大龄程序员谈架构经验内行看门道

　　前言
　　孔乙己显出极高兴的样子，将两个指头的长指甲敲着柜台，点头说：＂对呀，对呀！......回字有四样写法，你知道么？＂
　　大家好，我是44岁的大龄程序员码农阿峰。阿峰从事编程二十年了，虽然没有成为架构师，却也用过很多种架构。我觉得一招鲜走遍天，架构师常用的那几招我还是会的，听我来说道说道。我以为至少有这几招： 模板方法设计模式 反射 不重复造轮子，集众家所长 架构经验总结
　　1).模板方法设计模式的运用
　　在一个方法中定义了一个算法的骨架或者步骤，而将一些步骤延迟到子类中去实现。模板方法使得子类可以在不改变算法结构的情况下，重新定义算法中的某一些步骤。   #父类：     namespace Repository {     /// 
     /// 数据库存储泛型基类     /// 
     ///      public class BaseRepository : SimpleClient where T : class, new()     {         public ITenant itenant = null;//多租户事务         public BaseRepository(ISqlSugarClient context = null) : base(context)         {             //通过特性拿到ConfigId             var configId = typeof(T).GetCustomAttribute()?.configId;             if (configId != null)             {                 Context = DbScoped.SugarScope.GetConnectionScope(configId);//根据类传入的ConfigId自动选择             }             else             {                 Context = context ?? DbScoped.SugarScope.GetConnectionScope(0);//没有默认db0             }              itenant = DbScoped.SugarScope;//设置租户接口         }          #region add          /// 
         /// 插入实体         /// 
         ///          ///          public int Add(T t)         {             return Context.Insertable(t).IgnoreColumns(true).ExecuteCommand();         }          public int Insert(List t)         {             return Context.Insertable(t).ExecuteCommand();         }         public int Insert(T parm, Expression> iClumns = null, bool ignoreNull = true)         {             return Context.Insertable(parm).InsertColumns(iClumns).IgnoreColumns(ignoreNullColumn: ignoreNull).ExecuteCommand();         }         public IInsertable Insertable(T t)         {             return Context.Insertable(t);         }         #endregion add          #region update         public IUpdateable Updateable(T entity)         {             return Context.Updateable(entity);         }         public int Update(T entity, bool ignoreNullColumns = false)         {             return Context.Updateable(entity).IgnoreColumns(ignoreNullColumns).ExecuteCommand();         }          public int Update(T entity, Expression> expression, bool ignoreAllNull = false)         {             return Context.Updateable(entity).UpdateColumns(expression).IgnoreColumns(ignoreAllNull).ExecuteCommand();         }          /// 
         /// 根据实体类更新指定列 eg：Update(dept, it => new { it.Status }, f => depts.Contains(f.DeptId));只更新Status列，条件是包含         /// 
         ///          ///          ///          ///          public int Update(T entity, Expression> expression, Expression> where)         {             return Context.Updateable(entity).UpdateColumns(expression).Where(where).ExecuteCommand();         }          public int Update(SqlSugarClient client, T entity, Expression> expression, Expression> where)         {             return client.Updateable(entity).UpdateColumns(expression).Where(where).ExecuteCommand();         }          /// 
         ///         /// 
         ///          ///          /// 默认为true         ///          public int Update(T entity, List list = null, bool isNull = true)         {             if (list == null)             {                 list = new List()             {                 ＂Create_By＂,                 ＂Create_time＂             };             }             return Context.Updateable(entity).IgnoreColumns(isNull).IgnoreColumns(list.ToArray()).ExecuteCommand();         }                /// 
         /// 更新指定列 eg：Update(w => w.NoticeId == model.NoticeId, it => new SysNotice(){ Update_time = DateTime.Now, Title = ＂通知标题＂ });         /// 
         ///          ///          ///          public int Update(Expression> where, Expression> columns)         {             return Context.Updateable().SetColumns(columns).Where(where).RemoveDataCache().ExecuteCommand();         }         #endregion update          public DbResult UseTran(Action action)         {             try             {                 var result = Context.Ado.UseTran(() => action());                 return result;             }             catch (Exception ex)             {                 Context.Ado.RollbackTran();                 Console.WriteLine(ex.Message);                 throw;             }         }         public IStorageable Storageable(T t)         {             return Context.Storageable(t);         }         public IStorageable Storageable(List t)         {             return Context.Storageable(t);         }         /// 
         ///          /// 
         ///          /// 增删改查方法         ///          public DbResult UseTran(SqlSugarClient client, Action action)         {             try             {                 var result = client.AsTenant().UseTran(() => action());                 return result;             }             catch (Exception ex)             {                 client.AsTenant().RollbackTran();                 Console.WriteLine(ex.Message);                 throw;             }         }          public bool UseTran2(Action action)         {             var result = Context.Ado.UseTran(() => action());             return result.IsSuccess;         }          #region delete         public IDeleteable Deleteable()         {             return Context.Deleteable();         }          /// 
         /// 批量删除         /// 
         ///          ///          public int Delete(object[] obj)         {             return Context.Deleteable().In(obj).ExecuteCommand();         }         public int Delete(object id)         {             return Context.Deleteable(id).ExecuteCommand();         }         public int DeleteTable()         {             return Context.Deleteable().ExecuteCommand();         }         public bool Truncate()         {             return Context.DbMaintenance.TruncateTable();         }         #endregion delete          #region query          public bool Any(Expression> expression)         {             return Context.Queryable().Where(expression).Any();         }          public ISugarQueryable Queryable()         {             return Context.Queryable();         }          public (List, int) QueryableToPage(Expression> expression, int pageIndex = 0, int pageSize = 10)         {             int totalNumber = 0;             var list = Context.Queryable().Where(expression).ToPageList(pageIndex, pageSize, ref totalNumber);             return (list, totalNumber);         }          public (List, int) QueryableToPage(Expression> expression, string order, int pageIndex = 0, int pageSize = 10)         {             int totalNumber = 0;             var list = Context.Queryable().Where(expression).OrderBy(order).ToPageList(pageIndex, pageSize, ref totalNumber);             return (list, totalNumber);         }          public (List, int) QueryableToPage(Expression> expression, Expression> orderFiled, string orderBy, int pageIndex = 0, int pageSize = 10)         {             int totalNumber = 0;              if (orderBy.Equals(＂DESC＂, StringComparison.OrdinalIgnoreCase))             {                 var list = Context.Queryable().Where(expression).OrderBy(orderFiled, OrderByType.Desc).ToPageList(pageIndex, pageSize, ref totalNumber);                 return (list, totalNumber);             }             else             {                 var list = Context.Queryable().Where(expression).OrderBy(orderFiled, OrderByType.Asc).ToPageList(pageIndex, pageSize, ref totalNumber);                 return (list, totalNumber);             }         }          public List SqlQueryToList(string sql, object obj = null)         {             return Context.Ado.SqlQuery(sql, obj);         }          /// 
         /// 根据主值查询单条数据         /// 
         /// 主键值         /// 泛型实体         public T GetId(object pkValue)         {             return Context.Queryable().InSingle(pkValue);         }         /// 
         /// 根据条件查询分页数据         /// 
         ///          ///          ///          public PagedInfo GetPages(Expression> where, PagerInfo parm)         {             var source = Context.Queryable().Where(where);              return source.ToPage(parm);         }          public PagedInfo GetPages(Expression> where, PagerInfo parm, Expression> order, OrderByType orderEnum = OrderByType.Asc)         {             var source = Context.Queryable().Where(where).OrderByIF(orderEnum == OrderByType.Asc, order, OrderByType.Asc).OrderByIF(orderEnum == OrderByType.Desc, order, OrderByType.Desc);              return source.ToPage(parm);         }          public PagedInfo GetPages(Expression> where, PagerInfo parm, Expression> order, string orderByType)         {             return GetPages(where, parm, order, orderByType == ＂desc＂ ? OrderByType.Desc : OrderByType.Asc);         }          /// 
         /// 查询所有数据(无分页,请慎用)         /// 
         ///          public List GetAll(bool useCache = false, int cacheSecond = 3600)         {             return Context.Queryable().WithCacheIF(useCache, cacheSecond).ToList();         }          #endregion query          /// 
         /// 此方法不带output返回值         /// var list = new List();         /// list.Add(new SugarParameter(ParaName, ParaValue)); input         /// 
         ///          ///          ///          public DataTable UseStoredProcedureToDataTable(string procedureName, List parameters)         {             return Context.Ado.UseStoredProcedure().GetDataTable(procedureName, parameters);         }          /// 
         /// 带output返回值         /// var list = new List();         /// list.Add(new SugarParameter(ParaName, ParaValue, true));  output         /// list.Add(new SugarParameter(ParaName, ParaValue)); input         /// 
         ///          ///          ///          public (DataTable, List) UseStoredProcedureToTuple(string procedureName, List parameters)         {             var result = (Context.Ado.UseStoredProcedure().GetDataTable(procedureName, parameters), parameters);             return result;         }     }      /// 
     /// 分页查询扩展     /// 
     public static class QueryableExtension     {         /// 
         /// 读取列表         /// 
         ///          /// 查询表单式         /// 分页参数         ///          public static PagedInfo ToPage(this ISugarQueryable source, PagerInfo parm)         {             var page = new PagedInfo();             var total = 0;             page.PageSize = parm.PageSize;             page.PageIndex = parm.PageNum;             page.Result = source.OrderByIF(!string.IsNullOrEmpty(parm.Sort), #34;{parm.Sort} {(parm.SortType.Contains(＂desc＂) ? ＂desc＂ : ＂asc＂)}＂)                 .ToPageList(parm.PageNum, parm.PageSize, ref total);             page.TotalNum = total;             return page;         }     } }     #子类：         [AppService(ServiceLifetime = LifeTime.Transient)]     public class GenDemoRepository : BaseRepository     {         #region 业务逻辑代码         #endregion     }
　　现在大家都学精了，都使用泛型基类来简化重复的代码，标准的架构还是按经典的三层架构标准来搭建。这个是基本功，不用说太细。
　　2).反射
　　反射：是.Net Framework和.Net Core提供的一个帮助类库，可以访问dll的metadata，并且使用它。
　　反射反射，程序员的快乐  /// 
         /// 注册引用程序域中所有有AppService标记的类的服务         /// 
         ///          public static void AddAppService(this IServiceCollection services)         {             //var assemblies = AppDomain.CurrentDomain.GetAssemblies();              string []cls = new string[] { ＂Topaut.Repository＂, ＂Topaut.Service＂, ＂Topaut.Tasks＂ };             foreach (var item in cls)             {                 Assembly assembly = Assembly.Load(item);                 Register(services, assembly);             }         }          private static void Register(IServiceCollection services, Assembly assembly)         {             foreach (var type in assembly.GetTypes())             {                 var serviceAttribute = type.GetCustomAttribute();                  if (serviceAttribute != null)                 {                     var serviceType = serviceAttribute.ServiceType;                     //情况1 适用于依赖抽象编程，注意这里只获取第一个                     if (serviceType == null && serviceAttribute.InterfaceServiceType)                     {                         serviceType = type.GetInterfaces().FirstOrDefault();                     }                     //情况2 不常见特殊情况下才会指定ServiceType，写起来麻烦                     if (serviceType == null)                     {                         serviceType = type;                     }                      switch (serviceAttribute.ServiceLifetime)                     {                         case LifeTime.Singleton:                             services.AddSingleton(serviceType, type);                             break;                         case LifeTime.Scoped:                             services.AddScoped(serviceType, type);                             break;                         case LifeTime.Transient:                             services.AddTransient(serviceType, type);                             break;                         default:                             services.AddTransient(serviceType, type);                             break;                     }                     //Console.WriteLine(#34;注册：{serviceType}＂);                 }                 else                 {                     //Console.WriteLine(#34;注册：{serviceType}＂);                 }             }         }     }
　　官方各种Service注入IOC容器都是手写，框架作者利用反射实现了减少大量繁琐的固定写法，对于普通项目而言，反射的性能损耗微不足道的。
　　3).不重复造轮子集众家所长
　　有时程序员喜欢浪费生命去重复造轮子，如果是为了学习一次怎么造轮子是值得肯定的。否则就是吃饱了没事干闲的。现在是最好的时代（好多开源组件可用），也是最坏的时代（行业太卷）。框架作者使用了糖果大数据的开源组件SqlSugar来实现多数据库类型的支持，还有多租户，读写分离，分表分库这些数据库层面的数据存储方案。实现前后端分离参考了一些其他的优秀Vue实现的Admin框架。
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