Elasticsearch 實戰：基于 function_score 的搜索與權重排序

下面基于項目中關于律師筆記的es搜索功能開發，來記錄下es中基于 function_score 的搜索與權重排序在項目中是如何具體應用和實現的。

一、需求內容

項目中有一個功能，簡單描述為：全局搜索公開展示的律師筆記，通過輸入關鍵詞，匹配筆記標題，律師姓名、律所名稱、擅長領域這四個字段，排序規則：點贊數（由高到低）> 筆記發布時間（由近到遠）> 筆記ID（由大到小）

可以理解為：

搜索內容涉及：筆記標題（title 字段），作為最核心的匹配字段。

律師信息，包括律師姓名（nick_name）、律所名稱（law_firm）和擅長領域（good_at_topic）。這些字段也會影響匹配度，但權重較標題低。

排序優先級：

第一優先級：根據筆記的“點贊數”（like_count）倒序排列，點贊越多，排序越靠前。

第二優先級：在點贊數相同時，按筆記的“發布時間”（create_time）倒序排列，最新發布的筆記優先展示。

兜底排序規則：若上述條件均相同，則按 id 主鍵倒序排序。

二、需求分析

1. 擅長領域存入es的是id 數組，需要先通過分詞到主題 topic 索引中查詢匹配的id數組，再去筆記 note 索引中做筆記查詢

2. 使用 function_score 來給不同匹配條件設置不同權重，提高匹配精準度。（搜索字段的權重從高到低：標題 > 律師姓名 > 律所名稱 > 擅長領域

3. 通過 Elasticsearch 自帶的排序機制，實現基于 like_count、create_time 和 id 的多級排序。

4. 利用 filter 確保部分條件不影響打分，只作為過濾條件（例如筆記狀態必須為公開）。

三、Java代碼實現

技術背景：java 框架使用springboot 2.6, elasticsearch 8.15，es框架使用的是 easy-es 3.0.0

部分重要代碼示例：

四、DSL查詢示例

筆記 note 索引的Mapping定義：

PUT /note
{
   "settings": {
    "number_of_shards": 7,
    "index.max_ngram_diff": 2,
    "analysis": {
      "tokenizer": {
        "ik_smart_tokenizer": {
          "type": "ik_smart"
        },
        "ngram_tokenizer": {
          "type": "ngram",
          "min_gram": 2,
          "max_gram": 3
        }
      },
      "filter": {
        "ngram_filter": {
          "type": "ngram",
          "min_gram": 2,
          "max_gram": 3
        }
      },
      "analyzer": {
        "ik_ngram_analyzer": {
          "type": "custom",
          "tokenizer": "ik_smart_tokenizer",
          "filter": ["ngram_filter"]
        },
        "ngram_analyzer": {
          "type": "custom",
          "tokenizer": "ngram_tokenizer"
        }
      }
    }
  },
  "aliases": {
    "note_alias": {}
  },
  "mappings": {
    "properties": {
      "id": { "type": "keyword" },
      "lawyer_id": { "type": "keyword" },
      "name": { "type": "keyword"},
      "nick_name": { "type": "keyword"},
      "law_firm": { "type": "keyword"},
      "good_at_topic": { "type": "keyword" },
      "head_url": { "type": "keyword" },
      "title": { 
        "type": "text", 
        "analyzer": "ik_ngram_analyzer", 
        "fields": { 
          "keyword": { 
            "type": "keyword", 
            "ignore_above": 256 
          } 
        }
      },
      "cover": { "type": "keyword" },
      "description": { "type": "keyword"},
      "type": { "type": "keyword" },
      "content": { "type": "keyword" },
      "status": { "type": "keyword" },
      "top": { "type": "integer" },
      "top_time": { "type": "date", "format": "yyyy-MM-dd HH:mm:ss" },
      "like_count": { "type": "integer" },
      "comment_count": { "type": "integer" },
      "collect_count": { "type": "integer" },
      "share_count": { "type": "integer" },
      "look_count": { "type": "integer" },
      "create_time": { "type": "date", "format": "yyyy-MM-dd HH:mm:ss" },
      "create_by": { "type": "keyword" },
      "update_time": { "type": "date", "format": "yyyy-MM-dd HH:mm:ss" },
      "update_by": { "type": "keyword" },
      "version": { "type": "keyword" }
    }
  }
}

查詢DSL語句為：

GET /note/_search
{
  "from": 0,
  "query": {
    "bool": {
      "filter": [  // 不參與評分
        {
          "bool": {
            "must": [
              {
                "term": {
                  "status": {
                    "boost": 1,
                    "value": "PUBLIC"
                  }
                }
              }
            ]
          }
        }
      ],
      "must": [
        {
          "function_score": {
            "boost_mode": "multiply",
            "functions": [
              {
                "filter": {
                  "match": {
                    "title": {
                      "query": "測試"
                    }
                  }
                },
                "weight": 10000
              },
              {
                "filter": {
                  "wildcard": {
                    "nick_name": {
                      "value": "*測試*"
                    }
                  }
                },
                "weight": 1000
              },
              {
                "filter": {
                  "wildcard": {
                    "law_firm": {
                      "value": "*測試*"
                    }
                  }
                },
                "weight": 100
              },
              {
                "filter": {
                  "terms": {
                    "good_at_topic": []
                  }
                },
                "weight": 10
              }
            ],
            "min_score": 10,
            "score_mode": "sum"
          }
        }
      ]
    }
  },
  "size": 10,
  "sort": [
    {
      "_score": {
        "order": "desc"
      }
    },
    {
      "like_count": {
        "order": "desc"
      }
    },
    {
      "create_time": {
        "order": "desc"
      }
    },
    {
      "id": {
        "order": "desc"
      }
    }
  ],
  "track_total_hits": true
}

查詢結果部分內容為：

{
  "took": 5,
  "timed_out": false,
  "_shards": {
    "total": 7,
    "successful": 7,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 136,
    "max_score": null,
    "hits": [
     {
        "_index": "note",
        "_id": "1952978126582046720",
        "_score": 10100,
        "_source": {
          "id": "1952978126582046720",
          "law_firm": "測試授權企業",
          "nick_name": "王五",
          "title": "測試筆記",
          "like_count": 3,
          "create_time": "2025-08-06 14:20:45"
        },
        "sort": [
          10100,
          2,
          1754490045000,
          "1952978126582046720"
        ]
      },
      {
        "_index": "note",
        "_id": "1896834568167723008",
        "_score": 10100,
        "_source": {
          "id": "1896834568167723008",
          "law_firm": "測試簽約12",
          "nick_name": "李六",
          "title": "805筆記測試",
          "like_count": 2,
          "create_time": "2025-03-04 16:06:17"
        },
        "sort": [
          10000,
          8,
          1741104377000,
          "1896834568167723008"
        ]
      },
      {
        "_index": "note",
        "_id": "1912125735872598016",
        "_score": 10000,
        "_source": {
          "id": "1912125735872598016",
          "law_firm": "袁向何律師事務所",
          "nick_name": "歡樂豆0905",
          "title": "測試一下",
          "like_count": 5,
          "create_time": "2025-04-15 20:47:56"
        },
        "sort": [
          10000,
          5,
          1744750076000,
          "1912125735872598016"
        ]
      }
    ]
  }
}

posted @ 2025-09-16 16:02 歡樂豆123 閱讀(43) 評論(0) 收藏舉報

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Elasticsearch 實戰：基于 function_score 的搜索與權重排序

Elasticsearch 實戰：基于 function_score 的搜索與權重排序

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