es - elasticsearch自定义分析器 - 内建分词器 - 3世界上并没有完美的程序，但是我们并不因此而沮丧，

世界上并没有完美的程序，但是我们并不因此而沮丧，因为写程序就是一个不断追求完美的过程。

自定义分析器 :

Character filters :
1. 作用 : 字符的增、删、改转换
2. 数量限制 : 可以有0个或多个
3. 内建字符过滤器 :
1. HTML Strip Character filter : 去除html标签
2. Mapping Character filter : 映射替换
3. Pattern Replace Character filter : 正则替换
Tokenizer :
1. 作用 :
1. 分词
2. 记录词的顺序和位置（短语查询）
3. 记录词的开头和结尾位置（高亮）
4. 记录词的类型（分类）
2. 数量限制 : 有且只能有一个
3. 分类 :
1. 完整分词 :
1. Standard
2. Letter
3. Lowercase
4. whitespace
5. UAX URL Email
6. Classic
7. Thai
2. 切词 :
1. N-Gram
2. Edge N-Gram
3. 文本 :
1. Keyword
2. Pattern
3. Simple Pattern
4. Char Group
5. Simple Pattern split
6. Path
Token filters :
1. 作用 : 分词的增、删、改转换
2. 数量限制 : 可以有0个或多个

今天演示文本结构的分词器 :

# keyword tokenizer
# 原样返回
GET /_analyze
{
  "tokenizer": "keyword",
  "text": ["hello world", "我是中国人"]
}

# 结果
{
  "tokens" : [
    {
      "token" : "hello world",
      "start_offset" : 0,
      "end_offset" : 11,
      "type" : "word",
      "position" : 0
    },
    {
      "token" : "我是中国人",
      "start_offset" : 12,
      "end_offset" : 17,
      "type" : "word",
      "position" : 101
    }
  ]
}

# pattern tokenizer
# 基于正则的分词，取正则匹配为词
# 配置项 :
#   1. pattern : 正则表达式
#   2. flags
#   3. group   : 组的个数，默认 -1
GET /_analyze
{
  "tokenizer": {
    "type" : "pattern",
    "pattern" : "((?:[a-z0-9])+)",
    "group" : 1
  },
  "text": ["hello 23456"]
}

# 结果
{
  "tokens" : [
    {
      "token" : "hello",
      "start_offset" : 0,
      "end_offset" : 5,
      "type" : "word",
      "position" : 0
    },
    {
      "token" : "23456",
      "start_offset" : 6,
      "end_offset" : 11,
      "type" : "word",
      "position" : 1
    }
  ]
}

# simple pattern analyzer
# 使用lucene的正则，取匹配正则的词
# 必须指定pattern
# 配置项 : pattern
GET /_analyze
{
  "tokenizer": {
    "type" : "simple_pattern",
    "pattern" : "[0-9]{3}" 
  },
  "text": ["3456786544433 fsdfsd"]
}

# 结果
{
  "tokens" : [
    {
      "token" : "345",
      "start_offset" : 0,
      "end_offset" : 3,
      "type" : "word",
      "position" : 0
    },
    {
      "token" : "678",
      "start_offset" : 3,
      "end_offset" : 6,
      "type" : "word",
      "position" : 1
    },
    {
      "token" : "654",
      "start_offset" : 6,
      "end_offset" : 9,
      "type" : "word",
      "position" : 2
    },
    {
      "token" : "443",
      "start_offset" : 9,
      "end_offset" : 12,
      "type" : "word",
      "position" : 3
    }
  ]
}

# char group tokenizer
# 基于指定字符分词
# 配置项 :
#   1. tokenize_on_chars : 分词的字符
#   2. max_token_length
GET /_analyze
{
  "tokenizer": {
    "type" : "char_group",
    "tokenize_on_chars" : [
        "-", "whitespace", "_"
      ]
  },
  "text": ["sdjflds sdfsd-sdf-7879 fsd_us9098"]
}

# 结果
{
  "tokens" : [
    {
      "token" : "sdjflds",
      "start_offset" : 0,
      "end_offset" : 7,
      "type" : "word",
      "position" : 0
    },
    {
      "token" : "sdfsd",
      "start_offset" : 8,
      "end_offset" : 13,
      "type" : "word",
      "position" : 1
    },
    {
      "token" : "sdf",
      "start_offset" : 14,
      "end_offset" : 17,
      "type" : "word",
      "position" : 2
    },
    {
      "token" : "7879",
      "start_offset" : 18,
      "end_offset" : 22,
      "type" : "word",
      "position" : 3
    },
    {
      "token" : "fsd",
      "start_offset" : 23,
      "end_offset" : 26,
      "type" : "word",
      "position" : 4
    },
    {
      "token" : "us9098",
      "start_offset" : 27,
      "end_offset" : 33,
      "type" : "word",
      "position" : 5
    }
  ]
}

# simple pattern split tokenizer
# 以正则分词
# 配置项 : pattern
GET /_analyze
{
  "tokenizer": {
    "type" : "simple_pattern_split",
    "pattern" : "[0-9]{3}"
  },
  "text": ["sdfsd23243sdfsd890sdfs"]
}

# 结果
{
  "tokens" : [
    {
      "token" : "sdfsd",
      "start_offset" : 0,
      "end_offset" : 5,
      "type" : "word",
      "position" : 0
    },
    {
      "token" : "43sdfsd",
      "start_offset" : 8,
      "end_offset" : 15,
      "type" : "word",
      "position" : 1
    },
    {
      "token" : "sdfs",
      "start_offset" : 18,
      "end_offset" : 22,
      "type" : "word",
      "position" : 2
    }
  ]
}

# path hierarchy tokenizer
# 路径拆分及转换
# 配置项 :
#   1. delimiter   : 拆分字符
#   2. replacement : 替换字符
#   3. buffer_size : 不建议修改
#   4. reverse     : 默认 false
#       1. 分出的路径的显示顺序反转
#       2. skip的位置的反转
#   5. skip        : 初始位置，默认 0
GET /_analyze
{
  "tokenizer": {
    "type"        : "path_hierarchy",
    "delimiter"   : "-",
    "replacement" : "/",
    "reverse"     : true,
    "skip"        : 1
  },
  "text": ["hello-good-this-is-me"]
}

# 结果
{
  "tokens" : [
    {
      "token" : "hello/good/this/is/",
      "start_offset" : 0,
      "end_offset" : 19,
      "type" : "word",
      "position" : 0
    },
    {
      "token" : "good/this/is/",
      "start_offset" : 6,
      "end_offset" : 19,
      "type" : "word",
      "position" : 0
    },
    {
      "token" : "this/is/",
      "start_offset" : 11,
      "end_offset" : 19,
      "type" : "word",
      "position" : 0
    },
    {
      "token" : "is/",
      "start_offset" : 16,
      "end_offset" : 19,
      "type" : "word",
      "position" : 0
    }
  ]
}