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
