一、索引库

es中的索引是指相同类型的文档集合，即mysql中表的概念
映射：索引中文档字段的约束，比如名称、类型

1、mapping属性

mapping映射是对索引库中文档的约束。类似mysql对表单字段的约束

{"id":[1, 2, 3, 4, 5],"name":{"firstname":"明","lastname":"李"}
}

type：字段数据类型，常见的类型有：
- 字符串：text（可分词的文本）、keyword（不可分词的文本，例如国家、品牌、IP地址）
- 布尔：boolean
- 日期：date
- 数值：long、short、byte、integer、double、float
- Object：对象
  es里面没有数组类型，json格式key、value，允许value有多个值。上图id字段
index：是否创建索引，默认为true。就是是否创建倒排索引，不创建之后就不能通过它搜索。
analyzer：使用那种分词器
properties：该字段的子字段，上面name

2、索引库的crud

# 建立索引库
PUT /linsy
{"mappings": {"properties": {"info": {"type": "text","analyzer": "ik_smart"},"email": {"type": "keyword","index": false},"name": {"type": "object","properties": {"firstname": {"type": "keyword"},"lastName": {"type": "keyword"}}}}}
}

查询索引库 GET /索引库名 GET /linsy
删除索引库 DELETE /索引库名

ES 禁止修改索引库字段类型及属性，会影响整个索引的结构，但是允许在原有索引库中新增字段。
注意不能新增已有字段

PUT /索引库名/_mapping
{"properties": {"新字段名": {"type": "新字段类型"}}
}

二、文档的crud

新增操作

POST /索引库名/_doc/文档id
{"字段1": "值1“,"字段2": "值2","字段3": "值3",
}

查询 GET /索引库名/_doc/文档id
删除 DELETE /索引库名/_doc/文档id

# 文档操作
# 插入
POST /linsy/_doc/1
{"age": "11","email": "linsy@linsy.work","info": "this is a first test 文档","name": {"firstname": "明","lastName": "李"}
}GET  /linsy/_doc/1DELETE /linsy/_doc/1POST /linsy/_update/1
{"doc":{"age":1111}
}

修改文档：

全量修改：删除旧文档，添加新文档。就是将上面新增的 DSL 改为 PUT

PUT /索引库名/_doc/文档id
{"字段1": "值1“,"字段2": "值2","字段3": "值3",
}

增量修改，修改指定字段

POST /索引库名/_update/文档id
{"doc":{"字段名":"新的值"}
}

三、RestClient

springboot 导入elasticsearch依赖需注意，它默认使用的版本和springboot的版本一致，你需要对应到安装在服务器上的版本。

        <dependency><groupId>org.elasticsearch.client</groupId><artifactId>elasticsearch-rest-high-level-client</artifactId></dependency>

    <properties><java.version>8</java.version><elasticsearch.version>7.17.11</elasticsearch.version></properties>

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创建索引库的mapping映射

PUT /hotel
{"mappings": {"properties": {"id":{"type": "keyword"},"name":{"type": "text","analyzer": "ik_max_word","copy_to": "all"},"address":{"type": "keyword","index": false},"price":{"type": "integer"},"score":{"type": "integer"},"brand":{"type": "keyword","copy_to": "all"},"city":{"type": "keyword"},"starName":{"type": "keyword"},"business":{"type": "keyword","copy_to": "all"},"location":{"type": "geo_point"},"pic":{"type": "keyword","index": false},"all":{"type": "text","analyzer": "ik_max_word"}}}
}

RestHighLevelClient 的使用
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        RestHighLevelClient restHighLevelClient = new RestHighLevelClient(RestClient.builder(HttpHost.create("http://http://192.168.52.150:9200")));// index的增删查CreateIndexRequest createIndexRequest = new CreateIndexRequest("linsy");createIndexRequest.source("建立索引库语句（put）", XContentType.JSON);restHighLevelClient.indices().create(createIndexRequest, RequestOptions.DEFAULT);restHighLevelClient.indices().delete(new DeleteIndexRequest("要删除的索引库名"), RequestOptions.DEFAULT);// 判断是否存在boolean b = restHighLevelClient.indices().exists(new GetIndexRequest("索引库名"), RequestOptions.DEFAULT);

es8.x已经弃用了RestHighLevelClient
官方创建RestClient文档

文档的crud
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查询文档

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    @Autowiredprivate IHotelService iHotelService;@BeforeEachpublic void before() {restHighLevelClient = new RestHighLevelClient(RestClient.builder(HttpHost.create("http://192.168.52.150:9200")));}@AfterEachpublic void after() throws IOException {restHighLevelClient.close();}@Testpublic void addDocumentTest() throws IOException {Hotel hotel = iHotelService.getById(61075);HotelDoc hotelDoc = new HotelDoc(hotel);IndexRequest indexRequest = new IndexRequest("hotel").id(hotel.getId().toString());indexRequest.source(JSON.toJSONString(hotelDoc), XContentType.JSON);restHighLevelClient.index(indexRequest, RequestOptions.DEFAULT);}@Testpublic void queryDocumentTest() throws IOException {GetResponse getResponse = restHighLevelClient.get(new GetRequest("hotel", "61075"), RequestOptions.DEFAULT);String json = getResponse.getSourceAsString();System.out.println(json);}@Testpublic void updateDocumentTest() throws IOException {UpdateRequest updateRequest = new UpdateRequest("hotel", "61075");updateRequest.doc("city", "北京","score", "90");restHighLevelClient.update(updateRequest, RequestOptions.DEFAULT);}@Testpublic void deleteDocumentTest() throws IOException {restHighLevelClient.delete(new DeleteRequest("hotel", "61075"), RequestOptions.DEFAULT);}@Testpublic void batchAdd() throws IOException {BulkRequest bulkRequest = new BulkRequest();List<Hotel> list = iHotelService.list();for (Hotel hotel : list) {HotelDoc hotelDoc = new HotelDoc(hotel);bulkRequest.add(new IndexRequest("hotel").id(hotel.getId().toString()).source(JSON.toJSONString(hotelDoc), XContentType.JSON));}restHighLevelClient.bulk(bulkRequest, RequestOptions.DEFAULT);}