ElasticSearch（二十六）修改分詞器及定製本身的分詞器

一、默認的分詞器

standard 分詞器

standard tokenizer：以單詞邊界進行切分
standard token filter：什麼都不作
lowercase token filter：將全部字母轉換爲小寫
stop token filer（默認被禁用）：移除停用詞，好比a the it等等

二、修改分詞器的設置

啓用english停用詞token filter

PUT /my_index
{
  "settings": {
    "analysis": {
      "analyzer": {
        "es_std": {
          "type": "standard",
          "stopwords": "_english_"
        }
      }
    }
  }
}

GET /my_index/_analyze
{
  "analyzer": "standard", 
  "text": "a dog is in the house"
}

GET /my_index/_analyze
{
  "analyzer": "es_std",
  "text":"a dog is in the house"
}

三、定製化本身的分詞器

1.&字符轉換

2.停用某些詞

3.大小寫轉換

PUT /my_index
{
  "settings": {
    "analysis": {
      "char_filter": {
        "&_to_and": {
          "type": "mapping",
          "mappings": ["&=> and"]
        }
      },
      "filter": {
        "my_stopwords": {
          "type": "stop",
          "stopwords": ["the", "a"]
        }
      },
      "analyzer": {
        "my_analyzer": {
          "type": "custom",
          "char_filter": ["html_strip", "&_to_and"],
          "tokenizer": "standard",
          "filter": ["lowercase", "my_stopwords"]
        }
      }
    }
  }
}

GET /my_index/_analyze
{
  "text": "tom&jerry are a friend in the house, <a>, HAHA!!",
  "analyzer": "my_analyzer"
}

PUT /my_index/_mapping/my_type
{
  "properties": {
    "content": {
      "type": "text",
      "analyzer": "my_analyzer"
    }
  }
}