Elasticsearch使用系列-.NET6对接Elasticsearch
2024-09-06 02:22:31
Elasticsearch使用系列-ES增删查改基本操作+ik分词
Elasticsearch使用系列-基本查询和聚合查询+sql插件
Elasticsearch使用系列-.NET6对接Elasticsearch
先安装nuget包
Install Package NEST
1.创建索引
先建一个Model用于映射索引
/// <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();
}
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();
}
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 ; }
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; }
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);
}
这里查询返回的格式为csv格式，数据需要自己解析成对象
更多用法参考NEST官网：https://www.elastic.co/guide/en/elasticsearch/client/net-api/current/index.html
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