ElasticSearch(7.2.2)-分詞器的介紹和使⽤

• 2019 年 11 月 4 日
• 筆記

簡介：分詞器是什麼，內置的分詞器有哪些

什麼是分詞器

• 將⽤戶輸⼊的⼀段⽂本，按照⼀定邏輯，分析成多個詞語的⼀種⼯具
• example: The best 3-points shooter is Curry!

常用的內置分詞器

• standard analyzer
• simple analyzer
• whitespace analyzer
• stop analyzer
• language analyzer
• pattern analyzer

standard analyzer

• 標準分析器是默認分詞器，如果未指定，則使⽤該分詞器。
• POST localhost:9200/_analyze

{  	 "analyzer": "standard",  	 "text": "The best 3-points shooter is Curry!"  }

simple analyzer

• simple 分析器當它遇到只要不是字⺟的字元，就將⽂本解析成term，⽽且所有的term都是⼩寫的。
• POST localhost:9200/_analyze

{  	 "analyzer": "simple",  	 "text": "The best 3-points shooter is Curry!"  }

whitespace analyzer

• whitespace 分析器，當它遇到空⽩字元時，就將⽂本解析成terms
• POST localhost:9200/_analyze

{  	 "analyzer": "whitespace",  	 "text": "The best 3-points shooter is Curry!"  }

stop analyzer

• stop 分析器 和 simple 分析器很像，唯⼀不同的是，stop 分析器增加了對刪除停⽌詞的⽀持，默認使⽤了english停⽌詞
• stop words 預定義的停⽌詞列表，⽐如 (the,a,an,this,of,at)等等
• POST localhost:9200/_analyze

{  	 "analyzer": "whitespace",  	 "text": "The best 3-points shooter is Curry!"  }

language analyzer

• （特定的語⾔的分詞器，⽐如說，English[英語分詞器]),內置語⾔：arabic, armenian,basque, bengali, brazilian, bulgarian, catalan, cjk, czech, danish, dutch, english, finnish,french, galician, german, greek, hindi, hungarian, indonesian, irish, italian, latvian,lithuanian, norwegian, persian, portuguese, romanian, russian, sorani, spanish,swedish, turkish, thai
• POST localhost:9200/_analyze

{  	 "analyzer": "english",  	 "text": "The best 3-points shooter is Curry!"  }

pattern analyzer

• ⽤正則表達式來將⽂本分割成terms，默認的正則表達式是W+（⾮單詞字元）
• POST localhost:9200/_analyze

{  	 "analyzer": "pattern",  	 "text": "The best 3-points shooter is Curry!"  }

選擇分詞器

• PUT localhost:9200/my_index

{  	"settings": {  		"analysis": {  			"analyzer": {  				"my_analyzer": {  					"type": "whitespace"  				}  			}  		}  	},  	"mappings": {  		"properties": {  			"name": {  				"type": "text"  			},  			"team_name": {  				"type": "text"  			},  			"position": {  				"type": "text"  			},  			"play_year": {  				"type": "long"  			},  			"jerse_no": {  				"type": "keyword"  			},  			"title": {  				"type": "text",  				"analyzer": "my_analyzer"  			}  		}  	}  }

• PUT localhost:9200/my_index/_doc/1

{  	 "name": "庫⾥",  	 "team_name": "勇⼠",  	 "position": "控球後衛",  	 "play_year": 10,  	 "jerse_no": "30",  	 "title": "The best 3-points shooter is Curry!"   }

• POST localhost:9200/my_index/_search

{  	"query": {  		"match": {  			"title": "Curry!"  		}  	}  }