现在的elasticsearch已经更新到8.2版本，网络上的学习资料基本都是8.0以下的版本。elasticsearch官方在8.0版本以后，已经舍弃了High level rest clint Api，推荐使用java clint api。所以再参照8.0以下版本的资料进行学习已经非常不适合。依据如下图1-1：
由于本人在学习过程中，查找网上学习资料都是8.0以下的资料，许多地方都不适用，非常痛苦。所以在此记录本人在学习过程中的知识，以便后面学习8.0以上版本的同学有个参照的资料。
elasticsearch的下载安装基本都差不多，这里就不过多赘述，直接从springboot集成elasticsearch开始
安装依赖
新建springboot项目，在pom.xml文件中添加依赖，这里使用的es版本是8.1.1版本，各位道友使用8.0以上版本均可，将8.1.1替换成你本地下载的es版本就行。
co.elastic.clients
elasticsearch-java
8.1.1
org.jsoup
jsoup
1.10.2
本人完整的pom.xml依赖
4.0.0
com.ck.nbplus.elasticsearch
elasticsearch
0.0.1-SNAPSHOT
elasticsearch
Demo project for Spring Boot
1.8
8.1.1
UTF-8
UTF-8
2.3.7.RELEASE
org.springframework.boot
spring-boot-starter-data-elasticsearch
org.springframework.boot
spring-boot-starter-web
org.projectlombok
lombok
true
org.springframework.boot
spring-boot-starter-test
test
org.junit.vintage
junit-vintage-engine
co.elastic.clients
elasticsearch-java
8.1.1
jakarta.json
jakarta.json-api
2.0.1
org.springframework.boot
spring-boot-dependencies
${spring-boot.version}
pom
import
org.apache.maven.plugins
maven-compiler-plugin
3.8.1
1.8
1.8
UTF-8
org.springframework.boot
spring-boot-maven-plugin
2.3.7.RELEASE
com.ck.nbplus.elasticsearch.elasticsearch.ElasticsearchApplication
repackage
repackage
不建议直接复制，建议以官方文档为准，参照官方文档学习收获更大，不管版本怎么变都可以适应。官方文档地址：Installation | Elasticsearch Java API Client [8.2] | Elastic （加载很慢，可能加载好几遍才出来）
封装工具类
新建EsUtilConfigClint工具类
package com.ck.nbplus.elasticsearch.elasticsearch.esutil;
import co.elastic.clients.elasticsearch.ElasticsearchClient;
import co.elastic.clients.json.jackson.JacksonJsonpMapper;
import co.elastic.clients.transport.ElasticsearchTransport;
import co.elastic.clients.transport.rest_client.RestClientTransport;
import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.springframework.context.annotation.Configuration;
import java.io.IOException;
@Configuration
public class EsUtilConfigClint {
/**
* 客户端
* @return
* @throws IOException
*/
public ElasticsearchClient configClint() throws IOException {
// Create the low-level client
RestClient restClient = RestClient.builder(
new HttpHost("127.0.0.1", 9200)).build();
// Create the transport with a Jackson mapper
ElasticsearchTransport transport = new RestClientTransport(
restClient, new JacksonJsonpMapper());
// 客户端
ElasticsearchClient client = new ElasticsearchClient(transport);
return client;
}
}
新建Product实体类
package com.ck.nbplus.elasticsearch.elasticsearch.dao;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
@JsonIgnoreProperties(ignoreUnknown = true)
public class Product {
private String productName;
private double price;
private int number;
public String geIndexId() {
int id = 1;
id += id;
String indesId = String.valueOf(id);
return indesId;
}
}
注意我这里使用lombok，没有的去pom.xml添加依赖，或者自己添加get、set方法。
org.projectlombok
lombok
true
测试类中新建ElasticsearchApplicationTests测试类。这里使用测试类方便测试。
测试类中代码，参照参考文档所写。
package com.ck.nbplus.elasticsearch.elasticsearch;
import co.elastic.clients.elasticsearch._types.query_dsl.MatchQuery;
import co.elastic.clients.elasticsearch._types.query_dsl.Query;
import co.elastic.clients.elasticsearch._types.query_dsl.RangeQuery;
import co.elastic.clients.elasticsearch.core.*;
import co.elastic.clients.elasticsearch.core.bulk.BulkResponseItem;
import co.elastic.clients.elasticsearch.core.search.Hit;
import co.elastic.clients.elasticsearch.core.search.TotalHits;
import co.elastic.clients.elasticsearch.core.search.TotalHitsRelation;
import co.elastic.clients.elasticsearch.indices.*;
import co.elastic.clients.elasticsearch.indices.ExistsRequest;
import co.elastic.clients.json.JsonData;
import co.elastic.clients.transport.endpoints.BooleanResponse;
import com.ck.nbplus.elasticsearch.elasticsearch.dao.Product;
import com.ck.nbplus.elasticsearch.elasticsearch.esutil.EsUtilConfigClint;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
@SpringBootTest
class ElasticsearchApplicationTests {
@Autowired
private EsUtilConfigClint clint;
/**
* 判断索引是否存在
* @throws IOException
*/
@Test
void existsIndex() throws IOException {
ExistsRequest existsRequest = new ExistsRequest.Builder().index("ouldindex").build();
BooleanResponse existsResponse = clint.configClint().indices().exists(existsRequest);
System.out.println("是否存在："+existsResponse.value());
}
/**
* 创建索引
* 创建索引时，必须是小写，否则创建报错
* @throws IOException
*/
@Test
void createIndex() throws IOException {
CreateIndexRequest createIndexRequest = new CreateIndexRequest.Builder().index("ouldindex").build();
CreateIndexResponse createIndexResponse = clint.configClint().indices().create(createIndexRequest);
System.out.println("是否成功："+createIndexResponse.acknowledged());
}
/**
* 删除索引
* @throws IOException
*/
@Test
void deleteIndex() throws IOException {
DeleteIndexRequest deleteIndexRequest = new DeleteIndexRequest.Builder().index("ouldindex").build();
DeleteIndexResponse deleteIndexResponse = clint.configClint().indices().delete(deleteIndexRequest);
System.out.println("是否成功："+deleteIndexResponse.acknowledged());
}
/**
* 同步方式
* 向索引中添加信息,此操作不存在索引时会直接创建索引，使用时需要各种校验使逻辑更严谨
* @throws IOException
*/
@Test
void setIndex() throws IOException {
Product product = new Product("帽子",44.5,9);
IndexRequest indexRequest = new IndexRequest.Builder().index("newindex")
.id(String.valueOf(product.getNumber()))
.document(product)
.build();
IndexResponse indexResponse = clint.configClint().index(indexRequest);
System.out.println(indexResponse);
}
/**
* 批量写入数据
* @throws IOException
*/
@Test
void bulkIndex() throws IOException{
List products = new ArrayList();
products.add(new Product("香烟",135,1));
products.add(new Product("瓜子",154,2));
products.add(new Product("矿泉水",613,3));
products.add(new Product("酱油",72,4));
products.add(new Product("大米",771,5));
BulkRequest.Builder bk = new BulkRequest.Builder();
int indexId = 4;
for (Product product:products) {
bk.operations(op->op.index(i->i.index("newindex")
.id(UUID.randomUUID().toString())
.document(product)));
}
BulkResponse response = clint.configClint().bulk(bk.build());
if (response.errors()) {
System.out.println("Bulk had errors");
for (BulkResponseItem item: response.items()) {
if (item.error() != null) {
System.out.println(item.error().reason());
}
}
}
}
/**
* 根据索引文档id获取文档信息
* @throws IOException
*/
@Test
void getIndexById() throws IOException {
GetRequest getRequest = new GetRequest.Builder().index("newindex")
.id("9")
.build();
GetResponse response = clint.configClint().get(getRequest, Product.class);
if (response.found()) {
Product product = response.source();
System.out.println("Product name " + product.getNumber());
System.out.println("Product price " + product.getPrice());
} else {
System.out.println("Product not found");
}
}
/**
* 简单查询文档信息
* @throws IOException
*/
@Test
void getSearch() throws IOException{
/*此处 .from(1).size(2) 表示分页查询，从第一页开始查询，大小为两条*/
SearchRequest searchRequest = new SearchRequest.Builder().index("newindex")
.query(q -> q.match(m -> m.field("productName").query("烟"))).from(1).size(2).build();
SearchResponse response = clint.configClint().search(searchRequest,Product.class);
TotalHits total = response.hits().total();
boolean isExactResult = total.relation() == TotalHitsRelation.Eq;
if (isExactResult) {
System.out.println("There are " + total.value() + " results");
} else {
System.out.println("There are more than " + total.value() + " results");
}
List<Hit> hits = response.hits().hits();
for (Hit hit: hits) {
Product product = hit.source();
System.out.println("Found product " + product.getProductName() + ", score " + hit.score());
}
}
/**
* 多条件嵌套查询文档信息
* @throws IOException
*/
@Test
void getSearchs() throws IOException{
String productName = "衣服";
double price = 115;
//按照产品名称搜索
Query byname = MatchQuery.of(m -> m.field("productName")
.query(productName))._toQuery();
//按照产品价格搜索
Query byprice = RangeQuery.of(r -> r
.field("price")
.gte(JsonData.of(price))
)._toQuery();
//结合名称和价格查询
SearchResponse response = clint.configClint().search(s -> s
.index("newindex")
.query(q -> q
.bool(b -> b
.must(byname)
.must(byprice)
)
)
.from(1)
.size(2),
Product.class
);
List<Hit> hits = response.hits().hits();
for (Hit hit : hits){
Product product = hit.source();
System.out.println(product.getName()+" "+product.getPrice());
}
}
}
