ElasticSearch简介
ElasticSearch 是一个开源的搜索引擎,建立在一个全文搜索引擎库 Apache Lucene™ 基础之上。 Lucene 可以说是当下最先进、高性能、全功能的搜索引擎库,无论是开源还是私有。
但是 Lucene 仅仅只是一个库。为了充分发挥其功能,你需要使用 Java 并将 Lucene 直接集成到应用程序中。 更糟糕的是,您可能需要获得信息检索学位才能了解其工作原理。Lucene 非常 复杂。
ElasticSearch 也是使用 Java 编写的,它的内部使用 Lucene 做索引与搜索,但是它的目的是使全文检索变得简单, 通过隐藏 Lucene 的复杂性,取而代之的提供一套简单一致的 RESTful API。
然而,Elasticsearch 不仅仅是 Lucene,并且也不仅仅只是一个全文搜索引擎。 它可以被下面这样准确的形容:
● 一个分布式的实时文档存储,每个字段 可以被索引与搜索
● 一个分布式实时分析搜索引擎
● 能胜任上百个服务节点的扩展,并支持 PB 级别的结构化或者非结构化数据
官方客户端在Java、.NET、PHP、Python、Ruby、Nodejs和许多其他语言中都是可用的。根据 DB-Engines 的排名显示,ElasticSearch 是最受欢迎的企业搜索引擎,其次是Apache Solr,也是基于Lucene。
ElasticSearch不支持的场景:
1、 不支持事务
2、 不支持多表关联查询业务
3、不适合频繁更新的业务场景, 读写有一定延时,写入的数据,最快1s能被检索到
默认情况下每个分片会每秒自动刷新一次,也就是说文档从Index请求到对外可见能够被搜到,最少要1秒钟,网络和CPU再快也不行。这么做是Lucene为了提高写操作的吞吐量而做出的延迟牺牲,当然这个设置是可以手动调整的,但是并不建议你去动它,会极大地影响搜索性能,刷新频率太高也会导致集群陷入瘫痪。不同的应用对实时性的定义并不一样,这取决于需求。
开始ElasticSearch之旅
1.创建 ASP.NET Core Web API 项目
创建net Core项目,将其命名为:ElasticSearchDemo,创建项目后,通过NuGet库引入Nest包
2.添加实体模型
将 ES.Models目录添加到项目根目录下
使用以下代码将 FamousPoemsModel类添加到 ES.Models 目录
using System; namespace ES.Models { /// <summary> /// /// </summary> public class FamousPoemsModel { /// <summary> /// /// </summary> public FamousPoemsModel() { } /// <summary> /// /// </summary> public string Id { get; set; } /// <summary> /// 作者 /// </summary> [Nest.Keyword] public string vcAuthor { get; set; } /// <summary> /// 内容 /// </summary> [Nest.Keyword] public string vcContent { get; set; } /// <summary> /// 标题 /// </summary> [Nest.Keyword] public string vcTitle { get; set; } /// <summary> /// 创建时间 /// </summary> public DateTime dtCreateTime { get; set; } /// <summary> /// 更新时间 /// </summary> public DateTime dtUpdateTime { get; set; } } }
3.添加配置模型
appsettings.json 添加以下ElasticSearch配置
{ "Logging": { "LogLevel": { "Default": "Information", "Microsoft": "Warning", "Microsoft.Hosting.Lifetime": "Information" } }, "AllowedHosts": "*", "ElasticSearch": { "Uri": "http://es-cn-zvp2asu64001ta726.public.elasticsearch.aliyuncs.com:9200", "UserName": "elastic", "Password": "es123456@" } }
4.创建ES.Business目录,在目录下创建ElasticSearch、IService、Service目录,废话不多说,直接上代码
using ES.Business.IService; using ES.Core; using ES.Models; using Nest; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace ES.Business.Service { /// <summary> /// /// </summary> public class FamousPoemsService : IFamousPoemsService, ITransientDependency { /// <summary> /// /// </summary> private readonly IEsUpdateService _updateService; /// <summary> /// /// </summary> private readonly IEsClientService _clientService; /// <summary> /// /// </summary> private readonly IEsIndexService _indexService; /// <summary> /// /// </summary> /// <param name="updateService"></param> /// <param name="clientService"></param> /// <param name="indexService"></param> public FamousPoemsService(IEsUpdateService updateService, IEsClientService clientService, IEsIndexService indexService) { _updateService = updateService; _clientService = clientService; _indexService = indexService; } /// <summary> /// 删除 /// </summary> /// <param name="Id"></param> /// <returns></returns> public async Task<long> DeleteAsync(string Id) { var mustFilters = new List<Func<QueryContainerDescriptor<FamousPoemsModel>, QueryContainer>>(); mustFilters.Add(t => t.Match(m => m.Field(f => f.Id).Query(Id))); var result = await _clientService.Client.DeleteByQueryAsync<FamousPoemsModel>(x => x.Index("famouspoemsmodel") .Query(q => q.Bool(b => b.Must(mustFilters)))); return result.Deleted; } /// <summary> /// 根据相关条件获取分页数据 /// </summary> /// <param name="dto"></param> /// <returns></returns> public async Task<PageModel<FamousPoemsModel>> GetPageAsync(ParameterModel dto) { PageModel<FamousPoemsModel> pageModel = new PageModel<FamousPoemsModel>(); var mustFilters = new List<Func<QueryContainerDescriptor<FamousPoemsModel>, QueryContainer>>(); if (!string.IsNullOrEmpty(dto.vcTitle)) { mustFilters.Add(t => t.Match(m => m.Field(f => f.vcTitle).Query(dto.vcTitle))); } if (dto.authors.Count() > 0) { mustFilters.Add(t => t.Terms(m => m.Field(f => f.vcAuthor).Terms(dto.authors.ToArray()))); } var total = await _clientService.Client.CountAsync<FamousPoemsModel>(x => x.Index("famouspoemsmodel") .Query(q => q.Bool(b => b.Must(mustFilters)))); if (total.Count == 0) { return pageModel; } pageModel.nDataCount = Convert.ToInt32(total.Count); pageModel.nPageCount = (int)Math.Ceiling((double)pageModel.nDataCount / dto.nPageSize); dto.nPageIndex = ((dto.nPageIndex < 1 ? 1 : dto.nPageIndex) - 1) * dto.nPageSize; var data = await _clientService.Client.SearchAsync<FamousPoemsModel>(x => x.Index("famouspoemsmodel") .Query(q => q.Bool(b => b.Must(mustFilters))).Sort(s => s.Ascending(d => d.dtCreateTime)).From(dto.nPageIndex).Size(dto.nPageSize)); pageModel.data = (List<FamousPoemsModel>)data.Documents; return pageModel; } /// <summary> /// 新增数据 /// </summary> /// <param name="poems"></param> /// <returns></returns> public async Task<bool> InsertAsync(FamousPoemsModel poems) { return await _indexService.InsertAsync(poems); } /// <summary> /// 新增批量数据 /// </summary> /// <param name="poems"></param> /// <returns></returns> public async Task<bool> InsertRangeAsync(List<FamousPoemsModel> poems) { return await _indexService.InsertRangeAsync(poems); } /// <summary> /// 通过主键局部更新数据 /// </summary> /// <param name="nId"></param> /// <param name="vcTitle"></param> /// <returns></returns> public async Task<bool> UpdateAsync(string nId, string vcTitle) { FamousPoemsModel dto = new FamousPoemsModel(); dto.vcTitle = vcTitle; dto.dtUpdateTime = DateTime.Now; var result = _updateService.Update<FamousPoemsModel>(nId, dto); return result.IsValid; } /// <summary> /// 通过条件批量局部更新某个字段数据 /// </summary> /// <returns></returns> public async Task<bool> UpdateByAuthorAsync(string vcAuthor) { var mustFilters = new List<Func<QueryContainerDescriptor<FamousPoemsModel>, QueryContainer>>(); mustFilters.Add(t => t.Match(m => m.Field(f => f.vcAuthor).Query(vcAuthor))); var result = await _clientService.Client.UpdateByQueryAsync<FamousPoemsModel>(q => q.Index("famouspoemsmodel") .Query(q => q.Bool(t => t.Must(mustFilters))) .Script(script => script.Source("ctx._source.dtUpdateTime=" + DateTime.Now + ";"))); return result.IsValid; } } }
5.将以下代码添加到 Startup.ConfigureServices
#region ES配置 services.AddEsService(options => { options.Urls = Configuration["ElasticSearch:Uri"]; options.UserName = Configuration["ElasticSearch:UserName"]; options.Password = Configuration["ElasticSearch:Password"]; }); #endregion
6.添加控制器
using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; using ES.Business.IService; using ES.Models; using ES.Util; using Microsoft.AspNetCore.Http; using Microsoft.AspNetCore.Mvc; using Newtonsoft.Json; namespace ES.Web.Controllers { /// <summary> /// 属性注入 /// </summary> public class PoemsController : ControllerBase { /// <summary> /// /// </summary> public IFamousPoemsService famousPoemsService { get; set; } /// <summary> /// 插入单条数据 /// </summary> /// <param name="poems"></param> /// <returns></returns> [HttpPost("Poems/InsertAsync")] public async Task<IActionResult> InsertAsync([FromBody]FamousPoemsModel poems) { return Content(JsonConvert.SerializeObject(await famousPoemsService.InsertAsync(poems))); } /// <summary> /// 批量插入数据 /// </summary> /// <param name="poems"></param> /// <returns></returns> [HttpPost("Poems/InsertRangeAsync")] public async Task<ActionResult> InsertRangeAsync([FromBody]List<FamousPoemsModel> poems) { return Content(JsonConvert.SerializeObject(await famousPoemsService.InsertRangeAsync(poems))); } /// <summary> /// /// </summary> /// <param name="Id"></param> /// <returns></returns> [HttpPost("Poems/DeleteAsync")] public async Task<ActionResult> DeleteAsync(string Id) { return Content(JsonConvert.SerializeObject(await famousPoemsService.DeleteAsync(Id))); } /// <summary> /// 更新 /// </summary> /// <param name="Id"></param> /// <param name="vcTitle"></param> /// <returns></returns> [HttpPost("Poems/UpdateAsync")] public async Task<ActionResult> UpdateAsync(string Id, string vcTitle) { return Content(JsonConvert.SerializeObject(await famousPoemsService.UpdateAsync(Id, vcTitle))); } /// <summary> /// 批量更新 /// </summary> /// <param name="vcAuthor"></param> /// <returns></returns> [HttpPost("Poems/UpdateByAuthorAsync")] public async Task<ActionResult> UpdateByAuthorAsync(string vcAuthor) { return Content(JsonConvert.SerializeObject(await famousPoemsService.UpdateByAuthorAsync(vcAuthor))); } /// <summary> /// 根据相关条件获取分页数据 /// </summary> /// <param name="dto"></param> /// <returns></returns> [ProducesResponseType(typeof(FamousPoemsModel), 200)] [HttpPost("Poems/GetPageAsync")] public async Task<ActionResult> GetPageAsync([FromBody]ParameterModel dto) { return Content(JsonConvert.SerializeObject(await famousPoemsService.GetPageAsync(dto))); } } }
本示例代码gitee地址:https://gitee.com/fan_zhongtuan/elasticsearchdemo.git
阿里云ElasticSearch新用户0员免费试用地址:https://www.aliyun.com/product/bigdata/elasticsearch
Elasticsearch官方权威文档:https://www.elastic.co/guide/cn/elasticsearch/guide/current/foreword_id.html