Elasticsearch7.x常用API

注意：在 ES 7.X 之后 删除了映射类型

参见 ES 官方说明：https://www.elastic.co/guide/en/elasticsearch/reference/7.x/removal-of-types.html

一般碰到报错:”Types cannot be provided in put mapping requests, unless the include_type_name parameter is set to true”
，都是因为 ElasticSearch 从低版本升级到高版本造成的

新的 ElasticSearch 7.x，做了调整，要求 mapping 时不需要提交 type，为了确保旧代码的兼容性，加入了一个include_type_name
的参数，而这样的请求，Head 插件自带的请求时无法完成的这时候我么就需要借助 postman 工具。

创建索引和设置 Mapping 一步完成

创建文档

这一切都可以在 Head 的可视化界面中得到验证

GET /ssns-message-202104/_search

{
  "size": 0,
  "query": {
    "terms": {
      "chatroomId": [
        "4596907111",
        "5860373121",
        "5860373121"
      ]
    }
  },
  "aggs": {
    "agg_chatroomId": {
      "terms": {
        "field": "chatroomId"
      }
    }
  }
}

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 3,
    "successful": 3,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 16829,
    "max_score": 0,
    "hits": []
  },
  "aggregations": {
    "agg_chatroomId": {
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0,
      "buckets": [
        {
          "key": "5860373121",
          "doc_count": 13999
        },
        {
          "key": "4596907111",
          "doc_count": 2830
        }
      ]
    }
  }
}

相当于 MySQL 中的语句如下

select count(1) from ssns-message-202104 where chatroomId in ('4596907111','5860373121','5860373121') group by chatroomId

只查询文档中的_id 和 memberList 字段
GET xxxx/room/_search

{
  "_source": [
    "_id",
    "memberList"
  ],
  "query": {
    "term": {
      "departments.tree": {
        "value": "/xx/xx"
      }
    }
  }
}

查找 uin 字段中包含@chatroom 字符串的数据
GET xxx/account/_search

{
  "query": {
    "bool": {
      "must": [
        {
          "regexp": {
            "uin": {
              "value": ".*@chatroom.*"
            }
          }
        }
      ]
    }
  }
}

先按照创建时间字段降序，再按照打分降序
GET xxx/account/_search

{
  "query": {},
  "sort": [
    {
      "createTime": {
        "order": "desc"
      }
    },
    {
      "_score": {
        "order": "desc"
      }
    }
  ]
}

查找存在 uin 字段的数据
GET xxx/account/_search

{
  "query": {
    "bool": {
      "filter": [
        {
          "exists": {
            "field": "uin"
          }
        }
      ]
    }
  }
}

分页查询数据，相当于数据库中的 limit 关键字的用法，from 默认是 0，size 默认是 20
GET xxx/account/_search

{
  "from": 0,
  "size": 20
}

假如页大小是 pageSize，页号为 pageNum
from=(pageNum-1)*pageSize
size=pageSize
例如：如果页大小是 20，要查询第三页的数据，那么 from 为(3-1)*`20=60，size 为 20

{
  "query": {
    "bool": {
      "filter": [
        {
          "script": {
            "script": {
              "source": "doc['rooms'].length >= 1",
              "lang": "painless"
            }
          }
        }
      ]
    }
  }
}

{
  "query": {},
  "sort": [
    {
      "_script": {
        "script": {
          "inline": "doc['rooms'].values.size()"
        },
        "type": "number",
        "order": "desc"
      }
    }
  ]
}

script script = new script("doc['rooms'].values.size()");
scriptSortBuilder sortBuilder = SortBuilders.scriptSort(script, scriptSortBuilder.scriptSortType.NUMBER).order(SortOrder.DESC);