分词器

1、默认的分词器

standard

包括：

• standard tokenizer：以单词边界进行切分

• standard token filter：什么都不做

• lowercase token filter：将所有字母转换为小写

• stop token filer（默认被禁用）：移除停用词，比如a the it等等

2、修改分词器的设置

启用english停用词 token filter

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

查看分词器处理后的对比结果：

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"
}

3、定制化自己的分词器

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"]
        }
      }
    }
  }
}

查看分词器处理结果：

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

创建mapping时使用分词器

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