Elasticsearch黑鸟教程26：Elasticsearch搜索数据基本操作

1、Elasticsearch搜索方式介绍

Elasticsearch官方提供了两中检索方式：一种是通过 URL 参数进行搜索，另一种是通过 DSL(Domain Specified Language) 进行搜索。官方更推荐使用第二种方式， 第二种方式是基于传递JSON作为请求体(request body)格式与Elasticsearch进行交互，这种方式更强大，更简洁。

备注：DSL是什么？请移步：http://www.mybatis.cn/archives/1229.html

2、Elasticsearch搜索数据实战操作：采用URL参数的形式

首先，准备测试数据：

curl -X PUT -H 'Content-Type: application/json' 'localhost:9200/myindex' -d '
{
    "settings": {
        "number_of_shards": 1,
        "number_of_replicas": 0
    }
}
'

curl -X PUT "localhost:9200/myindex/_doc/1?pretty" -H 'Content-Type: application/json' -d'{
    "id":1,
    "title":"网站公告1",
    "content":"大家注意了，网站核心社群正式启动!",
    "date":"2020-05-12"
}'

curl -X PUT "localhost:9200/myindex/_doc/2?pretty" -H 'Content-Type: application/json' -d'{
    "id":2,
    "title":"网站公告2",
    "content":"各位读者，大家好：祝大家元旦快乐！",
    "date":"2021-01-01"
}'

执行搜索操作：

[root@root ~]# curl -X GET -H 'Content-Type: application/json'  "localhost:9200/myindex/_search?q=*&sort=date:asc&pretty"

{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [
      {
        "_index" : "myindex",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : null,
        "_source" : {
          "id" : 1,
          "title" : "网站公告1",
          "content" : "大家注意了，网站核心社群正式启动!",
          "date" : "2020-05-12"
        },
        "sort" : [
          1589241600000
        ]
      },
      {
        "_index" : "myindex",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : null,
        "_source" : {
          "id" : 2,
          "title" : "网站公告2",
          "content" : "各位读者，大家好：祝大家元旦快乐！",
          "date" : "2021-01-01"
        },
        "sort" : [
          1609459200000
        ]
      }
    ]
  }
}

3、Elasticsearch搜索数据实战操作：采用DSL方式

[root@root ~]# curl -X POST -H 'Content-Type: application/json'  "localhost:9200/myindex/_search?pretty" -d '{
     "query": {"match_all": {}},
     "sort": [
         {
             "date": {
                 "order": "asc"
             }
         }
     ]
 }'

{
  "took" : 2,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [
      {
        "_index" : "myindex",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : null,
        "_source" : {
          "id" : 1,
          "title" : "网站公告1",
          "content" : "大家注意了，网站核心社群正式启动!",
          "date" : "2020-05-12"
        },
        "sort" : [
          1589241600000
        ]
      },
      {
        "_index" : "myindex",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : null,
        "_source" : {
          "id" : 2,
          "title" : "网站公告2",
          "content" : "各位读者，大家好：祝大家元旦快乐！",
          "date" : "2021-01-01"
        },
        "sort" : [
          1609459200000
        ]
      }
    ]
  }
}