C#基础知识点搜索引擎ElasticSearch的使用

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C#基础知识点搜索引擎ElasticSearch的使用

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项目需要添加Elasticsearch.Net和Nest

相关文档地址

Elasticsearch文档：https://www.elastic.co/guide/en/elasticsearch/reference/current/index.html

Elasticsearch.Net和Nest官方文档：https://www.elastic.co/guide/en/elasticsearch/client/net-api/7.x/index.html

1、封装ElasticClient提供者

1）创建ElasticSearch配置类

public class EsConfig : IOptions<EsConfig>

{

public List<string> Urls { get; set; }

public EsConfig Value => this;

}

2）创建ElasticSearch提供者接口以及类

/// <summary>

/// ElasticClient 提供者接口

/// </summary>

public interface IEsClientProvider

{

/// <summary>

/// 获取ElasticClient

/// </summary>

/// <returns></returns>

ElasticClient GetClient();

/// <summary>

/// 指定index获取ElasticClient

/// </summary>

/// <param name="indexName"></param>

/// <returns></returns>

ElasticClient GetClient(string indexName);

}

/// <summary>

/// ElasticClient提供者

/// </summary>

public class EsClientProvider : IEsClientProvider

{

private readonly IOptions<EsConfig> _EsConfig;

public EsClientProvider(IOptions<EsConfig> esConfig)

{

_EsConfig = esConfig;

}

/// <summary>

/// 获取elastic client

/// </summary>

/// <returns></returns>

public ElasticClient GetClient()

{

if (_EsConfig == null || _EsConfig.Value == null || _EsConfig.Value.Urls == null || _EsConfig.Value.Urls.Count < 1)

{

throw new Exception("urls can not be null");

}

return GetClient(_EsConfig.Value.Urls.ToArray(), "");

}

/// <summary>

/// 指定index获取ElasticClient

/// </summary>

/// <param name="indexName"></param>

/// <returns></returns>

public ElasticClient GetClient(string indexName)

{

if (_EsConfig == null || _EsConfig.Value == null || _EsConfig.Value.Urls == null || _EsConfig.Value.Urls.Count < 1)

{

throw new Exception("urls can not be null");

}

return GetClient(_EsConfig.Value.Urls.ToArray(), indexName);

}

/// <summary>

/// 根据url获取ElasticClient

/// </summary>

/// <param name="url"></param>

/// <param name="defaultIndex"></param>

/// <returns></returns>

private ElasticClient GetClient(string url, string defaultIndex = "")

{

if (string.IsNullOrWhiteSpace(url))

{

throw new Exception("es 地址不可为空");

}

var uri = new Uri(url);

var connectionSetting = new ConnectionSettings(uri);

if (!string.IsNullOrWhiteSpace(url))

{

connectionSetting.DefaultIndex(defaultIndex);

}

return new ElasticClient(connectionSetting);

}

/// <summary>

/// 根据urls获取ElasticClient

/// </summary>

/// <param name="urls"></param>

/// <param name="defaultIndex"></param>

/// <returns></returns>

private ElasticClient GetClient(string[] urls, string defaultIndex = "")

{

if (urls == null || urls.Length < 1)

{

throw new Exception("urls can not be null");

}

var uris = urls.Select(p => new Uri(p)).ToArray();

var connectionPool = new SniffingConnectionPool(uris);

var connectionSetting = new ConnectionSettings(connectionPool);

if (!string.IsNullOrWhiteSpace(defaultIndex))

{

connectionSetting.DefaultIndex(defaultIndex);

}

return new ElasticClient(connectionSetting);

}

---------用户密码验证（注释部分），可以配置在EsConfig中---------

/// <summary>

/// 根据urls获取ElasticClient

/// </summary>

/// <param name="urls"></param>

/// <param name="defaultIndex"></param>

/// <returns></returns>

public ElasticClient GetClient(string[] urls, string defaultIndex = "")

{

if (urls == null || urls.Length < 1)

{

throw new Exception("urls can not be null");

}

var uris = urls.Select(p => new Uri(p)).ToArray();

var connectionPool = new SniffingConnectionPool(uris);

var connectionSetting = new ConnectionSettings(connectionPool);

if (!string.IsNullOrWhiteSpace(defaultIndex))

{

connectionSetting.DefaultIndex(defaultIndex);

}

//connectionSetting.BasicAuthentication("", ""); //设置账号密码

return new ElasticClient(connectionSetting);

}

2、封装操作ElasticSearch实现

1)、扩展ElasticClient类

/// <summary>

/// ElasticClient 扩展类

/// </summary>

public static class ElasticClientExtension

{

/// <summary>

/// 创建索引

/// </summary>

/// <typeparam name="T"></typeparam>

/// <param name="elasticClient"></param>

/// <param name="indexName"></param>

/// <param name="numberOfShards"></param>

/// <param name="numberOfReplicas"></param>

/// <returns></returns>

public static bool CreateIndex<T>(this ElasticClient elasticClient, string indexName = "", int numberOfShards = 5, int numberOfReplicas = 1) where T : class

{

if (string.IsNullOrWhiteSpace(indexName))

{

indexName = typeof(T).Name;

}

if (elasticClient.Indices.Exists(indexName).Exists)

{

return false;

}

else

{

var indexState = new IndexState()

{

Settings = new IndexSettings()

{

NumberOfReplicas = numberOfReplicas,

NumberOfShards = numberOfShards,

};

var response = elasticClient.Indices.Create(indexName, p => p.InitializeUsing(indexState).Map<T>(p => p.AutoMap()));

return response.Acknowledged;

}

2)、创建ElasticSearch操作基类

/// <summary>

/// 接口限定

/// </summary>

public interface IBaseEsContext { }

/// <summary>

/// es操作基类

/// </summary>

/// <typeparam name="T"></typeparam>

public abstract class BaseEsContext<T> : IBaseEsContext where T : class

{

protected IEsClientProvider _EsClientProvider;

public abstract string IndexName { get; }

public BaseEsContext(IEsClientProvider provider)

{

_EsClientProvider = provider;

}

/// <summary>

/// 批量更新

/// </summary>

/// <param name="tList"></param>

/// <returns></returns>

public bool InsertMany(List<T> tList)

{

var client = _EsClientProvider.GetClient(IndexName);

if (!client.Indices.Exists(IndexName).Exists)

{

client.CreateIndex<T>(IndexName);

}

var response = client.IndexMany(tList);

//var response = client.Bulk(p=>p.Index(IndexName).IndexMany(tList));

return response.IsValid;

}

/// <summary>

/// 获取总数

/// </summary>

/// <returns></returns>

public long GetTotalCount()

{

var client = _EsClientProvider.GetClient(IndexName);

var search = new SearchDescriptor<T>().MatchAll(); //指定查询字段 .Source(p => p.Includes(x => x.Field("Id")));

var response = client.Search<T>(search);

return response.Total;

}

/// <summary>

/// 根据Id删除数据

/// </summary>

/// <returns></returns>

public bool DeleteById(string id)

{

var client = _EsClientProvider.GetClient(IndexName);

var response = client.Delete<T>(id);

return response.IsValid;

}

3)、具体操作类（示例）

/// <summary>

/// 地址操作类

/// </summary>

public class AddressContext : BaseEsContext<Address>

{

/// <summary>

/// 索引名称

/// </summary>

public override string IndexName => "address";

public AddressContext(IEsClientProvider provider) : base(provider)

{

}

/// <summary>

/// 获取地址

/// </summary>

/// <param name="province"></param>

/// <param name="pageIndex"></param>

/// <param name="pageSize"></param>

/// <returns></returns>

public List<Address> GetAddresses(string province, int pageIndex, int pageSize)

{

var client = _EsClientProvider.GetClient(IndexName);

var musts = new List<Func<QueryContainerDescriptor<Address>, QueryContainer>>();

musts.Add(p => p.Term(m => m.Field(x=>x.Pronvince).Value(province)));

var search = new SearchDescriptor<Address>();

// search = search.Index(IndexName).Query(p => p.Bool(m => m.Must(musts))).From((pageIndex - 1) * pageSize).Take(pageSize);

search =search.Query(p => p.Bool(m => m.Must(musts))).From((pageIndex - 1) * pageSize).Take(pageSize);

var response = client.Search<Address>(search);

return response.Documents.ToList();

}

/// <summary>

/// 获取所有地址

/// </summary>

/// <returns></returns>

public List<Address> GetAllAddresses()

{

var client = _EsClientProvider.GetClient(IndexName);

var searchDescriptor = new SearchDescriptor<Address>();

// searchDescriptor = searchDescriptor.Index(IndexName).Query(p => p.MatchAll());

searchDescriptor = searchDescriptor.Query(p => p.MatchAll());

var response = client.Search<Address>(searchDescriptor);

return response.Documents.ToList();

}

/// <summary>

/// 删除指定城市的数据

/// </summary>

/// <param name="city"></param>

/// <returns></returns>

public bool DeleteByQuery(string city)

{

var client = _EsClientProvider.GetClient(IndexName);

var musts = new List<Func<QueryContainerDescriptor<Address>, QueryContainer>>();

musts.Add(p=>p.Term(m=>m.Field(f=>f.City).Value(city)));

var search = new DeleteByQueryDescriptor<Address>().Index(IndexName);

search = search.Query(p => p.Bool(m => m.Must(musts)));

var response = client.DeleteByQuery<Address>(p=>search);

return response.IsValid;

}

address类

[ElasticsearchType(IdProperty = "Id")]

public class Address

{

[Keyword]

public string Id { get; set; }

[Keyword]

public string Country { get; set; }

[Keyword]

public string City { get; set; }

[Keyword]

public string Pronvince { get; set; }

[Keyword]

public string Area { get; set; }

[Text]

public string Address1 { get; set; }

}

3、项目中注入和使用ElasticSearch

1)、配置文件

1 "EsConfig": {

2 "ConnectionStrings": [ "http://127.0.0.1:9200/" ]

3 }

2)、注入ElasticSearch

services.Configure<EsConfig>(options =>

{

options.Urls = Configuration.GetSection("EsConfig:ConnectionStrings").GetChildren().ToList().Select(p => p.Value).ToList();

});

services.AddSingleton<IEsClientProvider, EsClientProvider>();

var types = Assembly.Load("John.DotNetCoreStudy.EsCommon").GetTypes().Where(p => !p.IsAbstract && (p.GetInterfaces().Any(i => i == typeof(IBaseEsContext)))).ToList();

types.ForEach(p =>

services.AddTransient(p)

);

3)、Controller类中使用

[Route("api/[controller]")]

[ApiController]

public class AddressController : ControllerBase

{

private AddressContext _AddressContext;

public AddressController(AddressContext context)

{

_AddressContext = context;

}

/// <summary>

/// 新增或者修改

/// </summary>

/// <param name="address"></param>

[HttpPost("添加地址")]

public void AddAddress(List<Address> addressList)

{

if (addressList == null || addressList.Count < 1)

{

return;

}

_AddressContext.InsertMany(addressList);

}

/// <summary>

/// 删除地址

/// </summary>

/// <param name="id"></param>

[HttpPost("deleteAddress")]

public void DeleteAdress(string id)

{

_AddressContext.DeleteById(id);

}

/// <summary>

/// 获取所有与地址

/// </summary>

/// <returns></returns>

[HttpGet("getAllAddress")]

public List<Address> GetAllAddress()

{

return _AddressContext.GetAllAddresses();

}

/// <summary>

/// 获取地址总数

/// </summary>

/// <returns></returns>

[HttpGet("getAddressTotalCount")]

public long GetAddressTotalCount()

{

return _AddressContext.GetTotalCount();

}

/// <summary>

/// 分页获取（可以进一步封装查询条件）

/// </summary>

/// <param name="province"></param>

/// <param name="pageIndex"></param>

/// <param name="pageSize"></param>

/// <returns></returns>

[HttpPost("getAddressByProvince")]

public List<Address> GetAddressByProvince(string province,int pageIndex,int pageSize)

{

return _AddressContext.GetAddresses(province,pageIndex,pageSize);

}

4、测试（略）

当然es还有很多操作的，聚合查询、不同条件的查询（范围查询、匹配查询等等）、分词等。具体可以去查看其官方文档对应实现！

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