Elastic Search操作入门详解编程语言

前言

Elastic Search是基于Lucene这个非常成熟的索引方案，另加上一些分布式的实现：集群，sharding，replication等。具体可以参考我同事写的文章。
本文主要介绍ES入门，包括最简单的操作和用C#代码操作ES。ES本身有很多复杂的功能，本文只是一个入门。

安装并启动ES

去https://www.elastic.co/下载zip文件，解压缩到本地硬盘。实现需要安装java环境。

双击elasticsearch.bat，启动ES。

打开浏览器，如果有类似如下输出，则启动成功。

{ 
  "name" : "Gorgeous George", 
  "cluster_name" : "elasticsearch", 
  "version" : { 
    "number" : "2.3.5", 
    "build_hash" : "90f439ff60a3c0f497f91663701e64ccd01edbb4", 
    "build_timestamp" : "2016-07-27T10:36:52Z", 
    "build_snapshot" : false, 
    "lucene_version" : "5.5.0" 
  }, 
  "tagline" : "You Know, for Search" 
} 

通过postman操作

postman是chrome的一个插件，可以作为http client模拟操作。

创建index

命令：

PUT http://localhost:9200/chzhao-index 

返回

{ 
  "acknowledged": true 
} 

存入数据

PUT http://localhost:9200/chzhao-index/employee/1 
 

body内容

{ 
    "first_name" : "John", 
    "last_name" :  "Smith", 
    "age" :        25, 
    "about" :      "I love to go rock climbing", 
    "interests": [ "sports", "music" ] 
} 

返回

{ 
  "_index": "chzhao-index", 
  "_type": "employee", 
  "_id": "1", 
  "_version": 2, 
  "_shards": { 
    "total": 2, 
    "successful": 1, 
    "failed": 0 
  }, 
  "created": false 
} 

查询数据

全部查询

查询全部数据
命令

http://localhost:9200/chzhao-index/employee/_search 

返回

{ 
  "took": 13, 
  "timed_out": false, 
  "_shards": { 
    "total": 5, 
    "successful": 5, 
    "failed": 0 
  }, 
  "hits": { 
    "total": 1, 
    "max_score": 1, 
    "hits": [ 
      { 
        "_index": "chzhao-index", 
        "_type": "employee", 
        "_id": "1", 
        "_score": 1, 
        "_source": { 
          "first_name": "chunhui", 
          "last_name": "zhao", 
          "age": 31, 
          "about": "i love keke", 
          "interests": [ 
            "go", 
            "coding" 
          ] 
        } 
      } 
    ] 
  } 
} 

根据某一个字段查询

输入

http://localhost:9200/chzhao-index/employee/_search?q=last_name:Zhao 

返回

{ 
  "took": 10, 
  "timed_out": false, 
  "_shards": { 
    "total": 5, 
    "successful": 5, 
    "failed": 0 
  }, 
  "hits": { 
    "total": 1, 
    "max_score": 0.30685282, 
    "hits": [ 
      { 
        "_index": "chzhao-index", 
        "_type": "employee", 
        "_id": "1", 
        "_score": 0.30685282, 
        "_source": { 
          "first_name": "chunhui", 
          "last_name": "zhao", 
          "age": 31, 
          "about": "i love keke", 
          "interests": [ 
            "go", 
            "coding" 
          ] 
        } 
      } 
    ] 
  } 
} 

使用DSL语句查询

输入

POST http://localhost:9200/chzhao-index/employee/_search 

参数
参数要放在body里面。因为这样，不能用put方法。

{ 
    "query" : { 
        "match" : { 
            "last_name" : "Zhao" 
        } 
    } 
} 

返回

{ 
  "took": 12, 
  "timed_out": false, 
  "_shards": { 
    "total": 5, 
    "successful": 5, 
    "failed": 0 
  }, 
  "hits": { 
    "total": 1, 
    "max_score": 0.30685282, 
    "hits": [ 
      { 
        "_index": "chzhao-index", 
        "_type": "employee", 
        "_id": "1", 
        "_score": 0.30685282, 
        "_source": { 
          "first_name": "chunhui", 
          "last_name": "zhao", 
          "age": 31, 
          "about": "i love keke", 
          "interests": [ 
            "go", 
            "coding" 
          ] 
        } 
      } 
    ] 
  } 
} 

c#代码

c#代码应用了NEST等包，具体如下。

<?xml version="1.0" encoding="utf-8"?> 
<packages> 
  <package id="Elastic" version="1.0.3.0" targetFramework="net45" /> 
  <package id="Elasticsearch.Net" version="2.4.3" targetFramework="net45" /> 
  <package id="NEST" version="2.4.3" targetFramework="net45" /> 
  <package id="Newtonsoft.Json" version="9.0.1" targetFramework="net45" /> 
</packages> 

核心代码

namespace ElasticSearchDemo 
{ 
     
    public class Person 
    { 
        public string Id { get; set; } 
        public string Firstname { get; set; } 
        public string Lastname { get; set; } 
        public string[] Chains { get; set; } 
        public string Content { get; set; } 
    } 
} 
 

using Nest; 
using Newtonsoft.Json; 
using System; 
using System.Collections.Generic; 
 
namespace ElasticSearchDemo 
{ 
    class ESTool 
    { 
        private ElasticClient esClient = null; 
        private string index = "test-index"; 
        public ESTool() 
        { 
            var node = new Uri("http://localhost:9200"); 
            ConnectionSettings settings = new ConnectionSettings(node); 
            settings.DefaultIndex(index); 
            this.esClient = new ElasticClient(settings); 
        } 
        public void Save() 
        { 
            IEnumerable<Person> persons = new List<Person> 
            { 
                new Person() 
                { 
                    Id = "4", 
                    Firstname = "chunhui", 
                    Lastname = "zhao", 
                    Chains = new string[]{ "a","b","c" }, 
                    Content = "dad" 
                }, 
                new Person() 
                { 
                    Id = "5", 
                    Firstname = "keke", 
                    Lastname = "zhao", 
                    Chains = new string[]{ "x","y","z" }, 
                    Content = "daughter" 
                } 
            }; 
            this.esClient.IndexMany<Person>(persons, index); 
        } 
 
        public void Search() 
        { 
            var rs = this.esClient.Search<Person>(s => s.Index(index)); 
            Console.WriteLine(JsonConvert.SerializeObject(rs.Documents)); 
 
        } 
    } 
} 
 

参考

Elasticsearch 权威指南（中文版）