elasticsearch学习笔记（六）——快速入门案例实战之电商网站商品管理：多种搜索方式

简单介绍一下ES的多种搜索方式

1、query string search

格式：

GET /{index}/_search

GET /product/_search
{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "product",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "name" : "jiajieshi yagao",
          "desc" : "youxiao fangzhu",
          "price" : 25,
          "producer" : "jiajieshi producer",
          "tags" : [
            "fangzhu"
          ]
        }
      },
      {
        "_index" : "product",
        "_type" : "_doc",
        "_id" : "3",
        "_score" : 1.0,
        "_source" : {
          "name" : "zhonghua yagao",
          "desc" : "caoben zhiwu",
          "price" : 40,
          "producer" : "zhonghua producer",
          "tags" : [
            "qingxin"
          ]
        }
      }
    ]
  }
}

简单见一下查询结果的各个值的含义：
took:耗费的时间 单位是毫秒
timed_out:是否超时
_shards: total是指打到的primary shard(或者replica shard)的个数，successful是指查询成功的分片数，skipped是指跳过的分片个数，failed是指查询失败的分片的个数
hits.total:value代表查询匹配的总数，relation代表The count is accurate (e.g. "eq" means equals).
hits.max_score:是指匹配的文档中相关度分数最高的
hits.hits:包含匹配搜索的document的详细数据

为什么叫做query string search ,主要是因为search参数都是以http请求的query string来附带的
例如搜索商品名称中包含yagao的商品，而且按照售价降序排列：

GET /product/_search?q=name:yagao&sort=price:desc
{
  "took" : 36,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [
      {
        "_index" : "product",
        "_type" : "_doc",
        "_id" : "3",
        "_score" : null,
        "_source" : {
          "name" : "zhonghua yagao",
          "desc" : "caoben zhiwu",
          "price" : 40,
          "producer" : "zhonghua producer",
          "tags" : [
            "qingxin"
          ]
        },
        "sort" : [
          40
        ]
      },
      {
        "_index" : "product",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : null,
        "_source" : {
          "name" : "jiajieshi yagao",
          "desc" : "youxiao fangzhu",
          "price" : 25,
          "producer" : "jiajieshi producer",
          "tags" : [
            "fangzhu"
          ]
        },
        "sort" : [
          25
        ]
      }
    ]
  }
}

query string search适用于临时的在命令行使用的一些工具，比如curl,快速发出请求，来检索想要的信息。但是如果查询请求很复杂，就很难去构建搜索条件，在生产环境中很少使用。

2、query DSL

什么叫做DSL？
DSL：Domain Specified Language 特定领域语言
使用query DSL 查询时查询的参数采用的是请求体（http request body），可以用json的格式来构建查询语法，比较方便，可以构建各种复杂的语法。比query string search 肯定是强大多了
格式：

GET /{index}/{type}/_search
{
    "json数据"
}

下面都是实际的一些例子：
查询所有的商品:

GET /product/_search
{
  "query": {
    "match_all": {}
  }
}

查询名称中包含yagao的商品，同时按照价格降序排序：

GET /product/_search
{
  "query": {
    "match": {
      "name": "yagao"
    }
  },
  "sort": [
    {
      "price": {
        "order": "desc"
      }
    }
  ]
}

分页查询商品，总共3个商品，假设每一页就显示1条商品，现在显示第2页，所以就查出来第2个商品

GET /product/_search
{
  "query": {
    "match_all": {}
  },
  "from": 1, 
  "size": 1
}

指定要查询出来的商品只返回名称和价格，也就是定制返回字段

GET /product/_search
{
  "query": {
    "match_all": {}
  },
  "_source": ["name", "price"]
}

query DSL 更加适合生产环境使用，可以构建复杂的查询

3、query filter

搜索商品名称包含yagao，而且售价大于25元的商品

GET /product/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "name": "yagao"
          }
        }
      ],
      "filter": {
        "range": {
          "price": {
            "gt": 25
          }
        }
      }
    }
  }
}

4、full-text search

GET /product/_search
{
  "query": {
    "match": {
      "producer": "jiajieshi producer"
    }
  }
}
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : 0.18232156,
    "hits" : [
      {
        "_index" : "product",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 0.18232156,
        "_source" : {
          "name" : "jiajieshi yagao",
          "desc" : "youxiao fangzhu",
          "price" : 25,
          "producer" : "jiajieshi producer",
          "tags" : [
            "fangzhu"
          ]
        }
      },
      {
        "_index" : "product",
        "_type" : "_doc",
        "_id" : "3",
        "_score" : 0.18232156,
        "_source" : {
          "name" : "zhonghua yagao",
          "desc" : "caoben zhiwu",
          "price" : 40,
          "producer" : "zhonghua producer",
          "tags" : [
            "qingxin"
          ]
        }
      }
    ]
  }
}

为什么连zhonghua producer这个文档也被检索出来了，原因是producer这个字段一开始插入数据的时候，就会被拆解，建立倒排索引
jiajieshi 1
zhonghua 2
producer 1,2
搜索yagao producer的时候，会进行拆分变成yagao和producer

5、phrase search短语搜索

phrase search 跟全文检索相反，全文检索会将输入的搜索串拆解开来，去倒排索引里面一一去匹配，只要能匹配上任意一个拆解后的单词，就可以作为结果返回。但是phrase search要求输入的搜索串，必须在指定的字段文本中，完全包含一模一样的，才可以算匹配上了，作为结果返回。

GET /product/_search
{
  "query": {
    "match_phrase": {
      "producer": "jiajieshi producer"
    }
  }
}
{
  "took" : 4,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 0.87546873,
    "hits" : [
      {
        "_index" : "product",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 0.87546873,
        "_source" : {
          "name" : "jiajieshi yagao",
          "desc" : "youxiao fangzhu",
          "price" : 25,
          "producer" : "jiajieshi producer",
          "tags" : [
            "fangzhu"
          ]
        }
      }
    ]
  }
}

6、highlight search高亮搜索

GET /product/_search
{
  "query": {
    "match_phrase": {
      "producer": "jiajieshi producer"
    }
  },
  "highlight": {
    "fields": {
      "producer":{}
    }
  }
}
{
  "took" : 23,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 0.87546873,
    "hits" : [
      {
        "_index" : "product",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 0.87546873,
        "_source" : {
          "name" : "jiajieshi yagao",
          "desc" : "youxiao fangzhu",
          "price" : 25,
          "producer" : "jiajieshi producer",
          "tags" : [
            "fangzhu"
          ]
        },
        "highlight" : {
          "producer" : [
            "<em>jiajieshi</em> <em>producer</em>"
          ]
        }
      }
    ]
  }
}