ElasticSearch多種搜尋方式
1、query string search
2、query DSL
3、queryfilter
4、full-tex search
5、phrase search
6、highlight search

1、query string search
搜尋全部資訊

格式：GET /index/type/_search

GET /employee/user/_search

took:耗時幾毫秒 timed_out:是否超時，這裡是沒有
_shareds:資料拆分了5個分片，所以對於搜尋請求，會打到所有的primary shard(或者是它的某個replica shard也可以) hits.total:查詢結果的數量，2表示document
hits.max_score:score的含義，就是document對於一個search相關度的匹配分數，越相關，就越匹配，分數也高
hits.hits:包含了匹配搜尋的document的詳細資料

結果:

{
  "took": 2,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 2,
    "max_score": 1,
    "hits": [
      {
        "_index": "employee",
        "_type": "user",
        "_id": "2",
        "_score": 1,
        "_source": {
          "name": "lisi",
          "sez": "M",
          "china": 90,
          "addr": "beijing",
          "join": [
            "chengdu",
            "shenzhen",
            "wuhan"
          ]
        }
      },
      {
        "_index": "employee",
        "_type": "user",
        "_id": "3",
        "_score": 1,
        "_source": {
          "name": "wangwu",
          "sez": "M",
          "china": 60,
          "addr": "xian",
          "join": [
            "xiamen",
            "nanning",
            "changsha"
          ]
        }
      }
    ]
  }
}
 

這個查詢還可以帶上一些引數，例如，搜尋名字是"lisi"的人，而且按照語文成績降序排序

GET /employee/user/_search?q=name:lisi&sort=china:desc

這種操作在生產使用比較少，因為複雜的查詢很難去構建請求

2、query DSL
DSL：Domain Specified Language，特定領域的語言
http request body：請求體，可以用json的格式來構建查詢語法，比較方便，可以構建各種複雜的語法

查詢所有的同學

GET /employee/user/_search
{
  "query": {
    "match_all": {}
  }
}
 

結果

{
  "took": 91,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 3,
    "max_score": 1,
   ........
        }
      }
    ]
  }
}

查詢名字包含lisi的同學，同時按照語文成績降序排序

GET /employee/user/_search
{
  "query": {
    "match": {
      "name": "lisi"
    }
  },
  "sort": [
    {
      "china": {
        "order": "desc"
      }
    }
  ]
}

分頁查詢同學，總共3個同學，假設每頁就顯示1條同學，現在顯示第2頁，所以就查出來第2個同學

GET /employee/user/_search
{
  "query": {
    "match_all": {}
  },
  "from": 1
  , "size": 1
}

指定要查詢指定同學名稱和成績就可以

GET /employee/user/_search
{
  "query": {"match_all": {}},
  "_source": ["name","china"]
}

3、query filter
對資料進行過濾
查詢所有學生中名字是lisi的，成績大於60的記錄

must是必須匹配的

GET /employee/user/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "name": "lisi"
          }
        }
      ],
      "filter": {
        "range": {
          "china": {
            "gt": 60
          }
        }
      }
    }
  }
}

4、full-text search（全文檢索）
先構建倒排索引，在用查詢的值拆詞以後去匹配，score表示相似度，值越大，相似度越高

GET /employee/user/_search
{
  "query": {
    "match": {
      "join": "shenzhen beijing"
    }
  }
}

結果

{
  "took": 8,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 2,
    "max_score": 0.5753642,
    "hits": [
      {
        "_index": "employee",
        "_type": "user",
        "_id": "5",
        "_score": 0.5753642,
        "_source": {
          "name": "lisi",
          "sez": "F",
          "china": 60,
          "addr": "beijing",
          "join": [
            "chengdu",
            "shenzhen",
            "beijing"
          ]
        }
      },
      {
        "_index": "employee",
        "_type": "user",
        "_id": "3",
        "_score": 0.2876821,
        "_source": {
          "name": "lisi",
          "sez": "F",
          "china": 70,
          "addr": "beijing",
          "join": [
            "chengdu",
            "shenzhen",
            "wuhan"
          ]
        }
      }
    ]
  }
}

5、phrase search（短語搜尋）

跟全文檢索相對應，相反，全文檢索會將輸入的搜尋串拆解開來，去倒排索引裡面去一一匹配，只要能匹配上任意一個拆解後的單詞，就可以作為結果返回
phrase search，要求輸入的搜尋串，必須在指定的欄位文字中，完全包含一模一樣的，才可以算匹配，才能作為結果返回

GET /ecommerce/product/_search
{
    "query" : {
        "match_phrase" : {
            "producer" : "yagao producer"
        }
    }
}

6、highlight search（高亮搜尋結果）

GET /employee/user/_search
{
  "query": {
    "match": {
      "name": "lisi"
    }
  },
  "highlight": {
    "fields": {
      "name": {}
    }
  }
}