目录
网上教程多是Elasticsearch旧版本，很多方法已弃用，本文以Elasticsearch 7.10.1，SpringBoot 2.3.6.RELEASE为例说明如何整合：
一、添加pom依赖
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.um.elasticsearch</groupId>
<artifactId>elasticsearch</artifactId>
<version>1.0.0-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-elasticsearch</artifactId>
</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>二、application.yml文件配置
spring:
elasticsearch:
rest:
uris: http://10.211.55.8:9200三、实体类及注解
Spring Data通过注解来声明字段的映射属性，有下面的三个注解：
@Document作用在类，标记实体类为文档对象，一般有四个属性- indexName：对应索引库名称
- shards：分片数量，默认5
- replicas：副本数量，默认1
@Id作用在成员变量，标记一个字段作为id主键@Field作用在成员变量，标记为文档的字段，并指定字段映射属性：- type：字段类型，取值是枚举：FieldType
- index：是否索引，布尔类型，默认是true
- store：是否存储，布尔类型，默认是false
- analyzer：分词器名称：ik_max_word
示例代码：
@Document(indexName = "item", shards = 1, replicas = 0)
public class Item {
@Id
private Long id;
@Field(type = FieldType.Text, analyzer = "ik_max_word")
private String title;
@Field(type = FieldType.Keyword)
private String category;
@Field(type = FieldType.Keyword)
private String brand;
@Field(type = FieldType.Double)
private Double price;
@Field(type = FieldType.Keyword, index = false)
private String images;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getCategory() {
return category;
}
public void setCategory(String category) {
this.category = category;
}
public String getBrand() {
return brand;
}
public void setBrand(String brand) {
this.brand = brand;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
public String getImages() {
return images;
}
public void setImages(String images) {
this.images = images;
}
}四、Elasticsearch索引操作
1、创建索引
@SpringBootTest
@RunWith(SpringRunner.class)
public class ElasticsearchTest {
@Autowired
private ElasticsearchRestTemplate elasticsearchRestTemplate;
@Test
public void testCreateIndex(){
IndexOperations indexOperations = elasticsearchRestTemplate.indexOps(Item.class);
Document mapping = indexOperations.createMapping();
indexOperations.putMapping(mapping);
}
}2、删除索引
@Test
public void testDeleteIndex() {
IndexOperations indexOperations = elasticsearchRestTemplate.indexOps(Item.class);
indexOperations.delete();
}五、Elasticsearch文档操作
1、新增/修改文档
定义接口ItemRepository继承ElasticsearchRepository
public interface ItemRepository extends ElasticsearchRepository<Item, Long> {
List<Item> findByTitle(String title);
List<Item> findByPriceBetween(Double d1,Double d2);
}新增文档
@Test
public void testCreate() {
Item item = new Item(1L, "小米手机7", " 手机", "小米", 3499.00, "http://image.leyou.com/13123.jpg");
itemRepository.save(item);
}2、删除文档
@Test
public void testDelete() {
itemRepository.deleteById(1L);
}3、基本查询
@Test
public void testFind() {
Iterable<Item> items = itemRepository.findAll(Sort.by("price").descending());
items.forEach(System.out::println);
}
@Test
public void testFindByTitle() {
List<Item> items = itemRepository.findByTitle("手机");
items.forEach(System.out::println);
}
@Test
public void testFindByPriceBetween() {
List<Item> items = itemRepository.findByPriceBetween(3699D, 4499D);
items.forEach(System.out::println);
}4、高级查询
@Test
public void testSearch() {
NativeSearchQueryBuilder queryBuilder = new NativeSearchQueryBuilder();
queryBuilder.withQuery(QueryBuilders.matchQuery("title", "手机"));
int page = 0;
int size = 1;
queryBuilder.withPageable(PageRequest.of(page, size));
SearchHits<Item> hits = elasticsearchRestTemplate.search(queryBuilder.build(), Item.class);
List<Item> items = hits.stream().map(SearchHit::getContent).collect(Collectors.toList());
items.forEach(System.out::println);
}5、聚合查询
@Test
public void testAgg() {
// 初始化自定义查询构建器
NativeSearchQueryBuilder queryBuilder = new NativeSearchQueryBuilder();
// 添加聚合，嵌套聚合求平均值
queryBuilder.addAggregation(AggregationBuilders.terms("brandAgg").field("brand")
.subAggregation(AggregationBuilders.avg("price_avg").field("price")));
// 添加结果集过滤，不包括任何字段
queryBuilder.withSourceFilter(new FetchSourceFilter(new String[]{}, null));
// 执行聚合查询，获取分组数据
SearchHits<Item> searchHits = elasticsearchRestTemplate.search(queryBuilder.build(), Item.class);
Terms terms = (Terms) searchHits.getAggregations().asMap().get("brandAgg");
List<? extends Terms.Bucket> buckets = terms.getBuckets();
buckets.forEach(bucket -> {
System.out.println(bucket.getKeyAsString());
System.out.println(bucket.getDocCount());
Map<String, Aggregation> stringAggregationMap = bucket.getAggregations().asMap();
Avg price_avg = (Avg) stringAggregationMap.get("price_avg");
System.out.println(price_avg.getValue());
});
}
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