使用Springboot整合Elasticsearch

全文搜索引擎

全文搜索引擎是目前广泛应用的主流搜索引擎，也称为全文检索。它的工作原理是计算机索引程序通过扫描文章中的每一个词，对每一个词建立一个索引，指明该词在文章中出现的次数和位置，当用户查询时，检索程序就根据事先建立的索引进行查找，并将查找的结果反馈给用户的检索方式。这个过程类似于通过字典中的检索字表查字的过程。

Springboot整合Elasticsearch:

步骤：

1. 创建一个SpringBoot工程，选择以下模块：Lombok、Web、Spring Data Elasticsearch

2. 编辑application.yml文件

spring:elasticsearch:uris: http://localhost:9200

3.基本操作

使用Spring Data Elasticsearch提供的工具类：ElasticsearchRestTemplate

常用注解：

• @Document 标记实体类为文档对象

• @Id 标记为文档id

• @Field 标记为文档字段

@Data
@AllArgsConstructor
@NoArgsConstructor
@Document(indexName = "student") //标记实体类为文档对象，并指定索引名称
public class Student implements Serializable {@Id@Field(type = FieldType.Keyword) //标记为文档id，不分词private Integer id;@Field(type = FieldType.Text) // 标记为文档字段，分词private String name;@Field(type = FieldType.Integer)  //标记为文档字段，不分词private Integer age;@Field(type = FieldType.Text)private String sex;@Field(type = FieldType.Text)private String school;
}

编写创建索引Controller:

@RestController
@RequiredArgsConstructor
@RequestMapping("index")
public class IndexController {private final ElasticsearchRestTemplate restTemplate;/*** 创建索引*/@GetMapping("/create")public String create(){IndexOperations indexOperations = restTemplate.indexOps(Student.class);indexOperations.create();return "OK!";}
}

编写存入，并且获取文档Controller

@RestController
@RequiredArgsConstructor
@RequestMapping("doc")
public class DocController {private final ElasticsearchRestTemplate restTemplate;@GetMapping("/create")public String create(){restTemplate.save(new Student(1,"zhangsan",18,"男","Beijing"));return "success……";}@GetMapping("/batch")public String batch(){ArrayList<Student> list = new ArrayList<>();list.add(new Student(2,"Lisi",19,"男","北京大学"));list.add(new Student(3,"Wanger",29,"男","清华大学"));list.add(new Student(4,"Mazi",39,"男","本稻田大学"));list.add(new Student(5,"Waibozi",15,"女","东京大学"));list.add(new Student(6,"Yuzhanao",18,"男","北京大学"));restTemplate.save(list);return "batch====>success……";}@RequestMapping("/{id}")public Student findById(@PathVariable Integer id){Student student = restTemplate.get(id.toString(),Student.class);return student;}@RequestMapping("/all")public List<Student> findAll(){SearchHits<Student> hits = restTemplate.search(Query.findAll(),Student.class);System.out.println(hits.getTotalHits()); //总个数List<Student> list = hits.stream().map(hit -> hit.getContent()).collect(Collectors.toList());return list;}
}