Elasticsearch 关键字自动补全的实现

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我们经常能看到在各大电商网站搜索关键字的时候,底下下拉框会补全你要搜索的商品,或者类似的商品,有时候甚至连错别字也能纠正过来,其实ElasticSearch也能实现这样的功能

背景

我们经常能看到在各大电商网站搜索关键字的时候,底下下拉框会补全你要搜索的商品,或者类似的商品,有时候甚至连错别字也能纠正过来,其实ElasticSearch也能实现这样的功能

创建索引

首先,能够被自动补全的需要设置索引类型为”completion”,其次,还可以设置自动提示为中文分词

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{
  "settings": {
    "analysis": {
      "analyzer": {
        "ik": {
          "tokenizer": "ik_max_word"
        },
        "ngram_analyzer": {
          "tokenizer": "ngram_tokenizer"
        }
      },
      "tokenizer": {
        "ngram_tokenizer": {
          "type": "ngram",
          "min_gram": 1,
          "max_gram": 30,
          "token_chars": [
            "letter",
            "digit"
          ]
        }
      }
    }
  },
  "mappings": {
    "knowledge_info": {
      "properties": {
        "infoId": {
          "type": "string"
        },
        "infoTitle": {
          "type": "string",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word",
          "fields": {
            "suggest": {
              "max_input_length": 30,
              "preserve_position_increments": false,
              "type": "completion",
              "preserve_separators": false,
              "analyzer": "ik_max_word"
            },
            "wordCloud": {
              "type": "string",
              "analyzer": "ik_smart",
              "fielddata":"true"
            }
          }
        },
        "infoKeywords": {
          "type": "string",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word",
          "fields": {
            "suggest": {
              "max_input_length": 30,
              "preserve_position_increments": false,
              "type": "completion",
              "preserve_separators": false,
              "analyzer": "ik_max_word"
            },
            "wordCloud": {
              "type": "string",
              "analyzer": "ik_smart",
              "fielddata":"true"
            }
          }
        },
        "infoSummary": {
          "type": "string",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word",
          "fields": {
            "suggest": {
              "max_input_length": 30,
              "preserve_position_increments": false,
              "type": "completion",
              "preserve_separators": false,
              "analyzer": "ik_max_word"
            },
            "wordCloud": {
              "type": "string",
              "analyzer": "ik_smart",
              "fielddata":"true"
            }
          }
        },
        "infoContent": {
          "type": "text",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word"
        },
        "propertyAuthor": {
          "type": "string",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word"
        },
        "propertyIssueUnit": {
          "type": "string",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word"
        },
        "propertyStandardCode": {
          "type": "string",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word"
        },
        "propertyLiteratureCategory": {
          "type": "string",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word"
        },
        "propertyLcCode": {
          "type": "string",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word"
        },
        "propertyLiteratureCode": {
          "type": "string",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word"
        },
        "data": {
          "type": "text"
        },
        "attachment.content": {
          "type": "text",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word"
        },
        "auditState": {
          "type": "string"
        },
        "infoType": {
          "type": "string"
        },
        "infoFileUrl": {
          "type": "string"
        },
        "infoFileName": {
          "type": "string",
          "search_analyzer": "ik_max_word",
          "analyzer": "ik_max_word",
          "fields": {
            "suggest": {
              "max_input_length": 60,
              "preserve_position_increments": false,
              "type": "completion",
              "preserve_separators": false,
              "analyzer": "ik_max_word"
            }
          }
        },
        "createTime": {
          "type": "string"
        }
      }
    }
  }
}

其中 elasticsearch 需要安装中文分词 ik 插件和附件处理插件 ingest-attachment

Java API 调用

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/**
 * 自动完成提示
 * @param search search
 * @return MessageBody
 */
public MessageBody autoCompleteKnowledgeInfo(KnowledgeSearch search) {
    //设置搜索建议
    CompletionSuggestionBuilder infoTitleSuggestion = new CompletionSuggestionBuilder("infoTitle.suggest")
            .text(search.getQuery())
            .size(6);
    CompletionSuggestionBuilder infoKeywordsSuggestion = new CompletionSuggestionBuilder("infoKeywords.suggest")
            .text(search.getQuery())
            .size(6);
    CompletionSuggestionBuilder infoSummarySuggestion = new CompletionSuggestionBuilder("infoSummary.suggest")
            .text(search.getQuery())
            .size(6);
    CompletionSuggestionBuilder infoFileNameSuggestion = new CompletionSuggestionBuilder("infoFileName.suggest")
            .text(search.getQuery())
            .size(6);
    SuggestBuilder suggestBuilder = new SuggestBuilder()
            .addSuggestion("标题", infoTitleSuggestion)
            .addSuggestion("关键字", infoKeywordsSuggestion)
            .addSuggestion("摘要", infoSummarySuggestion)
            .addSuggestion("附件",infoFileNameSuggestion);
    SearchRequestBuilder searchRequest = client.prepareSearch(ES_KNOWLEDGE_INDEX)
            .setFetchSource(false)
            .suggest(suggestBuilder);
    List<JSONObject> list = new ArrayList<>();

    //查询结果
    SearchResponse searchResponse = searchRequest.get();

    /*没查到结果*/
    if (searchResponse.getSuggest() == null) {
        return MessageBody.success(list);
    }
    searchResponse.getSuggest().forEach(entries -> {
        String name = entries.getName();
        for (Suggest.Suggestion.Entry<? extends Suggest.Suggestion.Entry.Option> entry : entries) {
            for (Suggest.Suggestion.Entry.Option option : entry.getOptions()) {
                JSONObject object = new JSONObject();
                object.put("name",name);
                object.put("text",option.getText().string());
                list.add(object);
            }
        }
    });
    return MessageBody.success(list);
}

代码摘取自项目中的部分, 另外前端还可以配合自动完成的插件,最终来实现效果.