Spring Boot整合ElasticSearch7
ElasticSearch的Java客户端
官方文档：https://www.elastic.co/guide/en/elasticsearch/client/index.html
Java REST 客户端有两种风格：
- Java 低级 REST 客户端：Elasticsearch 的官方低级客户端。它允许通过 http 与 Elasticsearch 集群通信。将请求编组和响应取消编组给用户。它与所有 Elasticsearch 版本兼容。
- Java 高级 REST 客户端：Elasticsearch 的官方高级客户端。基于低级客户端，它公开 API 特定方法并处理请求编组和响应解组。
一般使用高级的REST客户端，因为它对低级的REST客户端做了封装，比较方便。
Java高级 REST Client 至少需要 Java 1.8 并且依赖于 Elasticsearch 核心项目。客户端版本与开发客户端的 Elasticsearch 版本相同。
Java高级 REST Client 的Maven仓库
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
<version>7.14.2</version>
</dependency>
Spring Boot整合ElasticSearch
创建Spring Boot项目，引入ElasticSearch的Java 高级 REST 客户端依赖，并修改Elasticsearch 核心项目依赖的版本，因为在Spring Boot项目的父项目依赖管理中定义了ElasticSearch核心项目依赖的版本，所以要修改为自己的版本
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.4.11</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>demo-elasticsearch</artifactId>
<version>0.0.1-SNAPSHOT</version>
<properties>
<java.version>1.8</java.version>
<elasticsearch.version>7.14.0</elasticsearch.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
<version>7.14.0</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
配置RestHighLevelClient 和 RequestOptions
@Configuration
public class ElasticSearchConfig {
public static final RequestOptions COMMON_OPTIONS;
static {
RequestOptions.Builder builder = RequestOptions.DEFAULT.toBuilder();
/* builder.addHeader("Authorization", "Bearer " + TOKEN);
builder.setHttpAsyncResponseConsumerFactory(
new HttpAsyncResponseConsumerFactory
.HeapBufferedResponseConsumerFactory(30 * 1024 * 1024 * 1024));*/
COMMON_OPTIONS = builder.build();
}
@Bean
public RestHighLevelClient restHighLevelClient() {
return new RestHighLevelClient(
RestClient.builder(
new HttpHost("127.0.0.1", 9200, "http")));
}
}
保存数据
可以保存数据，也可以修改数据，多次保存同一个数据version值会增加
@SpringBootTest
class DemoElasticsearchApplicationTests {
@Autowired
private RestHighLevelClient restClient;
@Test
void indexRequest() throws IOException {
//创建索引
IndexRequest request = new IndexRequest("users");
//数据的id
request.id("1");
User user = new User();
user.setId(1L);
user.setName("青橙");
user.setAge(25);
user.setGender("男");
String jsonString = JSON.toJSONString(user);
request.source(jsonString, XContentType.JSON);
IndexResponse response = restClient.index(request, ElasticSearchConfig.COMMON_OPTIONS);
System.out.println(response);
}
}
更新数据
当数据没有发生改变时，元数据的version值也不会增加
@SpringBootTest
class DemoElasticsearchApplicationTests {
@Autowired
private RestHighLevelClient restClient;
@Test
void updateRequest() throws IOException {
UpdateRequest request = new UpdateRequest("users", "1");
User user = new User();
user.setName("青橙ee");
String jsonString = JSON.toJSONString(user);
request.doc(jsonString, XContentType.JSON);
UpdateResponse updateResponse = restClient.update(request, ElasticSearchConfig.COMMON_OPTIONS);
System.out.println(updateResponse);
}
}
获取数据
根据文档的id来获取数据
@SpringBootTest
class DemoElasticsearchApplicationTests {
@Autowired
private RestHighLevelClient restClient;
@Test
void getRequest() throws IOException {
GetRequest request = new GetRequest("users", "1");
GetResponse response = restClient.get(request, ElasticSearchConfig.COMMON_OPTIONS);
if (response.isExists()) {
String sourceAsString = response.getSourceAsString();
User user = JSON.parseObject(sourceAsString, User.class);
System.out.println(user);
} else {
System.out.println("没有搜索到数据");
}
}
}
删除数据
根据文档id删除数据
@SpringBootTest
class DemoElasticsearchApplicationTests {
@Autowired
private RestHighLevelClient restClient;
@Test
void deleteRequest() throws IOException {
DeleteRequest deleteRequest = new DeleteRequest("users", "1");
DeleteResponse deleteResponse = restClient.delete(deleteRequest, ElasticSearchConfig.COMMON_OPTIONS);
ReplicationResponse.ShardInfo shardInfo = deleteResponse.getShardInfo();
if (shardInfo.getTotal() != shardInfo.getSuccessful()) {
System.out.println("删除数据成功");
}
}
}
复杂检索
构建一个复杂的检索，并获取检索到的数据：文档元数据、文档数据、分析信息。如下
GET /bank/_search
{
"query": {
"match": {
"address": "mill"
}
},
"aggs": {
"ageAgg": {
"terms": {
"field": "age",
"size": 10
}
},
"balanceAvg": {
"avg": {
"field": "balance"
}
}
}
}
@SpringBootTest
class DemoElasticsearchApplicationTests {
@Autowired
private RestHighLevelClient restClient;
@Test
void searchRequest() throws IOException {
//创建索引请求
SearchRequest searchRequest = new SearchRequest();
//指定DSL检索条件
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
//检索条件：address中包含mill的
MatchQueryBuilder matchQuery = QueryBuilders.matchQuery("address", "mill");
searchSourceBuilder.query(matchQuery);
//聚合：根据年龄分布进行聚合
TermsAggregationBuilder ageAgg = AggregationBuilders.terms("ageAgg").field("age").size(10);
searchSourceBuilder.aggregation(ageAgg);
//聚合：根据平均薪资进行聚合
AvgAggregationBuilder balanceAvg = AggregationBuilders.avg("balanceAvg").field("balance");
searchSourceBuilder.aggregation(balanceAvg);
searchRequest.source(searchSourceBuilder);
//执行检索
SearchResponse searchResponse = restClient.search(searchRequest, ElasticSearchConfig.COMMON_OPTIONS);
//获取检索结果
SearchHits hits = searchResponse.getHits();
//检索到的文档总数
long value = hits.getTotalHits().value;
System.out.println("检索到的文档总数" + value);
//文档最大分数
float maxScore = hits.getMaxScore();
System.out.println("文档最大分数" + maxScore);
SearchHit[] searchHits = hits.getHits();
for (SearchHit hit : searchHits) {
//文档所属索引
String index = hit.getIndex();
System.out.println("文档所属索引" + index);
//文档id
String id = hit.getId();
System.out.println("文档id" + id);
//文档得分
float score = hit.getScore();
System.out.println("文档得分" + score);
//文档数据
String sourceAsString = hit.getSourceAsString();
AccountDTO accountDTO = JSON.parseObject(sourceAsString, AccountDTO.class);
System.out.println("文档内容" + accountDTO);
//获取检索到的分析信息
Aggregations aggregations = searchResponse.getAggregations();
//获取年龄分布聚合的分析信息
Terms ageAggregation = aggregations.get("ageAgg");
for (Terms.Bucket bucket : ageAggregation.getBuckets()) {
Integer key = Integer.parseInt(bucket.getKey().toString());
long docCount = bucket.getDocCount();
System.out.println("key: " + key + ", docCount: " + docCount);
}
//获取平均薪资的聚合分析信息
Avg balanceAggregation = aggregations.get("balanceAvg");
double avgValue = balanceAggregation.getValue();
System.out.println("平均薪资是：" + avgValue);
}
}
}
