(精华)2020年8月18日 C#基础知识点 搜索引擎ElasticSearch的使用

(精华)2020年8月18日 C#基础知识点 搜索引擎ElasticSearch的使用

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！