Query DSL

Elasticsearch 提供了基于 JSON 的完整 Query DSL（Domain Specific Language）來(lái)定義查詢(xún)。
因Query DSL是利用Rest API傳遞JSON格式的請(qǐng)求體(RequestBody)數(shù)據(jù)與ES進(jìn)行交互，所以我們?cè)谑褂胹pringboot的時(shí)候也可以很方便的進(jìn)行集成，本文主要講述的就是使用springboot實(shí)現(xiàn)各類(lèi)DSL的語(yǔ)法查詢(xún)。
Elasticsearch 官網(wǎng)地址

數(shù)據(jù)準(zhǔn)備

新增名為(dsl_index)的索引，并插入部分?jǐn)?shù)據(jù)，本文使用springboot變更Elasticsearch數(shù)據(jù)都是通過(guò)RestHighLevelClient來(lái)操作的

索引(dsl_index)結(jié)構(gòu)：

GET dsl_index/_mappings

{
  "dsl_index" : {
    "mappings" : {
      "properties" : {
        "age" : {
          "type" : "long"
        },
        "description" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "name" : {
          "type" : "text",
          "analyzer" : "ik_max_word",
          "search_analyzer" : "ik_smart"
        }
      }
    }
  }
}

索引(dsl_index)數(shù)據(jù)：

POST /dsl_index/_bulk
{"index":{"_id":1}}
{"name":"張三","age":11,"description":"南京市 羽毛球愛(ài)好者"}
{"index":{"_id":2}}
{"name":"王五","age":15,"description":"北京市 籃球兩年半"}
{"index":{"_id":3}}
{"name":"李四","age":18,"description":"山東省 游泳健身"}
{"index":{"_id":4}}
{"name":"富貴","age":22,"description":"天津市 游泳打球"}
{"index":{"_id":5}}
{"name":"來(lái)福","age":8,"description":"安徽合肥 職業(yè)代練"}
{"index":{"_id":6}}
{"name":"憨憨","age":27,"description":"北京市 健身打球"}
{"index":{"_id":7}}
{"name":"小七","age":31,"description":"北京市 游泳"}

match_all

match_all會(huì)查詢(xún)指定索引下的所有文檔，但是默認(rèn)只會(huì)返回10條數(shù)據(jù)。原因是：_search查詢(xún)默認(rèn)采用的是分頁(yè)查詢(xún)，from=0;size=10 如果想顯示更多數(shù)據(jù)，指定size數(shù)量

DSL: 查詢(xún)當(dāng)前索引下所有數(shù)據(jù)（默認(rèn)前十條）

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

返回?cái)?shù)據(jù)如下:
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 7,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "name" : "張三",
          "age" : 11,
          "description" : "南京市 羽毛球愛(ài)好者"
        }
      },
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "name" : "王五",
          "age" : 15,
          "description" : "北京市 籃球兩年半"
        }
      },
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "3",
        "_score" : 1.0,
        "_source" : {
          "name" : "李四",
          "age" : 18,
          "description" : "山東省 游泳健身"
        }
      },
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "4",
        "_score" : 1.0,
        "_source" : {
          "name" : "富貴",
          "age" : 22,
          "description" : "天津市 游泳打球"
        }
      },
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "5",
        "_score" : 1.0,
        "_source" : {
          "name" : "來(lái)福",
          "age" : 8,
          "description" : "安徽合肥 職業(yè)代練"
        }
      },
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "6",
        "_score" : 1.0,
        "_source" : {
          "name" : "憨憨",
          "age" : 27,
          "description" : "北京市 健身打球"
        }
      },
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "7",
        "_score" : 1.0,
        "_source" : {
          "name" : "小七",
          "age" : 31,
          "description" : "北京市 游泳"
        }
      }
    ]
  }
}

sprongboot實(shí)現(xiàn):

代碼:
    private static final String INDEX_NAME = "dsl_index"; -- 以下統(tǒng)一使用該索引
        
    @Resource
   	private RestHighLevelClient client; -- 以下統(tǒng)一使用該client

    @RequestMapping(value = "/matchAll", method = RequestMethod.GET)
    @ApiOperation(value = "DSL - match_all")
    public void matchAll() throws Exception {
        // 定義請(qǐng)求對(duì)象
        SearchRequest searchRequest = new SearchRequest(INDEX_NAME);
        // 查詢(xún)所有
        searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.matchAllQuery()));
        // 打印返回?cái)?shù)據(jù)
        printLog(client.search(searchRequest, RequestOptions.DEFAULT));
    }

查詢(xún)結(jié)果如下:
		{name=張三, description=南京市 羽毛球愛(ài)好者, age=11}
		{name=王五, description=北京市 籃球兩年半, age=15}
		{name=李四, description=山東省 游泳健身, age=18}
		{name=富貴, description=天津市 游泳打球, age=22}
		{name=來(lái)福, description=安徽合肥 職業(yè)代練, age=8}
		{name=憨憨, description=北京市 健身打球, age=27}
		{name=小七, description=北京市 游泳, age=31}

術(shù)語(yǔ)級(jí)查詢(xún)

官網(wǎng)地址

術(shù)語(yǔ)級(jí)別查詢(xún)（Term-Level Queries）指的是搜索內(nèi)容不經(jīng)過(guò)文本分析直接用于文本匹配，這個(gè)過(guò)程類(lèi)似于數(shù)據(jù)庫(kù)的SQL查詢(xún)，搜索的對(duì)象大多是索引的非text類(lèi)型字段。

Term Query

術(shù)語(yǔ)查詢(xún)直接返回包含搜索內(nèi)容的文檔，常用來(lái)查詢(xún)索引中某個(gè)類(lèi)型為keyword的文本字段，類(lèi)似于SQL的“=”查詢(xún)，因此最好不要在term查詢(xún)的字段中使用text字段，因?yàn)閠ext字段會(huì)被分詞，這樣做既沒(méi)有意義，還很有可能什么也查不到。

DSL: 查詢(xún)當(dāng)前索引下age=31的數(shù)據(jù)

GET dsl_index/_search
{
  "query": {
    "term": {
      "age": {
        "value": "31"
      }
    }
  }
}

返回?cái)?shù)據(jù)如下:
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "7",
        "_score" : 1.0,
        "_source" : {
          "name" : "小七",
          "age" : 31,
          "description" : "北京市 游泳"
        }
      }
    ]
  }
}

springboot實(shí)現(xiàn):

代碼如下:
    @RequestMapping(value = "/term", method = RequestMethod.GET)
    @ApiOperation(value = "DSL - term")
    public void term() throws Exception {
        // 定義請(qǐng)求對(duì)象
        SearchRequest searchRequest = new SearchRequest(INDEX_NAME);
        // 查詢(xún)
        searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.termQuery("age",31)));
        // 打印返回?cái)?shù)據(jù)
        printLog(client.search(searchRequest, RequestOptions.DEFAULT));
    }

查詢(xún)結(jié)果如下:
{name=小七, description=北京市 游泳, age=31}

Terms Query

Terms query用于在指定字段上匹配多個(gè)詞項(xiàng)（terms）。它會(huì)精確匹配指定字段中包含的任何一個(gè)詞項(xiàng)。

DSL: 查詢(xún)當(dāng)前索引中age 為31或者15的數(shù)據(jù)，類(lèi)似mysql的age in (‘15’,‘31’)

GET dsl_index/_search
{
  "query": {
    "terms": {
      "age": ["31","15"]
    }
  }
}

返回結(jié)果如下:
{
  "took" : 13,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "name" : "王五",
          "age" : 15,
          "description" : "北京市 籃球兩年半"
        }
      },
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "7",
        "_score" : 1.0,
        "_source" : {
          "name" : "小七",
          "age" : 31,
          "description" : "北京市 游泳"
        }
      }
    ]
  }
}

springboot實(shí)現(xiàn):

    @RequestMapping(value = "/terms", method = RequestMethod.GET)
    @ApiOperation(value = "DSL - terms")
    public void terms() throws Exception {
        // 定義請(qǐng)求對(duì)象
        SearchRequest searchRequest = new SearchRequest(INDEX_NAME);
        // 查詢(xún)
        searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.termsQuery("age", new String[]{"15", "31"})));
        // 打印返回?cái)?shù)據(jù)
        printLog(client.search(searchRequest, RequestOptions.DEFAULT));
    }
    
返回結(jié)果如下:
{name=王五, description=北京市 籃球兩年半, age=15}
{name=小七, description=北京市 游泳, age=31}

Exists Query

在Elasticsearch中可以使用exists進(jìn)行查詢(xún)，判斷文檔中是否存在對(duì)應(yīng)的字段。

DSL: 判斷當(dāng)前索引中是否存在sex字段

GET dsl_index/_search
{
  "query": {
    "exists": {
      "field": "sex"
    }
  }
}

返回結(jié)果如下: 很明顯返回值hits中并無(wú)數(shù)據(jù),說(shuō)明當(dāng)前索引中沒(méi)有sex字段
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 0,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  }
}

springboot實(shí)現(xiàn):

    @RequestMapping(value = "/exists", method = RequestMethod.GET)
    @ApiOperation(value = "DSL - exists")
    public void exists() throws Exception {
        // 定義請(qǐng)求對(duì)象
        SearchRequest searchRequest = new SearchRequest(INDEX_NAME);
        // 查詢(xún)
        searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.existsQuery("sex")));
        // 打印返回?cái)?shù)據(jù)
        SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT)
        SearchHits hits = searchResponse.getHits();
        System.out.println("返回hits數(shù)組長(zhǎng)度:" + hits.getHits().length);
    }

返回結(jié)果如下:
返回hits數(shù)組長(zhǎng)度:0

Ids Query

ids 關(guān)鍵字 : 值為每條文檔的默認(rèn)主鍵,根據(jù)一組id獲取多個(gè)對(duì)應(yīng)的文檔

DSL: 查詢(xún)_id為1或者2的數(shù)據(jù)

GET dsl_index/_search
{
  "query": {
    "ids": {
      "values": [1,2]
    }
  }
}

返回?cái)?shù)據(jù)如下:
{
  "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" : "dsl_index",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "name" : "張三",
          "age" : 11,
          "description" : "南京市 羽毛球愛(ài)好者"
        }
      },
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "name" : "王五",
          "age" : 15,
          "description" : "北京市 籃球兩年半"
        }
      }
    ]
  }
}

springboot實(shí)現(xiàn):

    @RequestMapping(value = "/ids", method = RequestMethod.GET)
    @ApiOperation(value = "DSL - ids")
    public void ids() throws Exception {
        // 定義請(qǐng)求對(duì)象
        SearchRequest searchRequest = new SearchRequest(INDEX_NAME);
        // 第一種方式
        // searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.termsQuery("_id","1","2")));
        // 第二種方式
        searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.idsQuery().addIds(new String[]{"1","2"})));
        // 打印返回?cái)?shù)據(jù)
        printLog(client.search(searchRequest, RequestOptions.DEFAULT));
    }

返回結(jié)果如下:
{name=張三, description=南京市 羽毛球愛(ài)好者, age=11}
{name=王五, description=北京市 籃球兩年半, age=15}

Range Query

范圍查詢(xún):

• range：范圍關(guān)鍵字
• gte 大于等于
• lte 小于等于
• gt 大于
• lt 小于
• now 當(dāng)前時(shí)間

DSL: 查詢(xún)當(dāng)前索引下age>=20且age<=30的數(shù)據(jù)

GET dsl_index/_search
{
  "query": {
    "range": {
      "age": {
        "gte": 20,
        "lte": 30
      }
    }
  }
}

返回?cái)?shù)據(jù)如下:
{
  "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" : "dsl_index",
        "_type" : "_doc",
        "_id" : "4",
        "_score" : 1.0,
        "_source" : {
          "name" : "富貴",
          "age" : 22,
          "description" : "天津市 游泳打球"
        }
      },
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "6",
        "_score" : 1.0,
        "_source" : {
          "name" : "憨憨",
          "age" : 27,
          "description" : "北京市 健身打球"
        }
      }
    ]
  }
}

springboot:

    @RequestMapping(value = "/range", method = RequestMethod.GET)
    @ApiOperation(value = "DSL - range")
    public void range() throws Exception {
        // 定義請(qǐng)求對(duì)象
        SearchRequest searchRequest = new SearchRequest(INDEX_NAME);
        // 查詢(xún)
        searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.rangeQuery("age").gte(20).lte(30)));
        // 打印返回?cái)?shù)據(jù)
        printLog(client.search(searchRequest, RequestOptions.DEFAULT));
    }

返回結(jié)果如下:
{name=富貴, description=天津市 游泳打球, age=22}
{name=憨憨, description=北京市 健身打球, age=27}

Prefix Query

前綴查詢(xún) :

• 它不會(huì)分析要搜索字符串，傳入的前綴就是想要查找的前綴
• prefix的原理：需要遍歷所有倒排索引，并比較每個(gè)term是否以所指定的前綴開(kāi)頭。
  此時(shí)當(dāng)前索引中的數(shù)據(jù)如下:
• 默認(rèn)狀態(tài)下，前綴查詢(xún)不做相關(guān)度分?jǐn)?shù)計(jì)算，它只是將所有匹配的文檔返回，然后賦予所有相關(guān)分?jǐn)?shù)值為1。它的行為更像是一個(gè)過(guò)濾器而不是查詢(xún)。兩者實(shí)際的區(qū)別就是過(guò)濾器是可以被緩存的，而前綴查詢(xún)不行。

{name=張三, description=南京市 羽毛球愛(ài)好者, age=11}
{name=王五, description=北京市 籃球兩年半, age=15}
{name=李四, description=山東省 游泳健身, age=18}
{name=富貴, description=天津市 游泳打球, age=22}
{name=來(lái)福, description=安徽合肥 職業(yè)代練, age=8}
{name=憨憨, description=北京市 健身打球, age=27}
{name=小七, description=北京市 游泳, age=31}

DSL: 查詢(xún)description以 "南"開(kāi)頭的數(shù)據(jù)

GET  dsl_index/_search
{
  "query": {
    "prefix": {
      "description": {
        "value": "南"
      }
    }
  }
}
返回?cái)?shù)據(jù)如下:
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "name" : "張三",
          "age" : 11,
          "description" : "南京市 羽毛球愛(ài)好者"
        }
      }
    ]
  }
}

springboot實(shí)現(xiàn):

    @RequestMapping(value = "/prefix", method = RequestMethod.GET)
    @ApiOperation(value = "DSL - prefix")
    public void prefix() throws Exception {
        // 定義請(qǐng)求對(duì)象
        SearchRequest searchRequest = new SearchRequest(INDEX_NAME);
        // 查詢(xún)
        searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.prefixQuery("description","南")));
        // 打印返回?cái)?shù)據(jù)
        printLog(client.search(searchRequest, RequestOptions.DEFAULT));
    }

返回?cái)?shù)據(jù)如下:
{name=張三, description=南京市 羽毛球愛(ài)好者, age=11}

疑問(wèn)： 查詢(xún)description以 “南” 開(kāi)頭有數(shù)據(jù)返回，查詢(xún) “南京” 開(kāi)頭的無(wú)數(shù)據(jù)返回

DSL:

GET  dsl_index/_search
{
  "query": {
    "prefix": {
      "description": {
        "value": "南京"
      }
    }
  }
}

返回結(jié)果如下:
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 0,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  }
}

原因: 這就是上文說(shuō)到的，prefix的原理是不對(duì)查詢(xún)的數(shù)據(jù)分詞，用查詢(xún)的數(shù)據(jù)直接遍歷所有倒排索引
而我們?cè)趧?chuàng)建索引的時(shí)候,description字段使用的是默認(rèn)分詞器 “standard”，該分詞器會(huì)把輸入的每個(gè)字符單獨(dú)拆分，比方說(shuō)把 "南京市 " 拆分成 “南”，“京”，“市”，顧而通過(guò) “南” 字符去匹配能查詢(xún)到數(shù)據(jù)，而通過(guò) “南京” 去匹配無(wú)數(shù)據(jù)

分詞器 “standard” 解析 “南京市” 如下：

POST _analyze
{
  "analyzer": "standard",
  "text": ["南京市"]
}

結(jié)果如下:
{
  "tokens" : [
    {
      "token" : "南",
      "start_offset" : 0,
      "end_offset" : 1,
      "type" : "<IDEOGRAPHIC>",
      "position" : 0
    },
    {
      "token" : "京",
      "start_offset" : 1,
      "end_offset" : 2,
      "type" : "<IDEOGRAPHIC>",
      "position" : 1
    },
    {
      "token" : "市",
      "start_offset" : 2,
      "end_offset" : 3,
      "type" : "<IDEOGRAPHIC>",
      "position" : 2
    }
  ]
}

那么我們?nèi)绻拖胪ㄟ^(guò) “南京” 去搜索到數(shù)據(jù)如何實(shí)現(xiàn)呢？可以在創(chuàng)建索引的時(shí)候，指定字段分詞器為
“ik_max_word”，該分詞器劃分粒度比較細(xì)，當(dāng)然也可以指定其它分詞器或者自定義分詞器，看場(chǎng)景需要，如下是 “ik_max_word” 分詞器解析 “南京市” :

POST _analyze
{
  "analyzer": "ik_max_word",
  "text": ["南京市"]
}

結(jié)果如下:
{
  "tokens" : [
    {
      "token" : "南京市",
      "start_offset" : 0,
      "end_offset" : 3,
      "type" : "CN_WORD",
      "position" : 0
    },
    {
      "token" : "南京",
      "start_offset" : 0,
      "end_offset" : 2,
      "type" : "CN_WORD",
      "position" : 1
    },
    {
      "token" : "市",
      "start_offset" : 2,
      "end_offset" : 3,
      "type" : "CN_CHAR",
      "position" : 2
    }
  ]
}

Wildcard Query

通配符查詢(xún)：工作原理和prefix相同，只不過(guò)它不是只比較開(kāi)頭，它能支持更為復(fù)雜的匹配模式。
注意：其實(shí)無(wú)論是前綴匹配還是通配符查詢(xún)，針對(duì)的都是倒排索引。

DSL: 查詢(xún)當(dāng)前索引下description字段中含有 “籃” 的數(shù)據(jù)

GET  dsl_index/_search
{
  "query": {
    "prefix": {
      "description": {
        "value": "籃"
      }
    }
  }
}

返回結(jié)果如下:
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "name" : "王五",
          "age" : 15,
          "description" : "北京市 籃球兩年半"
        }
      }
    ]
  }
}

springboot實(shí)現(xiàn)：

    @RequestMapping(value = "/wildcard", method = RequestMethod.GET)
    @ApiOperation(value = "DSL - wildcard")
    public void wildcard() throws Exception {
        // 定義請(qǐng)求對(duì)象
        SearchRequest searchRequest = new SearchRequest(INDEX_NAME);
        // 查詢(xún)
        searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.wildcardQuery("description","籃")));
        // 打印返回?cái)?shù)據(jù)
        printLog(client.search(searchRequest, RequestOptions.DEFAULT));
    }

返回結(jié)果如下:
{name=王五, description=北京市 籃球兩年半, age=15}

Fuzzy Query

模糊查詢(xún):

在實(shí)際的搜索中，我們有時(shí)候會(huì)打錯(cuò)字，從而導(dǎo)致搜索不到。在Elasticsearch中，我們可以使用fuzziness屬性來(lái)進(jìn)行模糊查詢(xún)，從而達(dá)到搜索有錯(cuò)別字的情形。

fuzzy 查詢(xún)會(huì)用到兩個(gè)很重要的參數(shù)，fuzziness，prefix_length

• fuzziness：表示輸入的關(guān)鍵字通過(guò)幾次操作可以轉(zhuǎn)變成為ES庫(kù)里面的對(duì)應(yīng)field的字段
  • 操作是指：新增一個(gè)字符，刪除一個(gè)字符，修改一個(gè)字符，每次操作可以記做編輯距離為1;
  • 如中文集團(tuán)到中威集團(tuán)編輯距離就是1，只需要修改一個(gè)字符；如果fuzziness值在這里設(shè)置成2，會(huì)把編輯距離為2的東東集團(tuán)也查出來(lái)。
  • 該參數(shù)默認(rèn)值為0，即不開(kāi)啟模糊查詢(xún); fuzzy 模糊查詢(xún) 最大模糊錯(cuò)誤必須在0-2之間
• prefix_length：表示限制輸入關(guān)鍵字和ES對(duì)應(yīng)查詢(xún)field的內(nèi)容開(kāi)頭的第n個(gè)字符必須完全匹配，不允許錯(cuò)別字匹配;
  • 如這里等于1，則表示開(kāi)頭的字必須匹配，不匹配則不返回;
  • 默認(rèn)值也是0;
  • 加大prefix_length的值可以提高效率和準(zhǔn)確率。

DSL: 此時(shí)我們索引中有以下的數(shù)據(jù):{name=王五, description=北京市 籃球兩年半, age=15}
我們搜索description字段值為 “北京市 足球兩年半” 故意輸錯(cuò)一個(gè)字符

1.當(dāng)設(shè)置fuzziness=0時(shí):
GET  dsl_index/_search
{
  "query": {
    "fuzzy": {
      "description.keyword": {
        "value": "北京市 足球兩年半",
        "fuzziness": 0
      }
    }
  }
}
無(wú)數(shù)據(jù)返回,如下:
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 0,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  }
}

2.當(dāng)設(shè)置fuzziness=1時(shí):
GET  dsl_index/_search
{
  "query": {
    "fuzzy": {
      "description.keyword": {
        "value": "北京市 足球兩年半",
        "fuzziness": 1
      }
    }
  }
}

返回?cái)?shù)據(jù)如下:
{
  "took" : 2,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.4879789,
    "hits" : [
      {
        "_index" : "dsl_index",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.4879789,
        "_source" : {
          "name" : "王五",
          "age" : 15,
          "description" : "北京市 籃球兩年半"
        }
      }
    ]
  }
}

springboot實(shí)現(xiàn):

搜索description字段值為 "北京市 足球兩年半",并且可以錯(cuò)一個(gè)字符:
    @RequestMapping(value = "/fuzzy", method = RequestMethod.GET)
    @ApiOperation(value = "DSL - fuzzy")
    public void fuzzy() throws Exception {
        // 定義請(qǐng)求對(duì)象
        SearchRequest searchRequest = new SearchRequest(INDEX_NAME);
        // 查詢(xún)
        searchRequest.source(new SearchSourceBuilder().query(
                QueryBuilders.fuzzyQuery("description.keyword","北京市 籃球2年半").fuzziness(Fuzziness.ONE)));
        // 打印返回?cái)?shù)據(jù)
        printLog(client.search(searchRequest, RequestOptions.DEFAULT));
    }

返回?cái)?shù)據(jù)如下:
{name=王五, description=北京市 籃球兩年半, age=15}

以上就是Query DSL術(shù)語(yǔ)級(jí)別查詢(xún)并結(jié)合springboot的使用方法,后期繼續(xù)介紹全文檢索結(jié)合springboot使用。文章來(lái)源地址http://www.zghlxwxcb.cn/news/detail-790232.html

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