ubuntu 下使用 elasticsearch5 同义词

2020-06-13 原文

1. 安装最新版 elasticsearch

参考:https://www.elastic.co/guide/en/elasticsearch/reference/5.2/deb.html

依次执行以下命令

wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -

sudo apt-get install apt-transport-https

echo "deb https://artifacts.elastic.co/packages/5.x/apt stable main" | sudo tee -a /etc/apt/sources.list.d/elastic-5.x.list

sudo apt-get update && sudo apt-get install elasticsearch

查看自己系统用的是 SysV 还是 systemd

ps -p 1

我用的是systemd 执行

sudo /bin/systemctl daemon-reload
sudo /bin/systemctl enable elasticsearch.service

2. 启动elasticsearch

sudo service elasticsearch start

3. 检查是否安装成功

curl -XGET 'localhost:9200/?pretty'

如果返回结果类似以下内容,说明安装成功

{
  "name" : "Cp8oag6","cluster_name" : "elasticsearch","cluster_uuid" : "AT69_T_DTp-1qgIJlatQqA","version" : {
    "number" : "5.2.2","build_hash" : "f27399d","build_date" : "2016-03-30T09:51:41.449Z","build_snapshot" : false,"lucene_version" : "6.4.1"
  },"tagline" : "You KNow,for Search"
}

4. 配置同义词

elasticsearch5 的默认目录是/etc/elasticsearch,所以在/etc/elasticsearch 目录下创建同义词文件

edit /etc/elasticsearch/analysis/synonyms.txt

输入同义词(每行一组),注意文件必须要是 utf-8 格式,英文逗号

中文,汉语,汉字,2室1厅1卫,2室2厅1卫=>二居室,1室1厅1卫=>一居室,一室
3室2厅1卫,三居室,

其中包含 => 的同义词是在analysis 时只生成 => 后面的词,应该比较省内存,不知道缺点是什么.

5. 安装分词插件

elasticsearch 默认是没有汉语词组的,所以要用这个插件

https://github.com/medcl/elasticsearch-analysis-ik/releases

下载和elasticsearch 匹配的版本,解压缩到elasticsearch 的 plugins 目录下的 ik 文件夹中,比如我的是/usr/share/elasticsearch/plugins/ik

6. 配置自定义词组

我们用到的词语有些是 ik 中已有的,比如中文/汉语/汉字,有些是没有的,比如一居室/二居室,没有的就要自己配置了

gedit /usr/share/elasticsearch/plugins/ik/config/custom/mydict.dic

添加自定义词组到文件中

2室1厅1卫
2室2厅1卫
二居室
1室1厅1卫
一居室
3室2厅1卫
三居室

安装/修改插件,需要重启elasticsearch 才会生效

sudo service elasticsearch stop
sudo service elasticsearch start

7. 检测自定义分词是否有效

curl -XGET 'http://localhost:9200/gj/_analyze?pretty&analyzer=by_smart' -d '{"text":"一居室"}

8. 创建 index

准备工作已经做好了,现在可以在代码中使用同义词了,这里用 PHP 演示一下

$client = ClientBuilder::create()->build();

        // 创建 index
        $settings = json_decode('{
            "analysis": {
                "analyzer": {
                    "by_smart": {
                        "type": "custom","tokenizer": "ik_smart","filter": [
                            "by_tfr","by_sfr"
                        ],"char_filter": [
                            "by_cfr"
                        ]
                    },"by_max_word": {
                        "type": "custom","tokenizer": "ik_max_word","char_filter": [
                            "by_cfr"
                        ]
                      }
                    },"filter": {
                        "by_tfr": {
                            "type": "stop","stopwords": [
                                " "
                            ]
                        },"by_sfr": {
                            "type": "synonym","synonyms_path": "analysis/synonyms.txt"
                        }
                    },"char_filter": {
                        "by_cfr": {
                            "type": "mapping","mappings": [
                                "| => |"
                            ]
                        }
                    }
                }
            }');

        $mappings = json_decode('{
            "_default_":{
              "properties": {
                  "shoujia": {
                    "type":"double"
                  }
              }
            },"xinfang":{
              "_source":{
                "enabled":true
              },"properties":{
                  "huxing": {
                      "type": "text","index": "analyzed","analyzer": "by_max_word","search_analyzer": "by_smart"
                  }
              }
            }
        }');

        $params = [
          'index'=>'gj','body'=>[
            'settings'=>$settings,'mappings'=>$mappings
          ]
        ];
        $client->indices()->create($params);

8. 名词解释

只用了几天elasticsearch,懂的地方不多,所以这些只是片面的理解.

_index 类似数据库中的 schema 名字

_type 类似数据表

properties 表中的字段

mappings 配置字段的分词规则(比如我们的ik分词),类型(integer,double,string,text等等)

analysis 分词的规则