一、聚合商品业务场景落地

1.代码实现

聚合：就是统计。做报表的核心方式

1、先在ProductController类中添加代码

/// <summary>
    /// 商品控制器
    /// </summary>
    [ApiController]
    [Route("Product")]
    public class ProductController : ControllerBase
    {
        private readonly IProductService _productService;

        public ProductController(IProductService productService)
        {
            _productService = productService;
        } 
        
        /// <summary>
        /// 聚合查询
        /// </summary>
        /// <param name="productDto"></param>
        /// <returns></returns>
        [HttpGet("AggreateTextSearch")]
        public ActionResult<ValueAggregate> GetProductsAggreateTextSearch([FromQuery] ProductDto productDto)
        {
            var products = _productService.GetProductsAggreateTextSearch(productDto);

            if (products == null)
            {
                return NotFound();
            }

            return products;
        }
    }

2、然后在ProductService类中添加代码

 /// <summary>
/// 商品服务实现
/// </summary>
public class ProductService : IProductService
{
    private readonly IMongoCollection<Product> _products;

    public ProductService()
    {
        #region 1、单实例连接
            {
                var node = new Uri("http://localhost:9200");
                // var defaultIndex = "products";

                var settings = new ConnectionSettings(node);
                //.DefaultIndex(defaultIndex);

                elasticClient = new ElasticClient(settings);
            }
            #endregion
     
    }

   public ValueAggregate GetProductsAggreateTextSearch(ProductDto productDto)
        {
            #region 1、聚合查询(平均值)
            {
                var ducmentsss = elasticClient.Search<Product>(s => s
                         .Index("products")
                         .Query(q => q.Match(mq => mq.Field(f => f.ProductTitle).Query(productDto.ProductTitle)))
                         .Aggregations(a => a.Average("ProductPrice_Average", aa => aa.Field(f => f.ProductPrice)))
                       ).Aggregations.Average("ProductPrice_Average");

                return ducmentsss;
            }
            #endregion
     }
 }

3、客户端访问，进入到浏览器进行访问

2.聚合商品数据原理

行式存储：是一行一行进行存储，

列式存储：是一列一列进存储。列式存储有利于做聚合操作。

二、查询商品分页业务场景落地

分析：当客户端通过电商微服务往Elasticsearch中添加商品数据的时候，商品数据已经被成功添加到Elasticsearch中。如何从Elasticsearch中搜索商品数据？

方案：商品分页

1、先在电商网站中创建ProductController类，在ProductController类中添加代码

/// <summary>
    /// 商品控制器
    /// </summary>
    [ApiController]
    [Route("Product")]
    public class ProductController : ControllerBase
    {
        private readonly IProductService _productService;

        public ProductController(IProductService productService)
        {
            _productService = productService;
        } 
         /// <summary>
        /// 查询商品(分页查询)
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        [HttpGet("{id}")]
        public ActionResult<IEnumerable<Product>> GetProductsByPage(int page, int pageSize)
        {
            var products = _productService.GetProductsByPage(page, pageSize).ToList();

            if (products == null)
            {
                return NotFound();
            }

            return products;
        }
    }

2、然后在电商网站中创建ProductService类，在ProductService类中添加代码

/// <summary>
/// 商品服务实现
/// </summary>
public class ProductService : IProductService
{
    private readonly IMongoCollection<Product> _products;

    public ProductService()
    {
        // 1、建立Elasticsearch连接
        var client = new MongoClient("Elasticsearch://localhost:27017");
        // 2、获取商品库(自己创建商品数据)
        var database = client.GetDatabase("ProductDB");

        // 3、获取商品表(自己创建商品数)
        _products = database.GetCollection<Product>("Product");
     
    }

  public IEnumerable<Product> GetProductsByPage(int page, int pageSize)
        {
            #region 1、直接查询
            {
                var request = new SearchRequest("products");
                request.From = (page-1)* pageSize;
                request.Size = pageSize;

                return elasticClient.Search<Product>(request).Documents;
            }
            #endregion

            #region 2、委托查询
            {
                return elasticClient.Search<Product>(s => s
                .Index("products")
                .From((page - 1) * pageSize)
                .Size(pageSize)
                ).Documents;
            }
            #endregion
        }
 }

三、删除商品业务场景落地

分析：当客户端通过电商微服务往Elasticsearch中添加商品的时候，数据量非常大，这个时候，客户端希望能够删除商品，如何删除商品？

方案：删除商品

1、先在电商网站中创建ProductController类，在ProductController类中添加代码

/// <summary>
    /// 商品控制器
    /// </summary>
    [ApiController]
    [Route("Product")]
    public class ProductController : ControllerBase
    {
        private readonly IProductService _productService;

        public ProductController(IProductService productService)
        {
            _productService = productService;
        } 
        
        /// <summary>
        /// 删除商品
        /// </summary>
        /// <param name="id"></param>
        /// <param name="product"></param>
        /// <returns></returns>
        [HttpDelete("{id}")]
        public IActionResult DeleteProduct(string id)
        {

            try
            {
                _productService.Delete(id);
            }
            catch (Exception)
            {
                throw;
            }

            return NoContent();
        }
    }

2、然后在电商网站中创建ProductService类，在ProductService类中添加代码

 /// <summary>
/// 商品服务实现
/// </summary>
public class ProductService : IProductService
{
    private readonly IMongoCollection<Product> _products;

    public ProductService()
    {
        // 1、建立Elasticsearch连接
        var client = new MongoClient("Elasticsearch://localhost:27017");
        // 2、获取商品库(自己创建商品数据)
        var database = client.GetDatabase("ProductDB");

        // 3、获取商品表(自己创建商品数)
        _products = database.GetCollection<Product>("Product");
     
    }

    public void Delete(string Id)
        {
            elasticClient.Delete<Product>(Id, idx => idx.Index("products"));
        }
 }

四、修改商品业务场景落地

分析：当客户端通过电商微服务往Elasticsearch中添加商品的时候，商品添加错误，希望能够修改商品，这个时候，客户端希望能够修改商品，如何修改商品？

方案：修改商品

1、先在电商网站中创建ProductController类，在ProductController类中添加代码

/// <summary>
    /// 商品控制器
    /// </summary>
    [ApiController]
    [Route("Product")]
    public class ProductController : ControllerBase
    {
        private readonly IProductService _productService;

        public ProductController(IProductService productService)
        {
            _productService = productService;
        } 
        
        /// <summary>
        /// 修改商品
        /// </summary>
        /// <param name="id"></param>
        /// <param name="product"></param>
        /// <returns></returns>
        [HttpPut("{id}")]
        public IActionResult PutProduct(string id, Product product)
        {
            if (id != product.Id)
            {
                return BadRequest();
            }

            try
            {
                _productService.Update(product);
            }
            catch (Exception)
            {
                throw;
            }

            return NoContent();
        }
    }

2、然后在电商网站中创建ProductService类，在ProductService类中添加代码

 /// <summary>
/// 商品服务实现
/// </summary>
public class ProductService : IProductService
{
    private readonly IMongoCollection<Product> _products;

    public ProductService()
    {
        // 1、建立Elasticsearch连接
        var client = new MongoClient("Elasticsearch://localhost:27017");
        // 2、获取商品库(自己创建商品数据)
        var database = client.GetDatabase("ProductDB");

        // 3、获取商品表(自己创建商品数)
        _products = database.GetCollection<Product>("Product");
     
    }

   		/// <summary>
        /// 更新
        /// </summary>
        /// <param name="Product"></param>
        public void Update(Product Product)
        {
            elasticClient.Update<Product>(Product.Id, idx =>
                idx.Upsert(Product).Index("products")
            );
        }
 }