Elasticsearch(一)

ES安装

https://www.elastic.co/cn/downloads/elasticsearch
1.下载好对应的文件压缩包
2.解压以后 在bin目录下打开elasticsearch.bat 即可启动（注意：启动es会吃很多内存，内存不够需要修改就找到config文件目录下的jvm.options，打开找到（Xms：代表最小2G，Xmx代表最大2G），修改最小为200m，运行内存会变小。）
3.验证：访问：http://localhost:9200 默认端口

org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root
	at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:163) ~[elasticsearch-7.3.2.jar:7.3.2]
	at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:150) ~[elasticsearch-7.3.2.jar:7.3.2]
	at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86) ~[elasticsearch-7.3.2.jar:7.3.2]
	at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124) ~[elasticsearch-cli-7.3.2.jar:7.3.2]
	at org.elasticsearch.cli.Command.main(Command.java:90) ~[elasticsearch-cli-7.3.2.jar:7.3.2]
	at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:115) ~[elasticsearch-7.3.2.jar:7.3.2]
	at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:92) ~[elasticsearch-7.3.2.jar:7.3.2]
Caused by: java.lang.RuntimeException: can not run elasticsearch as root
	at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:105) ~[elasticsearch-7.3.2.jar:7.3.2]
	at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:172) ~[elasticsearch-7.3.2.jar:7.3.2]
	at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:349) ~[elasticsearch-7.3.2.jar:7.3.2]
	at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:159) ~[elasticsearch-7.3.2.jar:7.3.2]
	... 6 more
报这个错误说明不能以root用户启动

启动成功后，使用浏览器或者curl命令可以看到如下信息

{
  "name" : "localhost.localdomain",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "SimUAqM4SqyzMWRd7nJQhQ",
  "version" : {
    "number" : "7.3.2",
    "build_flavor" : "default",
    "build_type" : "tar",
    "build_hash" : "1c1faf1",
    "build_date" : "2019-09-06T14:40:30.409026Z",
    "build_snapshot" : false,
    "lucene_version" : "8.1.0",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },
  "tagline" : "You Know, for Search"
}

elasticsearch配置

属性名	说明
cluster.name	配置elasticsearch的集群名称，默认是elasticsearch。建议修改成一个有意义的名称。
node.name	节点名，es会默认随机指定一个名字，建议指定一个有意义的名称，方便管理
path.conf	设置配置文件的存储路径，tar或zip包安装默认在es根目录下的config文件夹，rpm安装默认在/etc/ elasticsearch
path.data	设置索引数据的存储路径，默认是es根目录下的data文件夹，可以设置多个存储路径，用逗号隔开
path.logs	设置日志文件的存储路径，默认是es根目录下的logs文件夹
path.plugins	设置插件的存放路径，默认是es根目录下的plugins文件夹
bootstrap.memory_lock	设置为true可以锁住ES使用的内存，避免内存进行swap
network.host	设置bind_host和publish_host，设置为0.0.0.0允许外网访问
http.port	设置对外服务的http端口，默认为9200。
transport.tcp.port	集群结点之间通信端口
discovery.zen.ping.timeout	设置ES自动发现节点连接超时的时间，默认为3秒，如果网络延迟高可设置大些
discovery.zen.minimum_master_nodes	主结点数量的最少值 ,此值的公式为：(master_eligible_nodes / 2) + 1 ，比如：有3个符合要求的主结点，那么这里要设置为2

---

建议：9300：集群节点间通讯接口
9200：客户端访问接口

---

使用入门

本质上也是储存数据 所以许多概念与Mysql类似
索引（indices）---------------数据库

文档（Document）------------Row 行

字段（Field）-------------------Columns 列

属性名	说明
索引库（indices)	indices是index的复数，代表许多的索引，
文档（document）	存入索引库原始的数据。比如每一条商品信息，就是一个文档
字段（field）	文档中的属性
映射配置（mappings）	字段的数据类型、属性、是否索引、是否存储等特性

---

要注意的是：Elasticsearch本身就是分布式的，因此即便你只有一个节点，Elasticsearch默认也会对你的数据进行分片和副本操作，当你向集群添加新数据时，数据也会在新加入的节点中进行平衡。

---

创建索引库（数据库）

"number_of_shards": 1 分片数
"number_of_replicas": 1 副本数

PUT people
{
  "settings": {
    "number_of_shards": 1,
    "number_of_replicas": 1
  }

}

返回结果

{
  "acknowledged" : true,
  "shards_acknowledged" : true,
  "index" : "people"
}

删索引库

GET  people

结果：

{
  "people" : {
    "aliases" : { },
    "mappings" : { },
    "settings" : {
      "index" : {
        "creation_date" : "1564308107803",
        "number_of_shards" : "1",
        "number_of_replicas" : "1",
        "uuid" : "zQYt9-BXR9yuQOLNugAabg",
        "version" : {
          "created" : "7020099"
        },
        "provided_name" : "item"
      }
    }
  }
}

查询索引库是否存在

HEAD people

返回

200 - OK

创建映射关系(数据库列)

• type：类型，可以是text、long、short、date、integer、object等
• index：是否索引，默认为true
• store：是否存储，默认为false
• analyzer：分词器，这里的ik_max_word即使用ik分词器

PUT people/_mapping
{
  "properties": {
    "name": {
      "type": "text",
      "analyzer": "ik_max_word"
    },
    "age": {
      "type": "integer",
      "index": "false"
    },
    "sex": {
      "type": "keyword"
    }
  }
}

如果再次创建不通话映射则为新增映射

查询映射关系

GET people/_mapping

返回结果

{
  "people" : {
    "mappings" : {
      "properties" : {
        "age" : {
          "type" : "integer",
          "index" : false
        },
        "name" : {
          "type" : "text",
          "analyzer" : "ik_max_word"
        },
        "sex" : {
          "type" : "keyword"
        }
      }
    }
  }
}

添加 更新数据

我们也可以直接添加数据 这样系统会给我们默认生成一套映射关系
如果_doc 后面不指定id数 会默认生成随机id

POST people/_doc/1
{
  "name" : "小明",
  "age" : 18,
  "sex": "男"
}

使用相同的代码更改部分 即可更改

POST people/_doc/1
{
  "name" : "小红",
  "age" : 18,
  "sex": "女"
}

通过查询获取id 然后更新即可

获取数据

GET people/_doc/1

或者查询所有

GET people/_search

{
  "_index" : "people",
  "_type" : "_doc",
  "_id" : "1",
  "_version" : 3,
  "_seq_no" : 2,
  "_primary_term" : 1,
  "found" : true,
  "_source" : {
    "name" : "小红",
    "age" : 18,
    "sex" : "女"
  }
}

删除数据

通过查询id进行删除即可

DELETE people/_doc/1

查询功能

我们添加小王2 和小男

POST people/_doc/2
{
  "name" : "小王2",
  "age" : 22,
  "sex": "男"
}

POST people/_doc/3
{
  "name" : "小男",
  "age" : 22,
  "sex": "男"
}

全部查询

基本语法

GET /索引库名/_search
{
    "query":{
        "查询类型":{
            "查询条件":"查询条件值"
        }
    }
}

返回结果

time_out：是否超时
_shards：分片信息
hits：搜索结果总览对象
total：搜索到的总条数
max_score：所有结果中文档得分的最高分
hits：搜索结果的文档对象数组，每个元素是一条搜索到的文档信息
_index：索引库
_type：文档类型
_id：文档id
_score：文档得分
_source：文档的源数据

---

默认查询所有的people下的数据

GET people/_search

返回结果

{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "people",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "name" : "小红",
          "age" : 18,
          "sex" : "女"
        }
      },
      {
        "_index" : "people",
        "_type" : "_doc",
        "_id" : "-idVPGwBetwbYuu2n6UB",
        "_score" : 1.0,
        "_source" : {
          "name" : "小王",
          "age" : 22,
          "sex" : "男"
        }
      }
    ]
  }
}

查询所有的people下的数据

GET people/_search
{
  "query": {
    "match_all": {}
  }
}

匹配查询

查询name是小王2的字段 默认情况为or （即包含小王字段的也会查询到）

GET people/_search
{
  "query": {
    "match": {
      "name": "小王2"
    }
  }
}

返回结果(部分)

  "hits" : [
      {
        "_index" : "people",
        "_type" : "_doc",
        "_id" : "-idVPGwBetwbYuu2n6UB",
        "_score" : 0.52354836,
        "_source" : {
          "name" : "小王",
          "age" : 22,
          "sex" : "男"
        }
      },
      {
        "_index" : "people",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 0.39019167,
        "_source" : {
          "name" : "小王2",
          "age" : 22,
          "sex" : "男"
        }
      }
    ]

如果我们只想要小王2 则通过更改关联关系(此时我们只能查询到小王2)

GET people/_search
{
  "query": {
    "match": {
      "name":{"query": "小王2","operator": "and"}
    }
  }
}

设置最小匹配度查询

如果满足其中的50% 岂可视为查询正确 小王和小王2都会查询出来
如果设置为100% 则只会查出小王2

GET people/_search
{
  "query": {
    "match": {
      "name":{"query": "小王2","minimum_should_match": "50%"}
    }
  }
}

多字段查询

我们在sex 和name中查询带 “男”字 的信息

GET people/_search
{
  "query": {
    "multi_match": {
      "query": "男"
      , "fields": ["name","sex"]
    }
  }
}

返回结果

"hits" : [
      {
        "_index" : "people",
        "_type" : "_doc",
        "_id" : "-idVPGwBetwbYuu2n6UB",
        "_score" : 0.2876821,
        "_source" : {
          "name" : "小王",
          "age" : 22,
          "sex" : "男"
        }
      },
      {
        "_index" : "people",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 0.2876821,
        "_source" : {
          "name" : "小王2",
          "age" : 22,
          "sex" : "男"
        }
      },
      {
        "_index" : "people",
        "_type" : "_doc",
        "_id" : "3",
        "_score" : 0.2876821,
        "_source" : {
          "name" : "小男",
          "age" : 22,
          "sex" : "男"
        }
      }
    ]

词条匹配（精确查找）

term 查询被用于精确值 匹配，这些精确值可能是数字、时间、布尔或者那些未分词的字符串
terms 就是查询多个

GET people/_search
{
 "query": {
   "terms": {
     "sex": [
       "男","女"
     ]
   }
 }

结果(部分)

"hits" : [
    {
      "_index" : "people",
      "_type" : "_doc",
      "_id" : "1",
      "_score" : 1.0,
      "_source" : {
        "name" : "小红",
        "age" : 18,
        "sex" : "女"
      }
    },
    {
      "_index" : "people",
      "_type" : "_doc",
      "_id" : "-idVPGwBetwbYuu2n6UB",
      "_score" : 1.0,
      "_source" : {
        "name" : "小王",
        "age" : 22,
        "sex" : "男"
      }
    },
    {
      "_index" : "people",
      "_type" : "_doc",
      "_id" : "2",
      "_score" : 1.0,
      "_source" : {
        "name" : "小王2",
        "age" : 22,
        "sex" : "男"
      }
    },
    {
      "_index" : "people",
      "_type" : "_doc",
      "_id" : "3",
      "_score" : 1.0,
      "_source" : {
        "name" : "小男",
        "age" : 22,
        "sex" : "男"
      }
    }
  ]

结果过滤
我们只需要name字段

GET people/_search
 {
   
   "query": {
     "terms": {
       "sex": [
         "男","女"
       ]
     }
   },"_source": "name"
 }

我们不需要带有age 的信息

GET people/_search
 {
   
   "query": {
     "terms": {
       "sex": [
         "男","女"
       ]
     }
   },"_source": {
     "excludes": "age"
   }
 }

我们只需要性别和名字

  GET people/_search
  {
    
    "query": {
      "terms": {
        "sex": [
          "男","女"
        ]
      }
    },"_source": {
      "includes": ["name","sex"]
    }
  }

返回结果(部分)

 "hits" : [
      {
        "_index" : "people",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "sex" : "女",
          "name" : "小红"
        }
      },
      {
        "_index" : "people",
        "_type" : "_doc",
        "_id" : "-idVPGwBetwbYuu2n6UB",
        "_score" : 1.0,
        "_source" : {
          "sex" : "男",
          "name" : "小王"
        }
      },
      {
        "_index" : "people",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "sex" : "男",
          "name" : "小王2"
        }
      },
      {
        "_index" : "people",
        "_type" : "_doc",
        "_id" : "3",
        "_score" : 1.0,
        "_source" : {
          "sex" : "男",
          "name" : "小男"
        }
      }
    ]
    ```