ElasticSearch Snowball token filter

Snowball token filter

使用除梗器,对单词进行除梗的过滤器。语言参数可以控制除梗器，有如下的语言可供选择：
Armenian, Basque, Catalan, Danish, Dutch, English, Finnish, French, German, German2, Hungarian, Italian, Kp, Lithuanian, Lovins, Norwegian, Porter, Portuguese, Romanian, Russian, Spanish, Swedish, Turkish.

例如:

PUT /my_index
{
    "settings": {
        "analysis" : {
            "analyzer" : {
                "my_analyzer" : {
                    "tokenizer" : "standard",
                    "filter" : ["lowercase", "my_snow"]
                }
            },
            "filter" : {
                "my_snow" : {
                    "type" : "snowball",
                    "language" : "Lovins"
                }
            }
        }
    }
}

snowball token filter ，它可以把 sing/ sings / singing 都转化词干 sing。不管用户搜 sing、sings、singing， 他的搜索结果都是基于「sing」这个term，所得的结果集都一样。