 /// <summary>     /// 商品信息     /// </summary>     public class OrderInfo     {         public string Id { get; set; }          public DateTime CreateTime { get; set; }         public string Name { get; set; }         public string GoodsName { get; set; }          public string Status { get; set; }     }

1.1自动转换ES类型

    /// <summary>     /// ES操作     /// </summary>     public class ESService     {         //创建连接client         private static ElasticClient _client = new ElasticClient(new Uri("http://192.168.101.13:9200"));          //创建索引mapping         public void Mapping()         {             //创建索引，自动转换类型，order为索引名称             _client.Indices.Create("order", c => c              .Map<OrderInfo>(m => m              .AutoMap()              ));          }     }

得到order的mapping的为

 "order" : {     "mappings" : {       "properties" : {         "createTime" : {           "type" : "date"         },         "goodsName" : {           "type" : "text",           "fields" : {             "keyword" : {               "type" : "keyword",               "ignore_above" : 256             }           }         },         "id" : {           "type" : "text",           "fields" : {             "keyword" : {               "type" : "keyword",               "ignore_above" : 256             }           }         },         "name" : {           "type" : "text",           "fields" : {             "keyword" : {               "type" : "keyword",               "ignore_above" : 256             }           }         },         "status" : {           "type" : "text",           "fields" : {             "keyword" : {               "type" : "keyword",               "ignore_above" : 256             }           }         }       }     }   }

1.2通过特性指定字段的ES类型

 　　/// <summary>     /// 商品信息     /// </summary>     public class OrderInfo     {         [Keyword(Name="Id")]         public string Id { get; set; }         [Date(Name = "CreateTime")]         public DateTime CreateTime { get; set; }         [keyword]         public string Name { get; set; }         [Text]         public string GoodsName { get; set; }          public string Status { get; set; }     }

通过给字段标特性指定字段转换成的ES类型，类型有：Text，Keyword，Number，Boolean，Date等

2.插入数据

2.1.插入单条数据

 /// <summary>         /// 插入单条         /// </summary>         public void Insert()         {             var order = new OrderInfo()             {                 Id = Guid.NewGuid().ToString(),                 CreateTime = DateTime.Now,                 Name = "张三",                 GoodsName = "手机P50",                 Status = "购物车"             };             var indexResponse = _client.Index(order, i => i.Index("order"));             if(!indexResponse.IsValid)             {                 //插入失败处理             }         }

2.2批量插入数据

/// <summary>         /// 插入多条         /// </summary>         public void InsertList()         {             var orders = new List<OrderInfo>();             for(int i=1;i<=10;i++)             {                 orders.Add(new OrderInfo()                 {                     Id = Guid.NewGuid().ToString(),                     CreateTime = DateTime.Now,                     Name = "王五" + i,                     GoodsName="冰箱"+i，     　　　　　　　　　 Status="待付款"                 });             }              var bulkIndexResponse = _client.Bulk(b => b               .Index("order")               .IndexMany(orders));             if(!bulkIndexResponse.IsValid)             {                 //失败处理             }                     }

3.数据查询

3.1查询全部数据

/// <summary>         /// 查询全部         /// </summary>         public void SearchAll()         {             QueryContainer query = new QueryContainer();             query = new MatchAllQuery(); //查询全部               var searchResponse = _client.Search<OrderInfo>(s => s               .Index("order")               .Query(q=>query)               );             //获取查询数据             List<OrderInfo> datas =searchResponse.Documents.ToList();         }

3.2分页查询

 /// <summary>         /// 分页查询         /// </summary>         public void SearchPage()         {             QueryContainer query = new QueryContainer();             query = new MatchAllQuery(); //查询全部             int pageIndex = 1;             int pageSize = 5;              var searchResponse = _client.Search<OrderInfo>(s => s              .Index("order")              .Query(q => query)              .From((pageIndex-1)*pageSize) //从第几条索引开始              .Size(pageSize) //返回多少条              );             //获取查询数据             List<OrderInfo> datas = searchResponse.Documents.ToList();         }

3.3游标查询Scroll

为了避免深度分页性能问题，ES默认From&Size的查询只能查询到10000条之前的数据，要查询10000条之后的数据，需要用到游标查询

第一次查询产生scrollId，后面的查询只需要scrollId就可以记住原来的条件和查询位置，往后滚动查询

  /// <summary>         /// 游标查询         /// </summary>         public void SearchScroll()         {             MatchAllQuery query = new MatchAllQuery();//查询全部             int pageSize = 5;              var searchResponse = _client.Search<OrderInfo>(s => s              .Index("order")              .Query(q => query)              .Size(pageSize) //一次返回多少条              .Scroll("10s") //scrollId有效时间              );             //获取查询数据             List<OrderInfo> datas = searchResponse.Documents.ToList();             string scrollId = searchResponse.ScrollId;//游标Id             //后面的查询只需要用scrollId查询            var searchResponse2 = _client.Scroll<OrderInfo>("10s", scrollId);                         List<OrderInfo> datas2 = searchResponse2.Documents.ToList();          }

3.4条件查询

 /// <summary>         /// 条件查询         /// </summary>         public void SearchWhere()         {             //查询name=王五             var searchResponse = _client.Search<OrderInfo>(s => s             .Index("order")                   .Query(q => q.Term(q=>q.Name, "王五1"))           );             //获取查询数据             List<OrderInfo> datas = searchResponse.Documents.ToList();         }

Elasticsearch使用系列-.NET6对接Elasticsearch

3.5条件or查询

/// <summary>         /// 条件or查询         /// </summary>         public void SearchOr()         {            //查询 name='王五1'or name='王五二'             var searchResponse = _client.Search<OrderInfo>(s => s               .Index("order")               .Query(q => q               .Term(o=>o.Name,"王五1")||q               .Term(o=>o.Name,"王五2"))             );             //获取查询数据             List<OrderInfo> datas = searchResponse.Documents.ToList();         }

Elasticsearch使用系列-.NET6对接Elasticsearch

3.6条件And查询

 /// <summary>         /// 条件and查询         /// </summary>         public void SearchAnd()         {             //查询 name='王五1'or status='待付款'             var searchResponse = _client.Search<OrderInfo>(s => s               .Index("order")               .Query(q => q               .Term(o => o.Name, "王五1") && q               .Term("status.keyword", "待付款")) //因为status是text+keyword类型，查询字段要加上".keyword"             );             //获取查询数据             List<OrderInfo> datas = searchResponse.Documents.ToList();         }

3.7聚合统计查询

  /// <summary>         /// 聚合查询统计         /// </summary>         public void SearchAggs()         {             //求员工年龄平均值和最大年龄             var searchResponse = _client.Search<object>(s => s               .Index("employee")               .Size(0) //不返回源数据               .Aggregations(aggs=>aggs               .Average("avgage",avg=>avg.Field("age"))               .Max("maxage",max=>max.Field("age"))             ));             var datas = searchResponse.Aggregations ;                      }

Elasticsearch使用系列-.NET6对接Elasticsearch

3.8聚合分组查询

 /// <summary>         /// 聚合分组查询         /// </summary>         public void SearchAggsGroup()         {             //求员工年龄平均值和最大年龄             var searchResponse = _client.Search<object>(s => s               .Index("employee")               .Size(0) //不返回源数据               .Aggregations(aggs => aggs             .Terms("jobgroup", group => group.Field("job"))             ));             var datas = searchResponse.Aggregations;          }

Elasticsearch使用系列-.NET6对接Elasticsearch

4.sql语句查询

需要安装sql插件，参照前一篇文章，这里通过rest api向ES发起sql语句的查询

建一个参数类和HttpHelper

    public class QueryParam     {         public string query { get; set; }     }     public class HttpHelper     {         private static HttpClient _httpClient = new HttpClient();         public static string Post(QueryParam param, string url)         {             HttpContent content = new StringContent(JsonConvert.SerializeObject(param));             content.Headers.ContentType= new MediaTypeHeaderValue("application/json");             string result = _httpClient.PostAsync(url, content).Result.Content.ReadAsStringAsync().Result;             content.Dispose();             return result;         }     }

向ES发起sql语句查询

　　　　　/// <summary>         /// sql语句查询         /// </summary>         public void SearchSql()         {             QueryParam queryParam = new QueryParam();             queryParam.query = "select * from employee where job='java'";             string url = "http://192.168.101.13:9200/_xpack/sql?format=csv";             var result = HttpHelper.Post(queryParam, url);             Console.WriteLine(result);         }