二、ElasticSearch基础语法

一、简单了解ik分词器(分词效果)

这个是底层自带的不属于ik分词，ik分词器属于第三方分词器

1.standard(单字分词器，es默认分词器)

POST _analyze
{
  "analyzer":"standard",
  "text":"我爱学搜索引擎"
}

效果（把每一个字都拆分，每个字都被分词了）

{
  "tokens" : [
    {
      "token" : "我",
      "start_offset" : 0,
      "end_offset" : 1,
      "type" : "",
      "position" : 0
    },
    {
      "token" : "爱",
      "start_offset" : 1,
      "end_offset" : 2,
      "type" : "",
      "position" : 1
    },
    {
      "token" : "学",
      "start_offset" : 2,
      "end_offset" : 3,
      "type" : "",
      "position" : 2
    },
    {
      "token" : "搜",
      "start_offset" : 3,
      "end_offset" : 4,
      "type" : "",
      "position" : 3
    },
    {
      "token" : "索",
      "start_offset" : 4,
      "end_offset" : 5,
      "type" : "",
      "position" : 4
    },
    {
      "token" : "引",
      "start_offset" : 5,
      "end_offset" : 6,
      "type" : "",
      "position" : 5
    },
    {
      "token" : "擎",
      "start_offset" : 6,
      "end_offset" : 7,
      "type" : "",
      "position" : 6
    }
  ]
}

2.ik_smart分词(粗粒度的拆分)

和单字分词器的区别，就是按照比较粗的粒度去分词，把搜索引擎当成一个词来分词

 POST _analyze
{
  "analyzer":"ik_smart",
  "text":"我爱学搜索引擎"
}

效果

{
  "tokens" : [
    {
      "token" : "我",
      "start_offset" : 0,
      "end_offset" : 1,
      "type" : "CN_CHAR",
      "position" : 0
    },
    {
      "token" : "爱",
      "start_offset" : 1,
      "end_offset" : 2,
      "type" : "CN_CHAR",
      "position" : 1
    },
    {
      "token" : "学",
      "start_offset" : 2,
      "end_offset" : 3,
      "type" : "CN_CHAR",
      "position" : 2
    },
    {
      "token" : "搜索引擎",
      "start_offset" : 3,
      "end_offset" : 7,
      "type" : "CN_WORD",
      "position" : 3
    }
  ]
}

3.ik_max_word分词器（最细粒度拆分）

按照最细粒度进行分词，把认为能组成一个词的情况都拆分。

POST _analyze
{
  "analyzer":"ik_max_word",
  "text":"我爱学搜索引擎"
}

效果

{
  "tokens" : [
    {
      "token" : "我",
      "start_offset" : 0,
      "end_offset" : 1,
      "type" : "CN_CHAR",
      "position" : 0
    },
    {
      "token" : "爱",
      "start_offset" : 1,
      "end_offset" : 2,
      "type" : "CN_CHAR",
      "position" : 1
    },
    {
      "token" : "学",
      "start_offset" : 2,
      "end_offset" : 3,
      "type" : "CN_CHAR",
      "position" : 2
    },
    {
      "token" : "搜索引擎",
      "start_offset" : 3,
      "end_offset" : 7,
      "type" : "CN_WORD",
      "position" : 3
    },
    {
      "token" : "搜索",
      "start_offset" : 3,
      "end_offset" : 5,
      "type" : "CN_WORD",
      "position" : 4
    },
    {
      "token" : "索引",
      "start_offset" : 4,
      "end_offset" : 6,
      "type" : "CN_WORD",
      "position" : 5
    },
    {
      "token" : "引擎",
      "start_offset" : 5,
      "end_offset" : 7,
      "type" : "CN_WORD",
      "position" : 6
    }
  ]
}

---

二、指定默认分词器

1.为索引指定默认分词器

创建一个索引（mysql中对应database），名为test_index_database
指定默认分词器为：ik_max_word

PUT /test_index_database
{
  "settings":{
      "index":{
        "analysis.analyzer.default.type":"ik_max_word"
      }
  }
}

---

三、ES操作数据

在7.x版本以后类型默认为_doc

1.概述

es是面向文档的，它可以储存整个对象或者文档，对该文档进行索引、搜索、排序、过滤。
使用json作为文档序列化格式

2.创建索引

PUT /test_index01

3.查询索引

GET /test_index01

查询信息如下
其中number_of_shards(分片数量)
number_of_replicas(副本数量)
es7.6.1版本默认的分片和副本数量为1，这个默认数量和你es的版本有关系。可能其他版本默认不是1

{
  "test_index01" : {
    "aliases" : { },
    "mappings" : { },
    "settings" : {
      "index" : {
        "creation_date" : "1678969193239",
        "number_of_shards" : "1",
        "number_of_replicas" : "1",
        "uuid" : "n6tD0dyxTB2aOQjqyDK0QQ",
        "version" : {
          "created" : "7060199"
        },
        "provided_name" : "test_index01"
      }
    }
  }
}

4.删除索引

DELETE /test_index01

5.添加文档

格式: PUT /索引名称/类型/id

PUT /test_index01/_doc/1
{
"name": "张三",
"sex": 1,
"age": 25,
"address": "北京",
"remark": "java"
}

执行结果
_index:索引名称
_type：类型
_id：id
_version：版本（因为这条数据可能会被修改，所以版本可能不是1）
result:结果(操作结果，创建，更新等)

{
  "_index" : "test_index01",
  "_type" : "_doc",
  "_id" : "1",
  "_version" : 1,
  "result" : "created",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 0,
  "_primary_term" : 1
}

6.查询索引库

查询格式：GET /索引名称/类型/id

GET /test_index01/_doc/1

查询结果

{
  "_index" : "test_index01",
  "_type" : "_doc",
  "_id" : "1",
  "_version" : 1,
  "_seq_no" : 0,
  "_primary_term" : 1,
  "found" : true,
  "_source" : {
    "name" : "张三",
    "sex" : 1,
    "age" : 25,
    "address" : "北京",
    "remark" : "java"
  }
}

6.1查询索引库中所有内容

格式: GET /索引名称/类型/_search

GET /test_index01/_doc/_search

相当于mysql中的 select *
结果（我这里只有一条数据）

#! Deprecation: [types removal] Specifying types in search requests is deprecated.
{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "test_index01",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "name" : "秀儿",
          "sex" : 1,
          "age" : 25,
          "address" : "上海",
          "remark" : "java"
        }
      }
    ]
  }
}

6.2简单等值查询

格式: GET /索引名称/类型/_search?q=:**

GET /test_index01/_doc/_search?q=age:25

6.3简单范围查询

格式: GET /索引名称/类型/_search?q=***[left TO tight]

GET /test_index01/_doc/_search?q=age[25 TO 26]

6.4 通过id进行in查询

格式: GET /索引名称/类型/_mget

GET /test_index01/_doc/_mget
{
"ids":["1","2"]
}

6.5分页查询

GET /索引名称/类型/_search?from=0&size=1
GET /索引名称/类型/_search?q=条件&from=0&size=1

GET /test_index01/_doc/_search?from=0&size=1

GET /test_index01/_doc/_search?q=age[25 TO 26]&from=0&size=1

6.6对查询结果只显示指定字段

GET /索引名称/类型/_search?_source=字段,字段

GET /test_index01/_doc/_search?_source=name,age

6.7排序查询

GET /索引名称/类型/_search?sort=字段 desc

GET /test_index01/_doc/_search?sort=age:desc
GET /test_index01/_doc/_search?sort=age:asc

7.修改索引内容

格式：PUT /索引名称/类型/id

PUT /test_index01/_doc/1
{
"name": "秀儿",
"sex": 1,
"age": 25,
"address": "上海",
"remark": "java"
}

结果

{
  "_index" : "test_index01",
  "_type" : "_doc",
  "_id" : "1",
  "_version" : 2,
  "result" : "updated",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 1,
  "_primary_term" : 1
}

8.删除索引内容

格式: DELETE /索引名称/类型/id

DELETE /test_index01/_doc/1

结果

{
  "_index" : "test_index01",
  "_type" : "_doc",
  "_id" : "1",
  "_version" : 3,
  "result" : "deleted",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 2,
  "_primary_term" : 1
}

9.PUT和POST区别

post和put都能实现创建和更新操作
①PUT:
(1)需要对一个具体的资源进行操作，所以必须要有id才能更新和创建操作。没有就会执行失败
(2)只会将json数据全都进行替换
(3)与delete都是幂等操作，无论操作多少次结果都一样
②POST:
(1)针对整个资源集合进行操作，如果不写id就会由es生成一个唯一的id进行创建文档，如果指定id则会对应创建或者更新文档。
(2)只会更新相同字段的值