 -▷ 类型 -▷ 文档ID ，通过这个组合我们就能索引到某个具体的文档。

二、环境搭建

下载安装elasticsearch-6.8.13、es-head-chrome插件。
下载ES相关插件，将插件放置plugins目录下：
es 增删查改 java,elasticsearch,学习,搜索引擎,java,restful

三、ES启动

启动命令：elasticsearch.bat
es 增删查改 java,elasticsearch,学习,搜索引擎,java,restful

若能成功访问 http://loaclhost:9200，则启动成功
es 增删查改 java,elasticsearch,学习,搜索引擎,java,restful

可通过 es-head-chrome插件查看ES后台：

es 增删查改 java,elasticsearch,学习,搜索引擎,java,restful

启动kibana：
es 增删查改 java,elasticsearch,学习,搜索引擎,java,restful

访问：http://localhost:5601
在开发工具中，可执行Rest命令
es 增删查改 java,elasticsearch,学习,搜索引擎,java,restful

四、Springboot项目搭建

创建Springboot项目：
es 增删查改 java,elasticsearch,学习,搜索引擎,java,restful

五、添加ES依赖

设置ES版本：

<properties>
   <java.version>1.8</java.version>
   <elasticsearch.version>6.8.13</elasticsearch.version>
</properties>

导入ES依赖，JSON依赖：

<dependency>
   <groupId>com.alibaba</groupId>
   <artifactId>fastjson</artifactId>
   <version>1.2.54</version>
</dependency>

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

六、编写配置类

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

七、创建索引

@Test
void testCreateIndex() throws IOException {
   HttpHost host = HttpHost.create("http://localhost:9200");
   RestClientBuilder builder = RestClient.builder(host);
   client = new RestHighLevelClient(builder);

   CreateIndexRequest request = new CreateIndexRequest("user");
   client.indices().create(request, RequestOptions.DEFAULT);

   client.close();
}

八、增删改操作

1、基本Rest命令说明（增、删、改、查命令）：

menthod	ur地址	描述
PUT	localhost：9200/索引名称/类型名称/文档id	创建文档（指定文档id）
POST	localhost：9200/索引名称/类型名称	创建文档（随机文档id）
POST	localhost：9200/索引名称/类型名称/文档id/_update	修改文档
DELETE	localhost：9200/索名称/类型名称/文档id	删除文档
GET	localhost：9200/索引名称/类型名称/文档id	查询文档通过文档id
POST	localhost：9200/索引名称/类型名称/_search	查询所有数据

2、添加文档记录

添加单条记录

@Test
void testAddDoc() throws IOException {
   // 1.要在指定索引下创建文档，所以要先创建索引，再创建文档
   IndexRequest request=new IndexRequest();
   // index()方法设置索引名；id()方法设置唯一id标识
   request.index("user").id("10001").type("text");
   // 2.创建实体类对象，填充数据
   User user=new User();
   user.setName("张三丰");
   user.setAge(30);
   // 3.利用jackson将实体类对象转换成JSON格式字符串
   request.source(JSON.toJSONString(user), XContentType.JSON);
   // 5.发送请求，获取响应结果
   IndexResponse response = client.index(request, RequestOptions.DEFAULT);
   System.out.println("_index: "+response.getIndex());
   System.out.println("_id: "+response.getId());
   System.out.println("_result: "+response.getResult());
}

批量添加记录

	@Test
	void testBulkRequest()throws IOException{

		BulkRequest bulkRequest = new BulkRequest();
		ArrayList<Employee> users = new ArrayList<>();
//		users.add(new Employee("李文",23,"研发工程师","2352"));
//		users.add(new Employee("罗文",17,"测试工程师","8732"));
//		users.add(new Employee("徐洁",22,"算法工程师","8791"));
//		users.add(new Employee("罗辑",31,"高级研发工程师","8765"));
//		users.add(new Employee("叶文洁",70,"资深研发工程师","8551"));

		users.add(new Employee("小猪佩奇",23,"猪","2"));
		users.add(new Employee("小猪",17,"佩奇","4"));
		users.add(new Employee("测试",22,"小","6"));
		users.add(new Employee("xiaozhubeiqi",31,"peiqi","8"));
		users.add(new Employee("小猪佩佩",70,"小猪佩祺过大年","10"));
		users.add(new Employee("小猪珮奇",23,"小猪佩祺过大年","12"));
		users.add(new Employee("小猪佩奇",23,"小猪佩奇过大年","14"));

		for(int i = 0;i< users.size();i++){
			bulkRequest.add(new IndexRequest("pig").id(""+(i+1)).type("pinyin")
					.source(JSON.toJSONString(users.get(i)),XContentType.JSON));
		}
		BulkResponse bulkResponse = client.bulk(bulkRequest,RequestOptions.DEFAULT);
		System.out.println(!bulkResponse.hasFailures());
	}

3、更新文档记录

@Test
void testUpdateDoc() throws IOException
{
   UpdateRequest request = new UpdateRequest("test_index","random","1");
   User user = new User("张三",18,"003");
   request.doc(JSON.toJSONString(user), XContentType.JSON);
   UpdateResponse updateResponse = client.update(request, RequestOptions.DEFAULT);
   System.out.println(updateResponse.status() == RestStatus.OK);
}

4、删除文档记录

@Test
void testDelete() throws IOException {
   HttpHost host = HttpHost.create("http://localhost:9200");
   client = new RestHighLevelClient(RestClient.builder(host));

   DeleteRequest request = new DeleteRequest("test_index","random","1");
   DeleteResponse deleteResponse = client.delete(request, RequestOptions.DEFAULT);
   System.out.println(deleteResponse.status() == RestStatus.OK);
}

九、高级查询

1、排序查询

	/**
	 * 排序查询(sort) 代码同matchAllQuery
	 * 匹配查询符合条件的所有数据，并设置分页
	 */
	@Test
	public void sortQuery() {
		try {
			// 构建查询条件
			MatchAllQueryBuilder matchAllQueryBuilder = QueryBuilders.matchAllQuery();
			// 创建查询源构造器
			SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
			searchSourceBuilder.query(matchAllQueryBuilder);
//			// 设置分页
//			searchSourceBuilder.from(0);
//			searchSourceBuilder.size(3);
			// 设置排序
			searchSourceBuilder.sort("id", SortOrder.ASC);
			// 创建查询请求对象，将查询对象配置到其中
			SearchRequest searchRequest = new SearchRequest("employee_alias");
			searchRequest.source(searchSourceBuilder);
			// 执行查询，然后处理响应结果
			SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
			// 根据状态和数据条数验证是否返回了数据
			if (RestStatus.OK.equals(searchResponse.status())) {
				SearchHits hits = searchResponse.getHits();
				for (SearchHit hit : hits) {
					// 将 JSON 转换成对象
					Employee userInfo = JSON.parseObject(hit.getSourceAsString(), Employee.class);
					// 输出查询信息
					log.info(userInfo.toString());
				}
			}
		} catch (IOException e) {
			log.error("", e);
		}
	}

2、聚合查询（一）

查询30岁以上、30岁及以下员工的平均年龄：

@Test
public void bucketQuery() {
      // 创建查询源构造器
      SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
      // 创建查询请求对象，将查询对象配置到其中
      SearchRequest searchRequest = new SearchRequest("employee");

      RangeAggregationBuilder rangeAggregationBuilder = AggregationBuilders.range("age_ranges_avg")
            .field("age")
            .addRange(0, 30)
            .addRange(31, 100).subAggregation(AggregationBuilders.avg("avgAge").field("age"));
      searchSourceBuilder.aggregation(rangeAggregationBuilder);
      searchRequest.source(searchSourceBuilder);
      SearchResponse response;
      try {
         //发起请求，获取响应结果
         response = client.search(searchRequest, RequestOptions.DEFAULT);
         //获取聚合的结果
         Aggregations aggregations = response.getAggregations();
         Aggregation aggregation = aggregations.get("age_ranges_avg");
         System.out.println(JSON.toJSONString(aggregation));
         //获取桶聚合结果
         List<? extends Range.Bucket> buckets = ((Range) aggregation).getBuckets();
         //循环遍历各个桶结果
         for (Range.Bucket bucket : buckets) {
            //分组的key
            String key = bucket.getKeyAsString();
            //分组的值
            long docCount = bucket.getDocCount();
            ParsedAvg avgAge = bucket.getAggregations().get("avgAge");

            System.out.println(key + "======平均年龄:" + avgAge.getValue() + "======数量:" + docCount);
         }
      } catch (IOException e) {
         e.printStackTrace();
      }

}

3、聚合查询（二）

	/**
	 * 聚合查询
	 * Metric 指标聚合分析
	 */
	@Test
	public void metricQuery() {
		try {
			// 构建查询条件
			MatchAllQueryBuilder matchAllQueryBuilder = QueryBuilders.matchAllQuery();
			// 创建查询源构造器
			SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
			searchSourceBuilder.query(matchAllQueryBuilder);

			// 获取最贵的商品
			AggregationBuilder maxAge = AggregationBuilders.max("maxAge").field("age");
			searchSourceBuilder.aggregation(maxAge);
			// 获取最便宜的商品
			AggregationBuilder minAge = AggregationBuilders.min("minAge").field("age");
			searchSourceBuilder.aggregation(minAge);

			// 创建查询请求对象，将查询对象配置到其中
			SearchRequest searchRequest = new SearchRequest("employee");
			searchRequest.source(searchSourceBuilder);
			// 执行查询，然后处理响应结果
			SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
			Aggregations aggregations = searchResponse.getAggregations();
			ParsedMax max = aggregations.get("maxAge");
			log.info("最年长：" + max.getValue());
			ParsedMin min = aggregations.get("minAge");
			log.info("最年轻：" + min.getValue());
		} catch (IOException e) {
			log.error("", e);
		}
	}

4、模糊查询

	//模糊查询，原理是构建DFA，查询名字中含有“文”的员工
	@Test
	public void fuzzyQuery() {
		try {
			// 构建查询条件
			SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
			searchSourceBuilder.query(QueryBuilders.fuzzyQuery("name", "洁").fuzziness(Fuzziness.AUTO));
			// 创建查询请求对象，将查询对象配置到其中
			SearchRequest searchRequest = new SearchRequest("employee");
			searchRequest.source(searchSourceBuilder);
			// 执行查询，然后处理响应结果
			SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
			// 根据状态和数据条数验证是否返回了数据
			if (RestStatus.OK.equals(searchResponse.status())) {
				SearchHits hits = searchResponse.getHits();
				for (SearchHit hit : hits) {
					// 将 JSON 转换成对象
					Employee userInfo = JSON.parseObject(hit.getSourceAsString(), Employee.class);
					// 输出查询信息
					log.info(userInfo.toString());
				}
			}
		} catch (IOException e) {
			log.error("", e);
		}
	}

5、范围查询

//查询20岁以上的员工
	@Test
	public void rangeQuery() {
		try {
			// 构建查询条件
			SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
			searchSourceBuilder.query(QueryBuilders.rangeQuery("age").gte(20));
			// 创建查询请求对象，将查询对象配置到其中
			SearchRequest searchRequest = new SearchRequest("employee");
			searchRequest.source(searchSourceBuilder);
			// 执行查询，然后处理响应结果
			SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
			// 根据状态和数据条数验证是否返回了数据
			if (RestStatus.OK.equals(searchResponse.status()) ) {
				SearchHits hits = searchResponse.getHits();
				//log.info(hits.getTotalHits().value + "");
				for (SearchHit hit : hits) {
					// 将 JSON 转换成对象
					Employee userInfo = JSON.parseObject(hit.getSourceAsString(), Employee.class);
					// 输出查询信息
					log.info(userInfo.toString());
				}
			}
		} catch (IOException e) {
			log.error("", e);
		}
	}

6、多字段查询

multi_match进行多字段匹配查询，进行权重控制文章来源地址https://www.toymoban.com/news/detail-790842.html

GET pig/_search
{
  "query": {
    "multi_match": {
      "query": "小猪佩奇",
      "fields": ["name^3","occupation"]
    }
  }
}

@Test
	public void matchQuery() {
		try {
			// 构建查询条件
			SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();

			Map<String,Float> fields = new HashMap(2);
			fields.put("name", 1.0f);
			fields.put("occupation", 1.0f);
//			QueryBuilder queryBuilder = null;
//			queryBuilder.must(QueryBuilders.multiMatchQuery("name","小猪佩奇").fields(fields).analyzer("ik_smart"));
			searchSourceBuilder.query(QueryBuilders.multiMatchQuery("小猪佩奇","name","occupation").fields(fields).analyzer("pinyin"));


			// 创建查询请求对象，将查询对象配置到其中
			SearchRequest searchRequest = new SearchRequest("pig");
			searchRequest.source(searchSourceBuilder);
			// 执行查询，然后处理响应结果
			SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
			// 根据状态和数据条数验证是否返回了数据
			if (RestStatus.OK.equals(searchResponse.status()) ) {
				SearchHits hits = searchResponse.getHits();
				for (SearchHit hit : hits) {
					// 将 JSON 转换成对象
					Employee userInfo = JSON.parseObject(hit.getSourceAsString(), Employee.class);
					// 输出查询信息
					log.info(userInfo.toString());
				}
			}
		} catch (IOException e) {
			log.error("", e);
		}
	}