elasticsearch API 学习

系统信息相关API

// 查看ec版本配置信息
http://localhost:9200
// 查看所有插件
http://localhost:9200/_cat/plugins?v
// 查看所有索引
http://localhost:9200/_cat/indices?v
// 对ES进行健康检查
http://localhost:9200/_cat/health?v
// 查看当前的磁盘占用率
http://localhost:9200/_cat/allocation?v

创建索引 yii2blog/articles

curl -v -X PUT "http://localhost:9200/yii2blog?pretty=true" -d "json"
curl -v -X POST "http://localhost:9200/yii2blog?pretty=true" -d "json"
{
    "settings":{
        "refresh_interval": "5s", //5秒后刷新
        "number_of_shards": 1,    //分片，目前1台机器，所以为1
        "number_of_replicas": 0   //副本为0
    },
    "mappings": {
        "_default_": {
            "_all": {
                "enabled": true   //所有数据都索引
            }
        },
        "articles": {             //名称可自定义，可定义为表名
            "dynamic": false ,    //动态映射
            "properties": {
                "article_id": {
                    "type": "long"
                },
                "post_title": {
                    "type": "string",
                    "index": "analyzed",
                    "analyzer": "ik"
                },
                "post_excerpt": {
                    "type": "string",
                    "index": "analyzed",
                    "analyzer": "ik"
                }
            }
        }
    }
}

删除索引 yii2blog/articles

curl -v -X DELETE "localhost:9200/yii2blog?pretty=true"

添加记录

curl -v X PUT "http://localhost:9200/yii2blog/articles/1?pretty=true" -d "json"
curl -v X POST "http://localhost:9200/yii2blog/articles/1?pretty=true" -d "json"
{
    "article_id" : 1,
    "post_title" : "这是文章标题",
    "post_excerpt" : "这是文章描述"
}

查看记录

curl -v X GET "http://localhost:9200/yii2blog/articles/1?pretty=true"

删除记录

curl -v X DELETE "http://localhost:9200/yii2blog/articles/1?pretty=true"

更新记录

curl -v X PUT "http://localhost:9200/yii2blog/articles/1?pretty=true" -d "json"
curl -v X POST "http://localhost:9200/yii2blog/articles/1?pretty=true" -d "json"
{
    "article_id" : 1,
    "post_title" : "更新文章标题",
    "post_excerpt" : "更新文章描述"
}

数据查询

1. 返回 elastic 中所有记录

curl -v X GET "http://localhost:9200/_search?pretty=true"

2. 返回 yii2blog 中所有记录

curl -v X GET "http://localhost:9200/yii2blog/_search?pretty=true"

3. 返回 yii2blog/articles 中所有记录

curl -v X GET "http://localhost:9200/yii2blog/articles/_search?pretty=true"

全文搜索

1. 使用 Match 查询，指定的匹配条件是 post_excerpt 字段里面包含"描述"这个词

curl -v X POST "http://localhost:9200/yii2blog/articles/_search?pretty=true" -d "json"
{
  "query" : { "match" : { "post_excerpt" : "描述" }}
}

2. 返回2两条记录（Elastic 默认一次返回10条结果）

curl -v X POST "http://localhost:9200/yii2blog/articles/_search?pretty=true" -d "json"
{
  "query" : { "match" : { "post_excerpt" : "描述" }},
  "size": 2
}

3. 从位置3开始（默认是从位置0开始），只返回5条结果。

curl -v X POST "http://localhost:9200/yii2blog/articles/_search?pretty=true" -d "json"
{
  "query" : { "match" : { "post_excerpt" : "描述" }},
  "from": 3,
  "size": 5
}

4. 搜索的是 "描述" or "文章"。

curl -v X POST "http://localhost:9200/yii2blog/articles/_search?pretty=true" -d "json"
{
  "query" : { "match" : { "post_excerpt" : "描述 文章" }}
}

5. 搜索的是 "描述" and "文章"，必须使用布尔查询。

curl -v X POST "http://localhost:9200/yii2blog/articles/_search?pretty=true" -d "json"
{
    "query": {
        "bool": {
            "must": [
                { "match": { "post_excerpt": "描述" } },
                { "match": { "post_excerpt": "文章" } }
            ]
        }
    }
}

6. 使用 Match 查询，指定的匹配条件是 post_excerpt 字段里面包含带高亮的"描述"这个词

curl -v X POST "http://localhost:9200/yii2blog/articles/_search?pretty=true" -d "json"
{
  "query": {
    "multi_match": {
      "query": "描述",
      "fields": [
        "post_excerpt"
      ]
    }
  },
  "highlight": {
    "pre_tags": [
      ""
    ],
    "post_tags": [
      ""
    ],
    "fields": {
      "post_excerpt": {}
    }
  }
}

结果：

{
    "took": 2,
    "timed_out": false,
    "_shards": {
        "total": 1,
        "successful": 1,
        "failed": 0
    },
    "hits": {
        "total": 2,
        "max_score": 0.48288077,
        "hits": [
            {
                "_index": "yii2blog",
                "_type": "articles",
                "_id": "1",
                "_score": 0.48288077,
                "_source": {
                    "article_id": 1,
                    "post_title": "这是文章标题",
                    "post_excerpt": "这是文章描述，更新"
                },
                "highlight": {
                    "post_excerpt": [
                        "这是文章描述，更新"
                    ]
                }
            },
            {
                "_index": "yii2blog",
                "_type": "articles",
                "_id": "2",
                "_score": 0.48288077,
                "_source": {
                    "article_id": 1,
                    "post_title": "这是文章标题",
                    "post_excerpt": "这是文章描述，更新"
                },
                "highlight": {
                    "post_excerpt": [
                        "这是文章描述，更新"
                    ]
                }
            }
        ]
    }
}

中文分词设置

首先，安装中文分词插件。这里使用的是 ik，也可以考虑其他插件（比如 smartcn）。

$ ./bin/elasticsearch-plugin install https://github.com/medcl/elasticsearch-analysis-ik/releases/download/v5.5.1/elasticsearch-analysis-ik-5.5.1.zip

上面代码安装的是5.5.1版的插件，与 Elastic 5.5.1 配合使用。

接着，重新启动 Elastic，就会自动加载这个新安装的插件。

然后，新建一个 Index，指定需要分词的字段。这一步根据数据结构而异，下面的命令只针对本文。基本上，凡是需要搜索的中文字段，都要单独设置一下。

$ curl -X PUT 'localhost:9200/accounts' -d '
{
  "mappings": {
    "person": {
      "properties": {
        "user": {
          "type": "text",
          "analyzer": "ik_max_word",
          "search_analyzer": "ik_max_word"
        },
        "title": {
          "type": "text",
          "analyzer": "ik_max_word",
          "search_analyzer": "ik_max_word"
        },
        "desc": {
          "type": "text",
          "analyzer": "ik_max_word",
          "search_analyzer": "ik_max_word"
        }
      }
    }
  }
}'

上面代码中，首先新建一个名称为accounts的 Index，里面有一个名称为person的 Type。person有三个字段。

• user
• title
• desc

这三个字段都是中文，而且类型都是文本（text），所以需要指定中文分词器，不能使用默认的英文分词器。

Elastic 的分词器称为 analyzer。我们对每个字段指定分词器。

"user": {
  "type": "text",
  "analyzer": "ik_max_word",
  "search_analyzer": "ik_max_word"
}

上面代码中，analyzer是字段文本的分词器，search_analyzer是搜索词的分词器。ik_max_word分词器是插件ik提供的，可以对文本进行最大数量的分词。

分词测试

1. 自带分词器 standard

curl -v -X POST "http://localhost:9200/_analyze?analyzer=standard&pretty=true" -d "这是一段汉字"

结果

{
    "tokens": [
        {
        "token": "这",
        "start_offset": 1,
        "end_offset": 2,
        "type": "",
        "position": 0
        },
        {
        "token": "是",
        "start_offset": 2,
        "end_offset": 3,
        "type": "",
        "position": 1
        },
        {
        "token": "一",
        "start_offset": 3,
        "end_offset": 4,
        "type": "",
        "position": 2
        },
        {
        "token": "段",
        "start_offset": 4,
        "end_offset": 5,
        "type": "",
        "position": 3
        },
        {
        "token": "汉",
        "start_offset": 5,
        "end_offset": 6,
        "type": "",
        "position": 4
        },
        {
        "token": "字",
        "start_offset": 6,
        "end_offset": 7,
        "type": "",
        "position": 5
        }
    ]
}

2. 中文分词插件 ik

curl -v -X POST "http://localhost:9200/_analyze?analyzer=ik&pretty=true" -d "这是一段汉字"

结果

{
    "tokens": [
        {
        "token": "这是",
        "start_offset": 1,
        "end_offset": 3,
        "type": "CN_WORD",
        "position": 0
        },
        {
        "token": "一段",
        "start_offset": 3,
        "end_offset": 5,
        "type": "CN_WORD",
        "position": 1
        },
        {
        "token": "一",
        "start_offset": 3,
        "end_offset": 4,
        "type": "TYPE_CNUM",
        "position": 2
        },
        {
        "token": "段",
        "start_offset": 4,
        "end_offset": 5,
        "type": "COUNT",
        "position": 3
        },
        {
        "token": "汉字",
        "start_offset": 5,
        "end_offset": 7,
        "type": "CN_WORD",
        "position": 4
        },
        {
        "token": "汉",
        "start_offset": 5,
        "end_offset": 6,
        "type": "CN_WORD",
        "position": 5
        },
        {
        "token": "字",
        "start_offset": 6,
        "end_offset": 7,
        "type": "CN_CHAR",
        "position": 6
        }
    ]
}

---

参考：

• Elasticsearch Reference [2.2]Document APIs
• 全文搜索引擎 Elasticsearch 入门教程