【ElasticSearch】04_ElasticSearch之IK分词安装配置

1. IK分词下载安装

1.1 ik分词器的下载

下载地址：https://github.com/medcl/elasticsearch-analysis-ik/releases，这里你需要根据你的Es的版本来下载对应版本的IK，这里我使用的是7.5.1的ES，所以就下载ik-7.5.1.zip的文件

1.2 解压安装

解压-->将文件复制到 es的安装目录/plugin/elasticsearch-analysis-ik-7.5.1下面即可，完成之后效果如下：

解压完成之后重启ElasticSearch服务就可以使用了

2. IK分词器的基本使用

2.1 IK中文分词器

ik_smart: 会做最粗粒度的拆分

GET /_analyze
{
  "text":"中华人民共和国国徽",
  "analyzer":"ik_smart"
}

结果：
{
  "tokens": [
    {
      "token": "中华人民共和国",
      "start_offset": 0,
      "end_offset": 7,
      "type": "CN_WORD",
      "position": 0
    },
    {
      "token": "国徽",
      "start_offset": 7,
      "end_offset": 9,
      "type": "CN_WORD",
      "position": 1
    }
  ]
}

ik_max_word: 会将文本做最细粒度的拆分

GET /_analyze
{
  "text": "中华人民共和国国徽",
  "analyzer": "ik_max_word"
}

结果：
{
  "tokens": [
    {
      "token": "中华人民共和国",
      "start_offset": 0,
      "end_offset": 7,
      "type": "CN_WORD",
      "position": 0
    },
    {
      "token": "中华人民",
      "start_offset": 0,
      "end_offset": 4,
      "type": "CN_WORD",
      "position": 1
    },
    {
      "token": "中华",
      "start_offset": 0,
      "end_offset": 2,
      "type": "CN_WORD",
      "position": 2
    },
    {
      "token": "华人",
      "start_offset": 1,
      "end_offset": 3,
      "type": "CN_WORD",
      "position": 3
    },
    {
      "token": "人民共和国",
      "start_offset": 2,
      "end_offset": 7,
      "type": "CN_WORD",
      "position": 4
    },
    {
      "token": "人民",
      "start_offset": 2,
      "end_offset": 4,
      "type": "CN_WORD",
      "position": 5
    },
    {
      "token": "共和国",
      "start_offset": 4,
      "end_offset": 7,
      "type": "CN_WORD",
      "position": 6
    },
    {
      "token": "共和",
      "start_offset": 4,
      "end_offset": 6,
      "type": "CN_WORD",
      "position": 7
    },
    {
      "token": "国",
      "start_offset": 6,
      "end_offset": 7,
      "type": "CN_CHAR",
      "position": 8
    },
    {
      "token": "国徽",
      "start_offset": 7,
      "end_offset": 9,
      "type": "CN_WORD",
      "position": 9
    }
  ]
}

2.2 IK拼音分词器

GET /_analyze
{
  "text":"刘德华",
  "analyzer": "pinyin"
}

结果:
{
  "tokens": [
    {
      "token": "liu",
      "start_offset": 0,
      "end_offset": 1,
      "type": "word",
      "position": 0
    },
    {
      "token": "ldh",
      "start_offset": 0,
      "end_offset": 3,
      "type": "word",
      "position": 0
    },
    {
      "token": "de",
      "start_offset": 1,
      "end_offset": 2,
      "type": "word",
      "position": 1
    },
    {
      "token": "hua",
      "start_offset": 2,
      "end_offset": 3,
      "type": "word",
      "position": 2
    }
  ]
}

注：不管是拼音分词器还是IK分词器，当深入搜索一条数据是时，必须是通过分词器分析的数据，才能被搜索到，否则搜索不到

2.3 IK分词和拼音分词的组合使用

当我们创建索引时可以自定义分词器，通过指定映射去匹配自定义分词器

PUT /my_index
{
    "settings": {
        "analysis": {
            "analyzer": {
                "ik_smart_pinyin": {
                    "type": "custom",
                    "tokenizer": "ik_smart",
                    "filter": ["my_pinyin", "word_delimiter"]
                },
                "ik_max_word_pinyin": {
                    "type": "custom",
                    "tokenizer": "ik_max_word",
                    "filter": ["my_pinyin", "word_delimiter"]
                }
            },
            "filter": {
                "my_pinyin": {
                    "type" : "pinyin",
                    "keep_separate_first_letter" : true,
                    "keep_full_pinyin" : true,
                    "keep_original" : true,
                    "limit_first_letter_length" : 16,
                    "lowercase" : true,
                    "remove_duplicated_term" : true 
                }
            }
        }
    }
}

当我们建type时，需要在字段的analyzer属性填写自己的映射

PUT /my_index/my_type/_mapping
{
    "my_type":{
        "properties": {
            "id":{
                "type": "integer"
            },
            "name":{
                "type": "text",
                "analyzer": "ik_smart_pinyin"
            }
        }
    }
}