有用的链接：
ES 可视化工具
基本概念：
Homebrew 安装 Elasticsearch
安装
启动
- Elasticsearch-head 解决跨域问题
- ES term 和 match 的区别

有用的链接：

https://docs.es.shiyueshuyi.xyz/#/intro/datain
https://www.cnblogs.com/cjsblog/p/9439331.html
https://www.cnblogs.com/niceyoo/p/12936325.html
ElasticSearch 搜索报错问题 No mapping found for [column] in order to sort on:
https://blog.csdn.net/caojianwei1992/article/details/88971733
ElasticSearch 官方文档：
https://www.elastic.co/guide/en/elasticsearch/reference/current/index.html

ES 可视化工具

https://cloud.tencent.com/developer/article/1638819

基本概念：

Elasticsearch是一个高度可伸缩的开源全文搜索和分析引擎，RestFul 风格。提供查询，聚合等功能。
Near RealTime (NRT) ElasitcSearch 是一个近乎实时的搜索平台，倒排索引。
Node: 一个ElasticSearch 实例被称作一个Node，一个服务器上可以有多个ES 实例。多个实例共同构成一个集群。
Index：索引，数据库。
Document：被索引的文档，用JSON表示。
索引可以被分片也可以被复制。
Homebrew 安装 Elasticsearch
基本命令： ```bash
安装
brew tap elastic/tap brew install elasticsearch-full

启动

brew services start elasticsearch-full

Homebrew 安装 Elasticsearch的路径如下 （同理，kibana, filebeat, logstash ）：<br />![截屏2022-01-03 上午1.33.15.png](https://cdn.nlark.com/yuque/0/2022/png/22970599/1641144810892-19446494-4cb8-46d0-9c97-3b7aa076b46a.png#clientId=u79d4c732-bfc3-4&from=drop&id=uca23dce4&margin=%5Bobject%20Object%5D&name=%E6%88%AA%E5%B1%8F2022-01-03%20%E4%B8%8A%E5%8D%881.33.15.png&originHeight=784&originWidth=1564&originalType=binary&ratio=1&size=183703&status=done&style=none&taskId=u1200a3f7-e265-40f5-922a-4c2909974f3)
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## 基本操作
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### 增删查改
1. 集群健康
```json
curl -X GET "localhost:9200/_cat/health?v"

集群节点

curl -X GET "localhost:9200/_cat/nodes?v"

集群索引

curl -X GET "localhost:9200/_cat/indices?v"

创建索引

curl -X PUT "localhost:9200/{index_name}?pretty"

创建索引并添加数据

curl -X PUT "localhost:9200/{index_name}/{type}/{id}?pretty" -H 'Content-Type: application/json' -d'{"name": "John Doe"}'

删除索引

curl -X DELETE "localhost:9200/{index_name}?pretty"

修改数据（POST 用于更新文档，PUT 用于添加数据）

curl -X POST "localhost:9200/customer/_doc/1/_update?pretty" -H 'Content-Type: application/json' -d'
{
"doc": { "name": "Jane Doe", "age": 20 }
}
'

注意文档要是JSON格式，且前面一定要加上 “doc” 字段

脚本

curl -X POST "localhost:9200/customer/_doc/1/_update?pretty" -H 'Content-Type: application/json' -d'
{
"script" : "ctx._source.age += 5"
}
'

删除文档

curl -X DELETE "localhost:9200/{index_name}/{type}/{doc_id}?pretty"

批处理 (使用bulk API)

curl -X POST "localhost:9200/{index_name}/{type}/_bulk?pretty" -H 'Content-Type: application/json' -d'
{"index":{"_id":"1"}}
{"name": "John Doe" }
{"index":{"_id":"2"}}
{"name": "Jane Doe" }
'

注意一定要申明 {“index” : {“_id” : “num”}}, 否则ES不知道该更新哪个文档

加载JSON 数据

curl -H "Content-Type: application/json" -XPOST "localhost:9200/{index_name}/{type}/_bulk?pretty&refresh" --data-binary "@/path/accounts.json"

查询+sort 排序

curl -X GET "localhost:9200/{index_name}/_search" -H 'Content-Type: application/json' -d'
{
"query": { "match_all": {} },
"sort": [
{ "account_number": "asc"/"des"}
]
}
'

match 指定数量的文档

curl -X GET "localhost:9200/{index_name}/_search" -H 'Content-Type: application/json' -d'
{
"query": { "match_all": {} },
"from": 10,
"size": 10
}
'

搜索指定字段

相当于SELECT account_number， balance FROM bank

curl -X GET "localhost:9200/bank/_search" -H 'Content-Type: application/json' -d'
{
  "query": { "match_all": {} },
  "_source": ["account_number", "balance"]
}
'

匹配指定字段

curl -X GET "localhost:9200/bank/_search" -H 'Content-Type: application/json' -d'
{
"query": { "match": { "account_number": 20 } }
}
'

curl -X GET "localhost:9200/bank/_search" -H 'Content-Type: application/json' -d'
{
"query": { "match": { "address": "mill lane" } }
}
'

相当于SELECT * FROM bank WHERE address LIKE ‘%mill’ OR address LIKE ‘%lane%’
mill 或者 lane 只要又一个匹配就会返回结果

组合查询 (用“bool” 来组合多个查询条件) ```json curl -X GET “localhost:9200/bank/_search” -H ‘Content-Type: application/json’ -d’ { “query”: { “bool”: { “must”: [
```
{ "match": { "address": "mill" } },
{ "match": { "address": "lane" } }
```
] } } } ‘

curl -X GET “localhost:9200/bank/_search” -H ‘Content-Type: application/json’ -d’ { “query”: { “bool”: { “must”: [ { “match”: { “age”: “40” } } ], “must_not”: [ { “match”: { “state”: “ID” } } ] } } } ‘

curl -X GET “localhost:9200/bank/_search” -H ‘Content-Type: application/json’ -d’ { “query”: { “bool”: { “should”: [ { “match”: { “address”: “mill” } }, { “match”: { “address”: “lane” } } ] } } } ‘

must 相当于 and， should 相当于 or

17.  过滤器和range 使用:
```json
curl -X GET "localhost:9200/bank/_search" -H 'Content-Type: application/json' -d'
{
  "query": {
    "bool": {
      "must": { "match_all": {} },
      "filter": {
        "range": {
          "balance": {
            "gte": 20000,
            "lte": 30000
          }
        }
      }
    }
  }
}
'

聚集，相当于 SQL 里的聚集函数，例如分组，求和，求平均之类。

terms 指定聚集的字段

curl -X GET "localhost:9200/{index_name}/_search" -H 'Content-Type: application/json' -d'
{
  "size": 0,
  "aggs": {
    "group_by_state": {
      "terms": {
        "field": "state.keyword"
      }
    }
  }
}
'

先聚集，然后组内求平均 (avg 函数), 嵌套聚合

curl -X GET "localhost:9200/bank/_search" -H 'Content-Type: application/json' -d'
{
"size": 0,
"aggs": {
"group_by_state": {
  "terms": {
    "field": "state.keyword"
  },
  "aggs": {
    "average_balance": {
      "avg": {
        "field": "balance"
      }
    }
  }
}
}
}
'

按年龄段分组，组内按性别分组，性别组再求平均（field, rangs, terms, aggs, avg 函数）

curl -X GET "localhost:9200/bank/_search" -H 'Content-Type: application/json' -d'
{
"size": 0,
"aggs": {
"group_by_age": {
  "range": {
    "field": "age",
    "ranges": [
      {
        "from": 20,
        "to": 30
      },
      {
        "from": 30,
        "to": 40
      },
      {
        "from": 40,
        "to": 50
      }
    ]
  },
  "aggs": {
    "group_by_gender": {
      "terms": {
        "field": "gender.keyword"
      },
      "aggs": {
        "average_balance": {
          "avg": {
            "field": "balance"
          }
        }
      }
    }
  }
}
}
}
'

Elasticsearch-head 解决跨域问题

进入目录：cd /usr/local/etc/elasticsearch/
修改yml文件：open -e elasticsearch.yml

ES term 和 match 的区别

term 是精准匹配，在搜索前不会对搜索次进行分词处理。如果要匹配多个次可以使用
terms : {title : [‘term 1’, ‘term 2’]} 两个term 之间是or的关系
match 是模糊匹配，
https://www.jianshu.com/p/d5583dff4157

Java 生态学习笔记

ElasticSearch 学习笔记

有用的链接：

ES 可视化工具

基本概念：

Homebrew 安装 Elasticsearch

安装

启动

Elasticsearch-head 解决跨域问题

ES term 和 match 的区别