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