#首先我们还是先增加几个文档

PUT /myindex/article/1
{"post_date": "2020-03-14","title": "Java","content": "java is the best language","author_id": 119
}PUT /myindex/article/2
{"post_date": "2020-03-14" ,"title": "html","content": "I like html","author_id": 120
}
PUT /myindex/article/3
{"post_date": "2020-03-14" ,"title": "es","content": "Es is distributed document store" ,"author_id": 110
}

 

#查看es的文档映射mapping的数据结构
GET /myindex/article/_mapping

mapping数据结构如下： 

{"myindex" : {"mappings" : {"article" : {"properties" : {"author_ id" : {"type" : "long"},"content" : {"type" : "text","fields" : {"keyword" : {"type" : "keyword","ignore_above" : 256}}},"post_ _date" : {"type" : "date"},"post_ date" : {"type" : "text","fields" : {"keyword" : {"type" : "keyword","ignore_above" : 256}}},"title" : {"type" : "text","fields" : {"keyword" : {"type" : "keyword","ignore_above" : 256}}}}}}}
}

这里我们并没有为索引文档的数据结构做定义，但是我们发现es自动创建了 index type 以及type对应的mapping(dynamic mapping) 说明ElasticSearch能根据我们给的数据自动检测并且给定字段的数据类型

如果给定的  true  、false------>boolean

如果给定的字符串 "字符串"------>string（注意我这里用的是6.8.6版本 string已经被text或者keyword代替）

如果给定的数字   1、2------>long

如果给定的小数  12.34------>double

如果给定的时间   2020-03-14------->date

什么是映射mapping？

mapping定义了type中的每个字段的数据类型以及这些字段的如何分词的等相关属性

我们现在带查询一下添加的文档内容 GET /myindex/article/_search

{"took" : 29,"timed_out" : false,"_shards" : {"total" : 5,"successful" : 5,"skipped" : 0,"failed" : 0},"hits" : {"total" : 3,"max_score" : 1.0,"hits" : [{"_index" : "myindex","_type" : "article","_id" : "2","_score" : 1.0,"_source" : {"post_ date" : "2020-03-14","title" : "html","content" : "I like html","author_ id" : 120}},{"_index" : "myindex","_type" : "article","_id" : "1","_score" : 1.0,"_source" : {"post_ date" : "2020-03-14","title" : "Java","content" : "java is the best language","author_ id" : 119}},{"_index" : "myindex","_type" : "article","_id" : "3","_score" : 1.0,"_source" : {"post_ _date" : "2020-03-14","title" : "es","content" : "Es is distributed document store","author_ id" : 110}}]}
}

 

带条件的查询

#查不出来
GET /myindex/article/_search?q=post_date:2020

 

#可以查出来
GET /myindex/article/_search?q=post_date:2020-03-14

{"took" : 4,"timed_out" : false,"_shards" : {"total" : 5,"successful" : 5,"skipped" : 0,"failed" : 0},"hits" : {"total" : 3,"max_score" : 1.0,"hits" : [{"_index" : "myindex","_type" : "article","_id" : "2","_score" : 1.0,"_source" : {"post_date" : "2020-03-14","title" : "html","content" : "I like html","author_id" : 120}},{"_index" : "myindex","_type" : "article","_id" : "1","_score" : 1.0,"_source" : {"post_date" : "2020-03-14","title" : "Java","content" : "java is the best language","author_id" : 119}},{"_index" : "myindex","_type" : "article","_id" : "3","_score" : 1.0,"_source" : {"post_date" : "2020-03-14","title" : "es","content" : "Es is distributed document store","author_id" : 110}}]}
}

 

#可以查出来
GET /myindex/article/_search?q=content:html

 

 

注意？

这是因为ElasticSearch映射mapping进行指定的，post_date是日期类型，而content是字符串类型所以字符串就查询出来了。像日期date类型和数字long类型要进行精确查询才可以查询，而说明日期和数字类型没有进行分词，而字符串进行了分词。字符串text类型默认进行了分词的

 

到这里我们知道了mapping有两个作用，一是规定自定的类型，二是规定相关字段的属性（比如是不是进行分词）