在 .NET Core 中使用客户端-服务器体系结构的 WebAPI 和 Dapper

使用 .NET Core 和 Dapper 创建客户端-服务器体系结构涉及使用 .NET Core 和客户端应用程序（例如 Web、桌面或移动设备）构建服务器端 API。Dapper 是一个轻量级的对象关系映射（ORM）库，将用于与服务器应用程序中的数据库进行通信。_

在此体系结构中，系统分为两个主要实体：请求服务的客户端和提供服务的服务器。REST API 充当向各种客户端（如 Web 浏览器、移动应用程序或其他服务）提供数据的服务器。

使用 .NET Core 和 Dapper 创建客户端-服务器体系结构的步骤

服务器端：使用 Dapper 的 .NET Core Web API

1. 创建 .NET Core Web API 项目

打开终端或 Visual Studio，并创建新的 Web API 项目：

dotnet new webapi -n DapperApi  
cd DapperApi

2. 安装依赖项

添加 Dapper 和任何必要的 SQL Server 包：

dotnet add package Dapper  
dotnet add package Microsoft.Data.SqlClient

3. 配置数据库连接

在中，添加您的数据库连接字符串：appsettings.json

{  
  "ConnectionStrings": {  
  //"DefaultConnection": "Server=localhost;Database=OrderManagement;Trusted_Connection=True;MultipleActiveResultSets=true",  
  "DefaultConnection": "Server=localhost;Database=OrderManagement;User Id=sa;Password=smicr@123; Encrypt=True;TrustServerCertificate=True;"  
}

4. 创建模型

在该文件夹中，为创建一个模型类：ModelsProduct

public class Product  
{  
    public int Id { get; set; }  
    public string Name { get; set; }  
    public decimal Price { get; set; }  
}

5. 创建数据库

使用以下 SQL 脚本为 Orders 创建数据库和表。

CREATE DATABASE OrderManagement;  
  
USE OrderManagement;  
  
CREATE TABLE Products  
(  
    Id INT PRIMARY KEY IDENTITY(1,1),  
    Name NVARCHAR(100),  
    Price DECIMAL(18,2)  
);

6. 使用 Dapper 创建 Repository Layer

在您的解决方案中，创建一个文件夹，然后添加一个接口和一个类以使用 Dapper 处理数据库查询。DataAccess

接口：IProductRepository.cs

public interface IProductRepository  
{  
    Task<IEnumerable<Product>> GetAllProducts();  
    Task<Product> GetProductById(int id);  
    Task<int> AddProduct(Product product);  
    Task<int> UpdateProduct(Product product);  
    Task<int> DeleteProduct(int id);  
}

存储库：ProductRepository.cs

using Dapper;
using Microsoft.Data.SqlClient;
using Microsoft.Extensions.Configuration;

public class ProductRepository : IProductRepository
{
    private readonly DapperContext _dapperContext;

    public ProductRepository(DapperContext dapperContext)
    {
        _dapperContext = dapperContext;
    }

    public async Task<IEnumerable<Product>> GetAllProducts()
    {
        using (var connection = _dapperContext.CreateConnection())
        {
            string sql = "SELECT * FROM Products";
            return await connection.QueryAsync<Product>(sql);
        }
    }

    public async Task<Product> GetProductById(int id)
    {
        using (var connection = _dapperContext.CreateConnection())
        {
            string sql = "SELECT * FROM Products WHERE Id = @Id";
            return await connection.QueryFirstOrDefaultAsync<Product>(sql, new { Id = id });
        }
    }

    public async Task<int> AddProduct(Product product)
    {
        using (var connection = _dapperContext.CreateConnection())
        {
            string sql = "INSERT INTO Products (Name, Price) VALUES (@Name, @Price)";
            return await connection.ExecuteAsync(sql, product);
        }
    }

    public async Task<int> UpdateProduct(Product product)
    {
        using (var connection = _dapperContext.CreateConnection())
        {
            string sql = "UPDATE Products SET Name = @Name, Price = @Price WHERE Id = @Id";
            return await connection.ExecuteAsync(sql, product);
        }
    }

    public async Task<int> DeleteProduct(int id)
    {
        using (var connection = _dapperContext.CreateConnection())
        {
            string sql = "DELETE FROM Products WHERE Id = @Id";
            return await connection.ExecuteAsync(sql, new { Id = id });
        }
    }
}

7. 在依赖注入中注册仓库

在中，在 DI 容器中注册：Program.csProductRepository

using DapperApi.Contacts;  
using DapperApi.Data;  
using DapperApi.Repositorys;  
  
var builder = WebApplication.CreateBuilder(args);  
  
// Add services to the container.  
// Add services to the container  
builder.Services.AddControllers();  
  
builder.Services.AddSingleton<DapperContext>();  
// Configure Dependency Injection for services and repositories  
builder.Services.AddScoped<IProductRepository, ProductRepository>();  
  
// Configure Dapper with SQL Server  
builder.Services.AddSingleton<IConfiguration>(builder.Configuration);  
  
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle  
builder.Services.AddEndpointsApiExplorer();  
builder.Services.AddSwaggerGen();  
  
var app = builder.Build();  
  
// Configure the HTTP request pipeline.  
if (app.Environment.IsDevelopment())  
{  
    app.UseSwagger();  
    app.UseSwaggerUI();  
}  
  
app.UseHttpsRedirection();  
app.UseAuthorization();  
app.MapControllers();  
app.Run();

8. 运行应用程序

使用 POST /api/Products

{  
  "name": "Laptop",  
  "price": 3000  
}

客户端：使用控制台应用程序的示例（您可以将其扩展到 Web 或桌面应用程序）

创建控制台应用程序以与 API 交互。

创建控制台应用程序

dotnet new console -n ClientApp  
cd ClientApp

2. 安装 HttpClient

添加包以与 Web API 交互：System.Net.Http.Json

dotnet add package System.Net.Http.Json

3. 创建客户端代码以与 API 交互

在中，编写代码以调用 API：Program.cs

// See https://aka.ms/new-console-template for more information
using System.Net.Http.Json;
using System;
using System.Net.Http;
using System.Net.Http.Json;
using System.Threading.Tasks;

Console.WriteLine("Hello, World!");


        HttpClient _httpClient = new HttpClient();

        string apiUrl = "https://localhost:5001/api/products";

        // Get all products
        var products = await _httpClient.GetFromJsonAsync<Product[]>(apiUrl);
        foreach (var product in products)
        {
            Console.WriteLine($"{product.Id}: {product.Name} - ${product.Price}");
        }

        // Add a new product
        var newProduct = new Product { Name = "New Product", Price = 19.99M };
        var response = await _httpClient.PostAsJsonAsync(apiUrl, newProduct);
        if (response.IsSuccessStatusCode)
        {
            Console.WriteLine("Product added successfully.");
        }

        // Get a product by id
        var productById = await _httpClient.GetFromJsonAsync<Product>($"{apiUrl}/1");
        Console.WriteLine($"{productById.Id}: {productById.Name} - ${productById.Price}");

        // Update a product
        var updateProduct = new Product { Id = 1, Name = "Updated Product", Price = 24.99M };
        await _httpClient.PutAsJsonAsync($"{apiUrl}/1", updateProduct);

        // Delete a product
        await _httpClient.DeleteAsync($"{apiUrl}/2");

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
}

4. 运行客户端

dotnet run

结果

Hello, World!  
1: Laptop - $3000.00  
Product added successfully.  
1: Laptop - $3000.00