配置es同义词 - 检索分析服务Elasticsearch版

通过使用同义词，您可以将已经上传的同义词文件作用于阿里云Elasticsearch的同义词库，并使用更新后的词库搜索。阿里云Elasticsearch支持两种方式使用同义词：上传同义词文件、直接引用同义词。本文分别介绍两种方式的使用示例。

背景信息

本文中的命令，均可在Kibana控制台中执行。登录Kibana控制台的方法，请参见登录Kibana控制台。

方式一：上传同义词文件

前提条件：已上传同义词文件。具体操作，请参见上传同义词文件进行上传。

以下示例使用filter过滤器配置同义词，使用aliyun_synonyms.txt作为测试文件，内容为begin, start。

创建索引。

PUT /aliyun-index-test
{
  "settings": {
    "index":{
      "analysis": {
          "analyzer": {
            "by_smart": {
              "type": "custom",
              "tokenizer": "ik_smart",
              "filter": ["by_tfr","by_sfr"],
              "char_filter": ["by_cfr"]
            },
            "by_max_word": {
              "type": "custom",
              "tokenizer": "ik_max_word",
              "filter": ["by_tfr","by_sfr"],
              "char_filter": ["by_cfr"]
            }
         },
         "filter": {
            "by_tfr": {
              "type": "stop",
              "stopwords": [" "]
              },
           "by_sfr": {
              "type": "synonym",
              "synonyms_path": "analysis/aliyun_synonyms.txt"
              }
          },
          "char_filter": {
            "by_cfr": {
              "type": "mapping",
              "mappings": ["| => |"]
            }
          }
      }
    }
  }
}

配置同义词字段title。

Elasticsearch 7.0以下版本示例

PUT /aliyun-index-test/_mapping/doc
{
"properties": {
 "title": {
   "type": "text",
   "analyzer": "by_max_word",
   "search_analyzer": "by_smart"
 }
}
}

Elasticsearch 7.0及以上版本示例
```
PUT /aliyun-index-test/_mapping/
{
"properties": {
 "title": {
   "type": "text",
   "analyzer": "by_max_word",
   "search_analyzer": "by_smart"
 }
}
}
```
重要官方Elasticsearch从7.0版本开始，移除了类型（type）的概念，默认使用_doc代替。因此在设置索引mapping时无需指定type，否则会报错。

校验同义词。

GET /aliyun-index-test/_analyze
{
"analyzer": "by_smart",
"text":"begin"
}

执行成功后，返回如下结果。

{
"tokens": [
 {
   "token": "begin",
   "start_offset": 0,
   "end_offset": 5,
   "type": "ENGLISH",
   "position": 0
 },
 {
   "token": "start",
   "start_offset": 0,
   "end_offset": 5,
   "type": "SYNONYM",
   "position": 0
 }
]
}

添加数据，进行下一步测试。

Elasticsearch 7.0以下版本示例

PUT /aliyun-index-test/doc/1
{
"title": "Shall I begin?"
}

PUT /aliyun-index-test/doc/2
{
"title": "I start work at nine."
}

Elasticsearch 7.0及以上版本示例

PUT /aliyun-index-test/_doc/1
{
"title": "Shall I begin?"
}

PUT /aliyun-index-test/_doc/2
{
"title": "I start work at nine."
}

通过搜索测试，校验同义词。

GET /aliyun-index-test/_search
{
 "query" : { "match" : { "title" : "begin" }},
 "highlight" : {
     "pre_tags" : ["<red>", "<bule>"],
     "post_tags" : ["</red>", "</bule>"],
     "fields" : {
         "title" : {}
     }
 }
}

执行成功后，返回如下结果。

{
"took": 11,
"timed_out": false,
"_shards": {
 "total": 5,
 "successful": 5,
 "failed": 0
},
"hits": {
 "total": 2,
 "max_score": 0.41048482,
 "hits": [
   {
     "_index": "aliyun-index-test",
     "_type": "doc",
     "_id": "2",
     "_score": 0.41048482,
     "_source": {
       "title": "I start work at nine."
     },
     "highlight": {
       "title": [
         "I <red>start</red> work at nine."
       ]
     }
   },
   {
     "_index": "aliyun-index-test",
     "_type": "doc",
     "_id": "1",
     "_score": 0.39556286,
     "_source": {
       "title": "Shall I begin?"
     },
     "highlight": {
       "title": [
         "Shall I <red>begin</red>?"
       ]
     }
   }
 ]
}
}

方式二：直接引用同义词

以下示例直接引用同义词，并使用IK词典进行分词。

创建索引。

PUT /my_index
{
 "settings": {
     "analysis": {
         "analyzer": {
             "my_synonyms": {
                 "filter": [
                     "lowercase",
                     "my_synonym_filter"
                 ],
                 "tokenizer": "ik_smart"
             }
         },
         "filter": {
             "my_synonym_filter": {
                 "synonyms": [
                     "begin,start"
                 ],
                 "type": "synonym"
             }
         }
     }
 }
}

以上命令的原理为：

设置一个同义词过滤器my_synonym_filter，并配置同义词词库。
设置一个my_synonyms解释器，使用ik_smart分词。
经过ik_smart分词，把所有字母小写，并作为同义词处理。

配置同义词字段title。
- Elasticsearch 7.0以下版本示例
```
PUT /my_index/_mapping/doc
{
"properties": {
 "title": {
   "type": "text",
   "analyzer": "my_synonyms"
 }
}
}
```
- Elasticsearch 7.0及以上版本示例
```
PUT /my_index/_mapping/
{
"properties": {
 "title": {
   "type": "text",
   "analyzer": "my_synonyms"
 }
}
}
```
  重要官方Elasticsearch从7.0版本开始，移除了类型（type）的概念，默认使用_doc代替，所以在设置索引mapping时无需指定type，否则会报错。

校验同义词。

GET /my_index/_analyze
{
 "analyzer":"my_synonyms",
 "text":"Shall I begin?"
}

执行成功后，返回如下结果。

{
"tokens": [
 {
   "token": "shall",
   "start_offset": 0,
   "end_offset": 5,
   "type": "ENGLISH",
   "position": 0
 },
 {
   "token": "i",
   "start_offset": 6,
   "end_offset": 7,
   "type": "ENGLISH",
   "position": 1
 },
 {
   "token": "begin",
   "start_offset": 8,
   "end_offset": 13,
   "type": "ENGLISH",
   "position": 2
 },
 {
   "token": "start",
   "start_offset": 8,
   "end_offset": 13,
   "type": "SYNONYM",
   "position": 2
 }
]
}

添加数据，进行下一步测试。

Elasticsearch 7.0以下版本示例

PUT /my_index/doc/1
{
"title": "Shall I begin?"
}

PUT /my_index/doc/2
{
"title": "I start work at nine."
}

Elasticsearch 7.0及以上版本示例

PUT /my_index/_doc/1
{
"title": "Shall I begin?"
}

PUT /my_index/_doc/2
{
"title": "I start work at nine."
}

通过搜索测试，校验同义词。

GET /my_index/_search
{
"query" : { "match" : { "title" : "begin" }},
"highlight" : {
  "pre_tags" : ["<red>", "<bule>"],
  "post_tags" : ["</red>", "</bule>"],
  "fields" : {
      "title" : {}
  }
}
}

执行成功后，返回如下结果。

{
"took": 11,
"timed_out": false,
"_shards": {
 "total": 5,
 "successful": 5,
 "failed": 0
},
"hits": {
 "total": 2,
 "max_score": 0.41913947,
 "hits": [
   {
     "_index": "my_index",
     "_type": "doc",
     "_id": "2",
     "_score": 0.41913947,
     "_source": {
       "title": "I start work at nine."
     },
     "highlight": {
       "title": [
         "I <red>start</red> work at nine."
       ]
     }
   },
   {
     "_index": "my_index",
     "_type": "doc",
     "_id": "1",
     "_score": 0.39556286,
     "_source": {
       "title": "Shall I begin?"
     },
     "highlight": {
       "title": [
         "Shall I <red>begin</red>?"
       ]
     }
   }
 ]
}
}