C#使用Elasticsearch(NEST)

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C#使用Elasticsearch(NEST)

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本文介绍C#使用Elasticsearch的基本方法，并提供一个demo

以下说明中包含的http调用，为ElasticsearchTestController中编写的测试方法

初始化

引用NEST

创建ElasticClient对象

ElasticClient elasticClient = new ElasticClient(new ConnectionSettings(new Uri(address));

新增索引

关键代码

CreateIndexResponse createIndexResponse = await elasticClient.Indices.CreateAsync(indexName, createIndexDescriptor =>

{

return createIndexDescriptor.

Map(typeMappingDescriptor =>

{

return typeMappingDescriptor.Properties(propertiesSelector =>

{

foreach (PropertyInfo propertyInfo in typeof(StudentForElasticsearch).GetProperties())

{

if (!propertyInfo.CanWrite)

continue;

switch (propertyInfo.PropertyType.Name)

{

case nameof(Int16):

case nameof(Int32):

case nameof(Int64):

case nameof(UInt16):

case nameof(UInt32):

case nameof(UInt64):

case nameof(Decimal):

case nameof(Single):

case nameof(Double):

case nameof(Byte):

propertiesSelector = propertiesSelector.Number(propertyDescriptor => propertyDescriptor.Name(ToJavaScriptPropertyName(propertyInfo.Name)));

break;

case nameof(Boolean):

propertiesSelector = propertiesSelector.Boolean(propertyDescriptor => propertyDescriptor.Name(ToJavaScriptPropertyName(propertyInfo.Name)));

break;

case nameof(DateTime):

propertiesSelector = propertiesSelector.Date(propertyDescriptor => propertyDescriptor.Name(ToJavaScriptPropertyName(propertyInfo.Name)));

break;

case nameof(String):

propertiesSelector = propertiesSelector.Keyword(propertyDescriptor => propertyDescriptor.Name(ToJavaScriptPropertyName(propertyInfo.Name)));

break;

default:

break;

}

return propertiesSelector;

});

为索引添加别名

PutAliasResponse putAliasResponse = await elasticClient.Indices.PutAliasAsync(indexName, indexAliasName);

调用http://localhost:5000/api/ElasticsearchTest/CreateIndex?indexName=stu&indexAliasName=stuAliasName创建索引

查询索引结构

GET

http://xxxxxxx:9200/stu/_mapping

返回结果

{

"stu": {

"mappings": {

"properties": {

"email": {

"type": "keyword"

"id": {

"type": "float"

"name": {

"type": "keyword"

}

新增数据

关键代码

BulkResponse bulkResponse = await elasticClient.BulkAsync(bulkDescriptor =>

{

foreach (StudentForElasticsearch document in datas)

{

bulkDescriptor = bulkDescriptor.Index<StudentForElasticsearch>(bulkIndexDescriptor =>

{

return bulkIndexDescriptor.Index(indexAliasName).Id(document.Id).Document(document);

});

}

return bulkDescriptor;

});

调用http://localhost:5000/api/ElasticsearchTest/AddOrUpdateData?indexAliasName=stuAliasName新增数据

此时查询数据

GET

http://xxxxxxx:9200/stu/_search

{

"from": 0,

"size": 1000

}

返回结果

{

"took": 33,

"timed_out": false,

"_shards": {

"total": 1,

"successful": 1,

"skipped": 0,

"failed": 0

"hits": {

"total": {

"value": 2,

"relation": "eq"

"max_score": 1.0,

"hits": [

{

"_index": "stu",

"_type": "_doc",

"_id": "1",

"_score": 1.0,

"_source": {

"id": 1,

"name": "Student1",

"email": "11111@qq.com"

}

{

"_index": "stu",

"_type": "_doc",

"_id": "2",

"_score": 1.0,

"_source": {

"id": 2,

"name": "Student2",

"email": "2222@qq.com"

}

]

}

查询

关键代码

ISearchResponse<StudentForElasticsearch> searchResponse = await elasticClient.SearchAsync<StudentForElasticsearch>(searchDescriptor =>

{

return searchDescriptor.Index(indexAliasName).Query(queryContainerDescriptor =>

{

return queryContainerDescriptor.Bool(boolQueryDescriptor =>

{

if (!string.IsNullOrEmpty(name))

{

IList<Func<QueryContainerDescriptor<StudentForElasticsearch>, QueryContainer>> queryContainers = new List<Func<QueryContainerDescriptor<StudentForElasticsearch>, QueryContainer>>();

queryContainers.Add(queryContainerDescriptor =>

{

return queryContainerDescriptor.Wildcard(c => c

.Field(ToJavaScriptPropertyName(nameof(StudentForElasticsearch.Name))).Value($"{name}*"));

});

boolQueryDescriptor.Must(x => x.Bool(b => b.Should(queryContainers)));

}

return boolQueryDescriptor;

});

})

.From(0).Size(10);

});

这里采用Wildcard查询，并且只查询前10个匹配数据

调用http://localhost:5000/api/ElasticsearchTest/Get?indexAliasName=stuAliasName&name=Student2

返回结果

[{"id":2,"name":"Student2","email":"2222@qq.com"}]

删除数据

关键代码

BulkResponse bulkResponse = await elasticClient.BulkAsync(bulkDescriptor =>

{

foreach (int id in deleteIds)

{

bulkDescriptor = bulkDescriptor.Delete<StudentForElasticsearch>(bulkIndexDescriptor =>

{

return bulkIndexDescriptor.Index(indexAliasName).Id(id);

});

}

return bulkDescriptor;

});

调用http://localhost:5000/api/ElasticsearchTest/DeleteData?indexAliasName=stuAliasName

此时再查询数据，只剩下id为2的数据了

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