使用HanLP增强Elasticsearch分词功能

hanlp-ext 插件源码地址：http://git.oschina.net/hualongdata/hanlp-ext 或 https://github.com/hualongdata/hanlp-ext

Elasticsearch 默认对中文分词是按“字”进行分词的，这是肯定不能达到我们进行分词搜索的要求的。官方有一个 SmartCN 中文分词插件，另外还有一个 IK 分词插件使用也比较广。但这里，我们采用 HanLP 这款 自然语言处理工具 来进行中文分词。

Elasticsearch
Elasticsearch 的默认分词效果是惨不忍睹的。

GET /_analyze?pretty { "text" : ["重庆华龙网海数科技有限公司"] }

输出：

{
"tokens": [

{ "token": "重", "start_offset": 0, "end_offset": 1, "type": "<IDEOGRAPHIC>", "position": 0 }, { "token": "庆", "start_offset": 1, "end_offset": 2, "type": "<IDEOGRAPHIC>", "position": 1 }, { "token": "华", "start_offset": 2, "end_offset": 3, "type": "<IDEOGRAPHIC>", "position": 2 }, { "token": "龙", "start_offset": 3, "end_offset": 4, "type": "<IDEOGRAPHIC>", "position": 3 }, { "token": "网", "start_offset": 4, "end_offset": 5, "type": "<IDEOGRAPHIC>", "position": 4 }, { "token": "海", "start_offset": 5, "end_offset": 6, "type": "<IDEOGRAPHIC>", "position": 5 }, { "token": "数", "start_offset": 6, "end_offset": 7, "type": "<IDEOGRAPHIC>", "position": 6 }, { "token": "科", "start_offset": 7, "end_offset": 8, "type": "<IDEOGRAPHIC>", "position": 7 }, { "token": "技", "start_offset": 8, "end_offset": 9, "type": "<IDEOGRAPHIC>", "position": 8 }, { "token": "有", "start_offset": 9, "end_offset": 10, "type": "<IDEOGRAPHIC>", "position": 9 }, { "token": "限", "start_offset": 10, "end_offset": 11, "type": "<IDEOGRAPHIC>", "position": 10 }, { "token": "公", "start_offset": 11, "end_offset": 12, "type": "<IDEOGRAPHIC>", "position": 11 }, { "token": "司", "start_offset": 12, "end_offset": 13, "type": "<IDEOGRAPHIC>", "position": 12 }

]
}
可以看到，默认是按字进行分词的。

elasticsearch-hanlp
HanLP

HanLP 是一款使用 Java 实现的优秀的，具有如下功能：

中文分词
词性标注
命名实体识别
关键词提取
自动摘要
短语提取
拼音转换
简繁转换
文本推荐
依存句法分析
语料库工具
安装 elasticsearch-hanlp（安装见：https://github.com/hualongdata/hanlp-ext/tree/master/es-plugin）插件以后，我们再来看看分词效果。

GET /_analyze?pretty { "analyzer" : "hanlp", "text" : ["重庆华龙网海数科技有限公司"] }

输出：

{
"tokens": [

{ "token": "重庆", "start_offset": 0, "end_offset": 2, "type": "ns", "position": 0 }, { "token": "华龙网", "start_offset": 2, "end_offset": 5, "type": "nr", "position": 1 }, { "token": "海数", "start_offset": 5, "end_offset": 7, "type": "nr", "position": 2 }, { "token": "科技", "start_offset": 7, "end_offset": 9, "type": "n", "position": 3 }, { "token": "有限公司", "start_offset": 9, "end_offset": 13, "type": "nis", "position": 4 }

]
}
HanLP 的功能不止简单的中文分词，有很多功能都可以集成到 Elasticsearch 中。

文章来源于羊八井的博客