IK Analysis for ElasticSearch

更新说明：对于使用es集群，用ik作为分词插件，经常会修改自定义词典，增加远程加载，每次更新都会重新加载词典，不必重启es服务。

The IK Analysis plugin integrates Lucene IK analyzer into elasticsearch, support customized dictionary.

Tokenizer: ik

Version

master | 1.5.0 -> master 1.4.0 | 1.6.0 1.3.0 | 1.5.0 1.2.9 | 1.4.0 1.2.8 | 1.3.2 1.2.7 | 1.2.1 1.2.6 | 1.0.0 1.2.5 | 0.90.2 1.2.3 | 0.90.2 1.2.0 | 0.90.0 1.1.3 | 0.20.2 1.1.2 | 0.19.x 1.0.0 | 0.16.2 -> 0.19.0

Thanks

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Install

you can download this plugin from RTF project(https://github.com/medcl/elasticsearch-rtf) https://github.com/medcl/elasticsearch-rtf/tree/master/plugins/analysis-ik https://github.com/medcl/elasticsearch-rtf/tree/master/config/ik

~~also remember to download the dict files,unzip these dict file into your elasticsearch's config folder,such as: your-es-root/config/ik~~

you need a service restart after that!

Dict Configuration (es-root/config/ik/IKAnalyzer.cfg.xml)

https://github.com/medcl/elasticsearch-analysis-ik/blob/master/config/ik/IKAnalyzer.cfg.xml

  
  
	IK Analyzer 扩展配置
	
	custom/mydict.dic;custom/single_word_low_freq.dic 	
	 
	custom/ext_stopword.dic 
 	
	location 
 	
	location

Analysis Configuration (elasticsearch.yml)

index:
  analysis:                   
    analyzer:      
      ik:
          alias: [ik_analyzer]
          type: org.elasticsearch.index.analysis.IkAnalyzerProvider
      ik_max_word:
          type: ik
          use_smart: false
      ik_smart:
          type: ik
          use_smart: true

index.analysis.analyzer.ik.type : "ik"

you can set your prefer segment mode,default use_smart is false.

Mapping Configuration

Here is a quick example: 1.create a index

curl -XPUT http://localhost:9200/index

2.create a mapping

curl -XPOST http://localhost:9200/index/fulltext/_mapping -d'
{
    "fulltext": {
             "_all": {
            "indexAnalyzer": "ik",
            "searchAnalyzer": "ik",
            "term_vector": "no",
            "store": "false"
        },
        "properties": {
            "content": {
                "type": "string",
                "store": "no",
                "term_vector": "with_positions_offsets",
                "indexAnalyzer": "ik",
                "searchAnalyzer": "ik",
                "include_in_all": "true",
                "boost": 8
            }
        }
    }
}'

3.index some docs

curl -XPOST http://localhost:9200/index/fulltext/1 -d'
{"content":"美国留给伊拉克的是个烂摊子吗"}
'

curl -XPOST http://localhost:9200/index/fulltext/2 -d'
{"content":"公安部：各地校车将享最高路权"}
'

curl -XPOST http://localhost:9200/index/fulltext/3 -d'
{"content":"中韩渔警冲突调查：韩警平均每天扣1艘**渔船"}
'

curl -XPOST http://localhost:9200/index/fulltext/4 -d'
{"content":"**驻洛杉矶领事馆遭亚裔男子枪击 嫌犯已自首"}
'

4.query with highlighting

curl -XPOST http://localhost:9200/index/fulltext/_search  -d'
{
    "query" : { "term" : { "content" : "**" }},
    "highlight" : {
        "pre_tags" : ["", ""],
        "post_tags" : ["", ""],
        "fields" : {
            "content" : {}
        }
    }
}
'

here is the query result

{
    "took": 14,
    "timed_out": false,
    "_shards": {
        "total": 5,
        "successful": 5,
        "failed": 0
    },
    "hits": {
        "total": 2,
        "max_score": 2,
        "hits": [
            {
                "_index": "index",
                "_type": "fulltext",
                "_id": "4",
                "_score": 2,
                "_source": {
                    "content": "**驻洛杉矶领事馆遭亚裔男子枪击 嫌犯已自首"
                },
                "highlight": {
                    "content": [
                        "**驻洛杉矶领事馆遭亚裔男子枪击 嫌犯已自首 "
                    ]
                }
            },
            {
                "_index": "index",
                "_type": "fulltext",
                "_id": "3",
                "_score": 2,
                "_source": {
                    "content": "中韩渔警冲突调查：韩警平均每天扣1艘**渔船"
                },
                "highlight": {
                    "content": [
                        "均每天扣1艘**渔船 "
                    ]
                }
            }
        ]
    }
}

have fun.

热更新IK分词使用方法

目前该插件支持热更新 ik 分词，通过上文在 ik 配置文件中提到的如下配置

 	
	location
 	
	location

其中 location 是指一个 url，比如 http://yoursite.com/getCustomDict，该请求只需满足一下两点即可完成分词热更新。

该 http 请求需要返回两个头部，一个是 Last-Modified，一个是 ETags，这两者都是字符串类型，只要有一个发生变化，该插件就会去抓取新的分词进而更新词库。
该 http 请求返回的内容格式是一行一个分词，换行符用 \n 即可。

满足上面两点要求就可以实现热更新分词了，不需要重启 es 实例。

常见问题：

1.自定义词典为什么没有生效？请确保你的扩展词典的文本格式为 UTF8 编码

2.如何手动安装，以 1.3.0 為例？（参考：https://github.com/medcl/elasticsearch-analysis-ik/issues/46）

git clone https://github.com/medcl/elasticsearch-analysis-ik cd elasticsearch-analysis-ik mvn compile mvn package plugin --install analysis-ik --url file:///#{project_path}/elasticsearch-analysis-ik/target/releases/elasticsearch-analysis-ik-1.3.0.zip

wadekun / elasticsearch-analysis-ik