Elasticsearch结合IK分词器：如何保留含特殊字符的完整分词？

可以通过自定义分析器+字符过滤器+IK分词器的组合实现需求，具体步骤如下：

1. 配置自定义字符过滤器，锁定需完整保留的特殊字符串 #

创建mapping类型的字符过滤器，将foo(bar)这类目标字符串替换为临时标记（避免被IK分词器拆分），后续再还原：

{
  "settings": {
    "analysis": {
      "char_filter": {
        "mark_special_str": {
          "type": "mapping",
          "mappings": [
            "foo(bar) => _foo_bar_"
          ]
        },
        "restore_special_str": {
          "type": "mapping",
          "mappings": [
            "_foo_bar_ => foo(bar)"
          ]
        }
      }
    }
  }
}

2. 组合字符过滤器与IK分词器，构建自定义分析器 #

将上述字符过滤器与ik_smart分词器结合，同时加入同义词过滤器（如果需要）：

{
  "settings": {
    "analysis": {
      "char_filter": {
        "mark_special_str": {
          "type": "mapping",
          "mappings": [
            "foo(bar) => _foo_bar_"
          ]
        },
        "restore_special_str": {
          "type": "mapping",
          "mappings": [
            "_foo_bar_ => foo(bar)"
          ]
        }
      },
      "filter": {
        "custom_synonym": {
          "type": "synonym",
          "synonyms": [
            "abc => _foo_bar_"
          ]
        }
      },
      "analyzer": {
        "custom_ik": {
          "type": "custom",
          "char_filter": ["mark_special_str"],
          "tokenizer": "ik_smart",
          "filter": ["lowercase", "custom_synonym", "restore_special_str"]
        }
      }
    }
  },
  "mappings": {
    "properties": {
      "name": {
        "type": "text",
        "analyzer": "custom_ik",
        "fields": {
          "keyword": {
            "type": "keyword"
          }
        }
      }
    }
  }
}

3. 验证效果 #

• 输入i want a foo(bar)时，会保留完整的foo(bar)分词；中文弹性搜索很厉害会被正确拆分为['弹性', '搜索', '很', '厉害']
• 搜索abc时，同义词转换为临时标记_foo_bar_，经IK分词后保留完整标记，最终还原为foo(bar)，实现精确匹配

内容的提问来源于stack exchange，提问作者chouyangv3