ElasticSearch（三）：通过分词器（Analyzer）进行分词（Analysis）
## Analysis与Analyzer * Analysis文本分析就是把全文转换成一系列单词的过程，也叫做分词。 * Analysis是通过Analyzer来实现的，它是专门处理分词的组件。可以使用ElasticSearch内置的分词器，也可以按需定制化分词器。 * 除了在数据写入时用分词器转换词条，在匹配查询语句时，也需要用相同的分词器对查询语句进行分析。
Analyzer的组成
分词器是专门处理分词的组件，Analyzer由三个部分组成：
- Character Filters：主要作用是对原始文本进行处理，例如去除HTML标签。
- Tokenizer：主要作用是按照规则来切分单词。
- Token Filter：将切分好的单词进行加工，例如：小写转换、删除停用词、增加同义词。
ElasticSearch的内置分词器
- Standard Analyzer：默认分词器，按词切分，小写处理。
#standard
GET _analyze
{
"analyzer": "standard",
"text": "2 running Quick brown-foxes leap over lazy dogs in the summer evening."
}
#分词结果：Quick小写处理， brown-foxes被切分为 brown，foxes
{
"tokens" : [
{
"token" : "2",
"start_offset" : 0,
"end_offset" : 1,
"type" : "<NUM>",
"position" : 0
},
{
"token" : "running",
"start_offset" : 2,
"end_offset" : 9,
"type" : "<ALPHANUM>",
"position" : 1
},
{
"token" : "quick",#小写处理
"start_offset" : 10,
"end_offset" : 15,
"type" : "<ALPHANUM>",
"position" : 2
},
{
"token" : "brown",
"start_offset" : 16,
"end_offset" : 21,
"type" : "<ALPHANUM>",
"position" : 3
},
{
"token" : "foxes",
"start_offset" : 22,
"end_offset" : 27,
"type" : "<ALPHANUM>",
"position" : 4
},
{
"token" : "leap",
"start_offset" : 28,
"end_offset" : 32,
"type" : "<ALPHANUM>",
"position" : 5
},
{
"token" : "over",
"start_offset" : 33,
"end_offset" : 37,
"type" : "<ALPHANUM>",
"position" : 6
},
{
"token" : "lazy",
"start_offset" : 38,
"end_offset" : 42,
"type" : "<ALPHANUM>",
"position" : 7
},
{
"token" : "dogs",
"start_offset" : 43,
"end_offset" : 47,
"type" : "<ALPHANUM>",
"position" : 8
},
{
"token" : "in",
"start_offset" : 48,
"end_offset" : 50,
"type" : "<ALPHANUM>",
"position" : 9
},
{
"token" : "the",
"start_offset" : 51,
"end_offset" : 54,
"type" : "<ALPHANUM>",
"position" : 10
},
{
"token" : "summer",
"start_offset" : 55,
"end_offset" : 61,
"type" : "<ALPHANUM>",
"position" : 11
},
{
"token" : "evening",
"start_offset" : 62,
"end_offset" : 69,
"type" : "<ALPHANUM>",
"position" : 12
}
]
}
- Simple Analyzer：按照非字母切分（符号被过滤），小写处理。
#simpe
GET _analyze
{
"analyzer": "simple",
"text": "2 running Quick brown-foxes leap over lazy dogs in the summer evening."
}
#分词结果：数字2被过滤，Quick小写处理， brown-foxes被切分为 brown，foxes
{
"tokens" : [
{
"token" : "running",
"start_offset" : 2,
"end_offset" : 9,
"type" : "word",
"position" : 0
},
{
"token" : "quick",
"start_offset" : 10,
"end_offset" : 15,
"type" : "word",
"position" : 1
},
{
"token" : "brown",
"start_offset" : 16,
"end_offset" : 21,
"type" : "word",
"position" : 2
},
{
"token" : "foxes",
"start_offset" : 22,
"end_offset" : 27,
"type" : "word",
"position" : 3
},
{
"token" : "leap",
"start_offset" : 28,
"end_offset" : 32,
"type" : "word",
"position" : 4
},
{
"token" : "over",
"start_offset" : 33,
"end_offset" : 37,
"type" : "word",
"position" : 5
},
{
"token" : "lazy",
"start_offset" : 38,
"end_offset" : 42,
"type" : "word",
"position" : 6
},
{
"token" : "dogs",
"start_offset" : 43,
"end_offset" : 47,
"type" : "word",
"position" : 7
},
{
"token" : "in",
"start_offset" : 48,
"end_offset" : 50,
"type" : "word",
"position" : 8
},
{
"token" : "the",
"start_offset" : 51,
"end_offset" : 54,
"type" : "word",
"position" : 9
},
{
"token" : "summer",
"start_offset" : 55,
"end_offset" : 61,
"type" : "word",
"position" : 10
},
{
"token" : "evening",
"start_offset" : 62,
"end_offset" : 69,
"type" : "word",
"position" : 11
}
]
}
- Stop Analyzer：停用词过滤（is/a/the），小写处理。
#stop
GET _analyze
{
"analyzer": "stop",
"text": "2 running Quick brown-foxes leap over lazy dogs in the summer evening."
}
#分词结果：2，in，the被过滤，Quick小写处理， brown-foxes被切分为 brown，foxes
{
"tokens" : [
{
"token" : "running",
"start_offset" : 2,
"end_offset" : 9,
"type" : "word",
"position" : 0
},
{
"token" : "quick",
"start_offset" : 10,
"end_offset" : 15,
"type" : "word",
"position" : 1
},
{
"token" : "brown",
"start_offset" : 16,
"end_offset" : 21,
"type" : "word",
"position" : 2
},
{
"token" : "foxes",
"start_offset" : 22,
"end_offset" : 27,
"type" : "word",
"position" : 3
},
{
"token" : "leap",
"start_offset" : 28,
"end_offset" : 32,
"type" : "word",
"position" : 4
},
{
"token" : "over",
"start_offset" : 33,
"end_offset" : 37,
"type" : "word",
"position" : 5
},
{
"token" : "lazy",
"start_offset" : 38,
"end_offset" : 42,
"type" : "word",
"position" : 6
},
{
"token" : "dogs",
"start_offset" : 43,
"end_offset" : 47,
"type" : "word",
"position" : 7
},
{
"token" : "summer",
"start_offset" : 55,
"end_offset" : 61,
"type" : "word",
"position" : 10
},
{
"token" : "evening",
"start_offset" : 62,
"end_offset" : 69,
"type" : "word",
"position" : 11
}
]
}
- WhiteSpace Analyzer：按照空格切分，不转小写。
#whitespace
GET _analyze
{
"analyzer": "whitespace",
"text": "2 running Quick brown-foxes leap over lazy dogs in the summer evening."
}
#分词结果：按空格切分
{
"tokens" : [
{
"token" : "2",
"start_offset" : 0,
"end_offset" : 1,
"type" : "word",
"position" : 0
},
{
"token" : "running",
"start_offset" : 2,
"end_offset" : 9,
"type" : "word",
"position" : 1
},
{
"token" : "Quick",
"start_offset" : 10,
"end_offset" : 15,
"type" : "word",
"position" : 2
},
{
"token" : "brown-foxes",
"start_offset" : 16,
"end_offset" : 27,
"type" : "word",
"position" : 3
},
{
"token" : "leap",
"start_offset" : 28,
"end_offset" : 32,
"type" : "word",
"position" : 4
},
{
"token" : "over",
"start_offset" : 33,
"end_offset" : 37,
"type" : "word",
"position" : 5
},
{
"token" : "lazy",
"start_offset" : 38,
"end_offset" : 42,
"type" : "word",
"position" : 6
},
{
"token" : "dogs",
"start_offset" : 43,
"end_offset" : 47,
"type" : "word",
"position" : 7
},
{
"token" : "in",
"start_offset" : 48,
"end_offset" : 50,
"type" : "word",
"position" : 8
},
{
"token" : "the",
"start_offset" : 51,
"end_offset" : 54,
"type" : "word",
"position" : 9
},
{
"token" : "summer",
"start_offset" : 55,
"end_offset" : 61,
"type" : "word",
"position" : 10
},
{
"token" : "evening.",
"start_offset" : 62,
"end_offset" : 70,
"type" : "word",
"position" : 11
}
]
}
- Keyword Analyzer：不分词，直接将输入当作输出。
#keyword
GET _analyze
{
"analyzer": "keyword",
"text": "2 running Quick brown-foxes leap over lazy dogs in the summer evening."
}
#分词结果：
{
"tokens" : [
{
"token" : "2 running Quick brown-foxes leap over lazy dogs in the summer evening.",
"start_offset" : 0,
"end_offset" : 70,
"type" : "word",
"position" : 0
}
]
}
- Pattern Analyzer：正则表达式分词，默认W+（非字符分隔）。
#pattern
GET _analyze
{
"analyzer": "pattern",
"text": "2 running Quick brown-foxes leap over lazy dogs in the summer evening."
}
#分词结果：
{
"tokens" : [
{
"token" : "2",
"start_offset" : 0,
"end_offset" : 1,
"type" : "word",
"position" : 0
},
{
"token" : "running",
"start_offset" : 2,
"end_offset" : 9,
"type" : "word",
"position" : 1
},
{
"token" : "quick",
"start_offset" : 10,
"end_offset" : 15,
"type" : "word",
"position" : 2
},
{
"token" : "brown",
"start_offset" : 16,
"end_offset" : 21,
"type" : "word",
"position" : 3
},
{
"token" : "foxes",
"start_offset" : 22,
"end_offset" : 27,
"type" : "word",
"position" : 4
},
{
"token" : "leap",
"start_offset" : 28,
"end_offset" : 32,
"type" : "word",
"position" : 5
},
{
"token" : "over",
"start_offset" : 33,
"end_offset" : 37,
"type" : "word",
"position" : 6
},
{
"token" : "lazy",
"start_offset" : 38,
"end_offset" : 42,
"type" : "word",
"position" : 7
},
{
"token" : "dogs",
"start_offset" : 43,
"end_offset" : 47,
"type" : "word",
"position" : 8
},
{
"token" : "in",
"start_offset" : 48,
"end_offset" : 50,
"type" : "word",
"position" : 9
},
{
"token" : "the",
"start_offset" : 51,
"end_offset" : 54,
"type" : "word",
"position" : 10
},
{
"token" : "summer",
"start_offset" : 55,
"end_offset" : 61,
"type" : "word",
"position" : 11
},
{
"token" : "evening",
"start_offset" : 62,
"end_offset" : 69,
"type" : "word",
"position" : 12
}
]
}
- Language：提供了30多种常见语言的分词器。
#english
GET _analyze
{
"analyzer": "english",
"text": "2 running Quick brown-foxes leap over lazy dogs in the summer evening."
}
#分词结果：running转为run，Quick转为quick，brown-foxes 转为brown、fox，in、the过滤等等
{
"tokens" : [
{
"token" : "2",
"start_offset" : 0,
"end_offset" : 1,
"type" : "<NUM>",
"position" : 0
},
{
"token" : "run",
"start_offset" : 2,
"end_offset" : 9,
"type" : "<ALPHANUM>",
"position" : 1
},
{
"token" : "quick",
"start_offset" : 10,
"end_offset" : 15,
"type" : "<ALPHANUM>",
"position" : 2
},
{
"token" : "brown",
"start_offset" : 16,
"end_offset" : 21,
"type" : "<ALPHANUM>",
"position" : 3
},
{
"token" : "fox",
"start_offset" : 22,
"end_offset" : 27,
"type" : "<ALPHANUM>",
"position" : 4
},
{
"token" : "leap",
"start_offset" : 28,
"end_offset" : 32,
"type" : "<ALPHANUM>",
"position" : 5
},
{
"token" : "over",
"start_offset" : 33,
"end_offset" : 37,
"type" : "<ALPHANUM>",
"position" : 6
},
{
"token" : "lazi",
"start_offset" : 38,
"end_offset" : 42,
"type" : "<ALPHANUM>",
"position" : 7
},
{
"token" : "dog",
"start_offset" : 43,
"end_offset" : 47,
"type" : "<ALPHANUM>",
"position" : 8
},
{
"token" : "summer",
"start_offset" : 55,
"end_offset" : 61,
"type" : "<ALPHANUM>",
"position" : 11
},
{
"token" : "even",
"start_offset" : 62,
"end_offset" : 69,
"type" : "<ALPHANUM>",
"position" : 12
}
]
}
- Custom Analyzer：自定义分词器。
#需要安装analysis-icu插件
POST _analyze
{
"analyzer": "icu_analyzer",
"text": "他说的确实在理”"
}
#返回结果
{
"tokens" : [
{
"token" : "他",
"start_offset" : 0,
"end_offset" : 1,
"type" : "<IDEOGRAPHIC>",
"position" : 0
},
{
"token" : "说的",
"start_offset" : 1,
"end_offset" : 3,
"type" : "<IDEOGRAPHIC>",
"position" : 1
},
{
"token" : "确实",
"start_offset" : 3,
"end_offset" : 5,
"type" : "<IDEOGRAPHIC>",
"position" : 2
},
{
"token" : "在",
"start_offset" : 5,
"end_offset" : 6,
"type" : "<IDEOGRAPHIC>",
"position" : 3
},
{
"token" : "理",
"start_offset" : 6,
"end_offset" : 7,
"type" : "<IDEOGRAPHIC>",
"position" : 4
}
]
}
中文分词比较：
POST _analyze
{
"analyzer": "standard",
"text": "他说的确实在理”"
}
#返回结果
{
"tokens" : [
{
"token" : "他",
"start_offset" : 0,
"end_offset" : 1,
"type" : "<IDEOGRAPHIC>",
"position" : 0
},
{
"token" : "说",
"start_offset" : 1,
"end_offset" : 2,
"type" : "<IDEOGRAPHIC>",
"position" : 1
},
{
"token" : "的",
"start_offset" : 2,
"end_offset" : 3,
"type" : "<IDEOGRAPHIC>",
"position" : 2
},
{
"token" : "确",
"start_offset" : 3,
"end_offset" : 4,
"type" : "<IDEOGRAPHIC>",
"position" : 3
},
{
"token" : "实",
"start_offset" : 4,
"end_offset" : 5,
"type" : "<IDEOGRAPHIC>",
"position" : 4
},
{
"token" : "在",
"start_offset" : 5,
"end_offset" : 6,
"type" : "<IDEOGRAPHIC>",
"position" : 5
},
{
"token" : "理",
"start_offset" : 6,
"end_offset" : 7,
"type" : "<IDEOGRAPHIC>",
"position" : 6
}
]
}