如何在 elasticsearch 中结合模式分析器和 char_filter

Question

我有一个要标记化的关键字字段（以逗号分隔），但它也可能包含带有“+”字符的值。例如：

query_string.keywords = Living,Music,+concerts+and+live+bands,News,Portland

创建索引时，以下内容可以很好地以逗号分隔关键字：

{
    "settings": {
        "number_of_shards": 5,
        "analysis": {
            "analyzer": {
                "happy_tokens": {
                    "type":      "pattern",
                    "pattern":   "([,]+)"
                }
            }
        }
    },
    "mappings": {
        "post" : {
            "properties" : {
                "query_string.keywords" : {
                    "type": "string",
                    "analyzer" : "happy_tokens"
                }
            }
        }
    }
}

如何向其中添加 char_filter（见下文）以将 + 更改为空格或空字符串？

        "char_filter": {
            "kill_pluses": {
                "type": "pattern_replace",
                "pattern": "+",
                "replace": ""
            }
        }

Answer 1

您需要转义“+”，因为“+”在正则表达式中有一个 special meaning。

    "char_filter": {
        "kill_pluses": {
            "type": "pattern_replace",
            "pattern": "\+",
            "replace": ""
        }
    }

Answer 2

我发现 "mapping" char_filter 可以将我的加号转换为 space。标记化后，我能够 trim 标记删除白色 space。

custom analyzers page in the elasticsearch guide帮了大忙。

我的工作示例如下：

{
    "settings": {
        "number_of_shards": 5,
        "index": {
            "analysis": {
                "char_filter": {
                    "plus_to_space": {
                        "type": "mapping",
                        "mappings": ["+=>\u0020"]
                    }
                },
                "tokenizer": {
                    "split_on_comma": {
                        "type": "pattern",
                        "pattern": "([,]+)"
                    }
                },
                "analyzer": {
                    "happy_tokens": {
                        "type": "custom",
                        "char_filter": ["plus_to_space"],
                        "tokenizer": "split_on_comma",
                        "filter": ["trim"]
                    }
                }
            }
        }
    },
    "mappings": {
        "post" : {
            "properties" : {
                "query_string.keywords" : {
                    "type": "string",
                    "analyzer" : "happy_tokens"
                }
            }
        }
    }
}

如何在 elasticsearch 中结合模式分析器和 char_filter

How to combine a pattern analyzer and char_filter in elasticsearch

elasticsearch