搜索引擎 restful Elasticsearch基础学习（Java API 实现增删查改）

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：

三、ES启动

启动命令：elasticsearch.bat

若能成功访问 http://loaclhost:9200，则启动成功

可通过 es-head-chrome插件查看ES后台：

启动kibana：

访问：http://localhost:5601 在开发工具中，可执行Rest命令

四、Springboot项目搭建

创建Springboot项目：

五、添加ES依赖

设置ES版本：

1.8

6.8.13

导入ES依赖，JSON依赖：

com.alibaba

fastjson

1.2.54

org.elasticsearch.client

elasticsearch-rest-high-level-client

org.elasticsearch.client

elasticsearch-rest-client

org.elasticsearch

elasticsearch

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）：

menthodur地址描述PUTlocalhost：9200/索引名称/类型名称/文档id创建文档（指定文档id）POSTlocalhost：9200/索引名称/类型名称创建文档（随机文档id）POSTlocalhost：9200/索引名称/类型名称/文档id/_update修改文档DELETElocalhost：9200/索名称/类型名称/文档id删除文档GETlocalhost：9200/索引名称/类型名称/文档id查询文档通过文档idPOSTlocalhost：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 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 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

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 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);

}

}

参考文章

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