目录

一、模块配置服务

 二、配置服务的编写（配置ORM）

三、高层代码的运用（ORM实例查询 & 获取字符串）

一、模块配置服务

BookStoreHttpApiHostModule

 二、配置服务的编写（配置ORM）

(以freesql为例子)

public static class MultiDBSetup
{
    public static void AddMultiDB(this IServiceCollection services)
    {
        var configuration = services.GetConfiguration();
        var conn = configuration.GetSection("ConnectionStrings").GetChildren().FirstOrDefault().Value;//获取连接字符串
        IFreeSql fsql = new FreeSql.FreeSqlBuilder()
                            .UseConnectionString(FreeSql.DataType.SqlServer, conn)
                            .UseMonitorCommand(cmd => Console.WriteLine($"Sql：{cmd.CommandText}"))
                            .UseAutoSyncStructure(false) //取消自动同步实体结构到数据库，只有CRUD时才会生成表
                            .Build();

        services.AddSingleton<IFreeSql>(fsql);//将这个实例注册为单例服务，以便其他服务可以通过依赖注入获取 IFreeSql 的实例
    }
}

 连接字符串格式：

{
  "App": {
    "CorsOrigins": "https://*.BookStore.com"
  },
  "ConnectionStrings": {
    "Default": "Server=localhost; Database=TestABP;Trusted_Connection=True;TrustServerCertificate=true"
  },
  "Redis": {
    "Configuration": "127.0.0.1"
  }
}

关键代码：

var conn = configuration.GetSection("ConnectionStrings").GetChildren().FirstOrDefault()?.Value;//获取连接字符串

三、高层代码的运用（ORM实例查询 & 获取字符串）

namespace Acme.BookStore.Books
{
    [Route("api/freesql")]
    public class BookSearchByFreesql : ApplicationService
    {
        private readonly IFreeSql _fsql;
        private readonly IConfiguration _configuration;
        public BookSearchByFreesql(IFreeSql fsql,IConfiguration configuration)
        {
            _fsql = fsql;
            _configuration = configuration;
        }

        /// <summary>
        /// 获取书本(freesql)
        /// </summary>
        /// <returns></returns>
        [Route("freesqlgetbook")]
        [HttpGet]
        public async Task<List<AppBooks>> GetListAsync()
        {
            try
            {
                var books = await _fsql.Select<AppBooks>().ToListAsync();//通过注入的IFreeSql实例进行查询
                return books;
            }
            catch (Exception ex)
            {
                throw new Exception(ex.ToString());
            }

        }

        /// <summary>
        /// 获取连接字符串（appsetting.json）
        /// </summary>
        /// <returns></returns>
        [Route("freesqlgetconn")]
        [HttpGet]
        public async Task<string> GetConn()
        {
            return _configuration.GetSection("ConnectionStrings").GetChildren().FirstOrDefault()?.Value;//通过注入的IConfiguration获取字符串

        }
    }
}