大数据学习（35）—— ElasticSearch实验

安装ElasticSearch

在安装ES之前，需要安装JDK。

从官网下载ES8.1压缩包，在服务器上解压，只部署一个节点用来演示。

[es@localhost home]$ ls -ltr
总用量 767132
-rw-r--r--.  1 root root 515805548 3月  21 11:40 elasticsearch-8.1.0-linux-x86_64.tar.gz
drwxr-xr-x. 10 es   es         167 3月  21 12:57 elasticsearch-8.1.0

修改elasticsearch-8.1.0/config/elasticsearch.yml，这几个配置需要修改一下。

network.host: 192.168.0.31
http.port: 9200

xpack.security.enabled: false

http.host: 0.0.0.0
discovery.seed_hosts: ["0.0.0.0","[::1]"]

ingest.geoip.downloader.enabled: false

切换目录到elasticsearch-8.1.0/bin，启动ElasticSearch。

[es@localhost bin]$ sh elasticsearch -d

启动完成后，查看ES状态。

[es@localhost bin]$ curl -X GET 'localhost:9200/_cluster/health?pretty'
{
"cluster_name" : "elasticsearch",
"status" : "green",
"timed_out" : false,
"number_of_nodes" : 1,
"number_of_data_nodes" : 1,
"active_primary_shards" : 10,
"active_shards" : 10,
"relocating_shards" : 0,
"initializing_shards" : 0,
"unassigned_shards" : 0,
"delayed_unassigned_shards" : 0,
"number_of_pending_tasks" : 0,
"number_of_in_flight_fetch" : 0,
"task_max_waiting_in_queue_millis" : 0,
"active_shards_percent_as_number" : 100.0
}

curl操作ES

创建索引

[es@localhost bin]$ curl -X PUT "localhost:9200/db3?pretty"
{
  "acknowledged" : true,
  "shards_acknowledged" : true,
  "index" : "db3"
}

查看索引

@localhost bin]$ curl -X GET 'http://localhost:9200/_cat/indices?v'
health status index uuid                   pri rep docs.count docs.deleted store.size pri.store.size
green  open   db1   eyOyU8sQTaeOGvdAXF1P4A   1   0          0            0       225b           225b
yellow open   db3   2MIskmW5QaStxt7w4qTg_w   1   1          0            0       225b           225b
green  open   db2   ebgp3yDqQqSbDvp-2Yuxtw   1   0          0            0       225b           225b

从索引状态可以看出，刚刚创建的db3状态是yellow。原因是单机不能启动副本，要把副本数设置为0。

[es@localhost bin]$ curl  -X PUT "localhost:9200/db3/_settings" -H 'Content-Type: application/json' -d'
> {
> "index" : {
> "number_of_replicas" : 0
> }
> }
> '

返回：
{"acknowledged":true}

[es@localhost bin]$ 
[es@localhost bin]$ curl -X GET 'http://localhost:9200/_cat/indices?v'
health status index uuid                   pri rep docs.count docs.deleted store.size pri.store.size
green  open   db1   eyOyU8sQTaeOGvdAXF1P4A   1   0          0            0       225b           225b
green  open   db3   2MIskmW5QaStxt7w4qTg_w   1   0          0            0       225b           225b
green  open   db2   ebgp3yDqQqSbDvp-2Yuxtw   1   0          0            0       225b           225b

创建文档

[es@localhost bin]$ curl -H 'Content-Type:application/json' -X POST http://localhost:9200/db3/_doc/1 -d '{
"id": "1",
"name": "ZhangSan",
"age": 17,
"sex": "M"
}'

返回：
{"_index":"db3","_id":"1","_version":1,"result":"created","_shards":{"total":1,"successful":1,"failed":0},"_seq_no":0,"_primary_term":1}

通过ID查看文档

[es@localhost bin]$ curl -X GET localhost:9200/db3/_doc/1?pretty
{
  "_index" : "db3",
  "_id" : "1",
  "_version" : 1,
  "_seq_no" : 0,
  "_primary_term" : 1,
  "found" : true,
  "_source" : {
    "id" : "1",
    "name" : "ZhangSan",
    "age" : 17,
    "sex" : "M"
  }
}

查找索引中所有文档

[es@localhost bin]$ curl -X GET localhost:9200/db3/_search?pretty
{
  "took" : 3,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "db3",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "id" : "1",
          "name" : "ZhangSan",
          "age" : 17,
          "sex" : "M"
        }
      }
    ]
  }
}

match查询

[es@localhost bin]$ curl  -X GET "localhost:9200/db3/_search?pretty" -H 'Content-Type: application/json' -d'
{
 "query" : {
        "match" : {
            "name" : "ZhangSan"
        }
    }
}'

返回：
{
  "took" : 2,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 0.2876821,
    "hits" : [
      {
        "_index" : "db3",
        "_id" : "1",
        "_score" : 0.2876821,
        "_source" : {
          "id" : "1",
          "name" : "ZhangSan",
          "age" : 17,
          "sex" : "M"
        }
      }
    ]
  }
}

filter查询

[es@localhost bin]$ curl  -X GET "localhost:9200/db3/_search?pretty" -H 'Content-Type: application/json' -d'
{
 "query" : {
       "bool": {
            "filter": {
                "range" : {
                    "age" : { "gt" : 15 } 
                }
            }
        }
    }
}'

返回：
{
  "took" : 2,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 0.0,
    "hits" : [
      {
        "_index" : "db3",
        "_id" : "1",
        "_score" : 0.0,
        "_source" : {
          "id" : "1",
          "name" : "ZhangSan",
          "age" : 17,
          "sex" : "M"
        }
      }
    ]
  }
}

更多的语法使用，请参考ElasticSearch:权威指南，这里面有些语法在8.1里已经不支持了。