阿里云Elasticsearch支持使用filter过滤器来配置同义词。filter过滤器支持Solr和WordNet两种同义词格式。本文介绍同义词词典的配置规则。

配置示例

PUT /test_index
{    
    "settings": {        
        "index" : {            
            "analysis" : {                
                "analyzer" : {                    
                    "synonym" : {                        
                        "tokenizer" : "whitespace",                       
                        "filter" : ["synonym"]                    
                        }               
                   },                
                   "filter" : {                    
                        "synonym" : {                       
                             "type" : "synonym",                        
                              "synonyms_path" : "analysis/synonym.txt",                                          
                              "tokenizer" : "whitespace"                    
                          }               
                       }            
                    }        
                  }    
          }
}

filter中配置了一个synonym（同义词）过滤器，其中包含了同义词词典文件的路径analysis/synonym.txt（路径是相对于config的位置）。更多参数说明请参见官方Synonym Token Filter文档。

Solr同义词

配置规则示例如下。 
# Blank lines and lines starting with pound are comments.
# Explicit mappings match any token sequence on the LHS of "=>"
# and replace with all alternatives on the RHS.  These types of mappings
# ignore the expand parameter in the schema.
# Examples:
i-pod, i pod => ipod,
sea biscuit, sea biscit => seabiscuit
# Equivalent synonyms may be separated with commas and give
# no explicit mapping.  In this case the mapping behavior will
# be taken from the expand parameter in the schema.  This allows
# the same synonym file to be used in different synonym handling strategies.
# Examples:
ipod, i-pod, i pod
foozball , foosball
universe , cosmos
lol, laughing out loud
# If expand==true, "ipod, i-pod, i pod" is equivalent
# to the explicit mapping:
ipod, i-pod, i pod => ipod, i-pod, i pod
# If expand==false, "ipod, i-pod, i pod" is equivalent
# to the explicit mapping:
ipod, i-pod, i pod => ipod
# Multiple synonym mapping entries are merged.
foo => foo bar
foo => baz
# is equivalent to
foo => foo bar, baz
您也可以在filter过滤器中直接定义同义词（请注意使用synonyms而不是synonyms_path），示例如下。 
PUT /test_index
{
    "settings": {
        "index" : {
            "analysis" : {
                "filter" : {
                    "synonym" : {
                        "type" : "synonym",
                        "synonyms" : [
                            "i-pod, i pod => ipod",
                            "begin, start"
                        ]
                    }
                }
            }
        }
    }
}
说明 建议您使用synonyms_path在文件中定义大型同义词集。

WordNet同义词

配置规则示例如下。 
PUT /test_index
{
    "settings": {
        "index" : {
            "analysis" : {
                "filter" : {
                    "synonym" : {
                        "type" : "synonym",
                        "format" : "wordnet",
                        "synonyms" : [
                            "s(100000001,1,'abstain',v,1,0).",
                            "s(100000001,2,'refrain',v,1,0).",
                            "s(100000001,3,'desist',v,1,0)."
                        ]
                    }
                }
            }
        }
    }
}

以上示例使用synonyms定义WordNet同义词，您也可以使用synonyms_path在文本中定义WordNet同义词。