少有人走的路先来段起始源码：
需求是： 使用SQLServer数据库，对表User进行Insert和GetUser两个操作
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication2
{
class Program
{
static void Main(string[] args)
{
SqlserverUser sql = new SqlserverUser();
sql.Insert(new User() { ID = 1, Name = "张三" });
sql.GetUser(1);
Console.ReadKey();
}
}
public class User
{
public int ID { get; set; }
public string Name { get; set; }
}
public class SqlserverUser
{
public void Insert(User user)
{
Console.WriteLine("SQL Server给User表插入一条记录");
}
public User GetUser(int id)
{
Console.WriteLine("SQL Server根据ID得到User表一条记录");
return null;
}
}
}然后客户改了需求了。
要求即可以使用SQLServer，也可以使用Access数据库。
下面是勇哥实现的简单类工厂方式。
类图如下：
源码如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication17
{
class Program
{
static void Main(string[] args)
{
UserOperateFac fac = new UserOperateFac();
var obj= fac.GetObj(UserOperEnum.Access);
obj.Insert(new User() { ID=1, Name="张三" });
var s1= obj.GetUser(1);
Console.ReadKey();
}
}
public class User
{
public int ID { get; set; }
public string Name { get; set; }
}
public class SqlserverUser: UserOperate
{
public override void Insert(User user)
{
Console.WriteLine("SQL Server给User表插入一条记录");
}
public override User GetUser(int id)
{
Console.WriteLine("SQL Server根据ID得到User表一条记录");
return null;
}
}
public class AccessUser : UserOperate
{
public override void Insert(User user)
{
Console.WriteLine("Access给User表插入一条记录");
}
public override User GetUser(int id)
{
Console.WriteLine("Access根据ID得到User表一条记录");
return null;
}
}
public abstract class UserOperate
{
public abstract void Insert(User user);
public abstract User GetUser(int id);
}
public enum UserOperEnum
{
SQLServer,Access
}
public class UserOperateFac
{
UserOperate res = null;
public UserOperate GetObj(UserOperEnum op)
{
switch(op)
{
case UserOperEnum.SQLServer:
res = new SqlserverUser();
break;
case UserOperEnum.Access:
res = new AccessUser();
break;
}
return res;
}
}
}下面是实现的工厂模式
类图如下：
源码如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
RootFactory fac = new SqlserverUserFac();
var obj= fac.CreateOperaObj();
obj.Insert(new User() {ID=1, Name="q1" });
obj.GetUser(1);
Console.ReadKey();
}
}
public class User
{
public int ID { get; set; }
public string Name { get; set; }
}
public class SqlserverUser:UserOpera
{
public override void Insert(User user)
{
Console.WriteLine("SQL Server给User表插入一条记录");
}
public override User GetUser(int id)
{
Console.WriteLine("SQL Server根据ID得到User表一条记录");
return null;
}
}
public class AccessUser : UserOpera
{
public override void Insert(User user)
{
Console.WriteLine("Access给User表插入一条记录");
}
public override User GetUser(int id)
{
Console.WriteLine("Access根据ID得到User表一条记录");
return null;
}
}
public abstract class UserOpera
{
public abstract void Insert(User user);
public abstract User GetUser(int id);
}
public abstract class RootFactory
{
public abstract UserOpera CreateOperaObj();
}
public class SqlserverUserFac : RootFactory
{
public override UserOpera CreateOperaObj()
{
return new SqlserverUser();
}
}
public class AccessUserFac : RootFactory
{
public override UserOpera CreateOperaObj()
{
return new AccessUser();
}
}
}现在需要变化了。
原来只有一个表User需要操作，现在我们还需要操作“部门”表。
这样出现了“多种产品系列”的问题。
下面是抽象工厂模式的演示：
类图：
源码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication3
{
//抽象工厂
class Program
{
static void Main(string[] args)
{
IFactory fac = new SqlserverFactory();
var op= fac.CreateUser();
op.Insert(new User() { ID=1, Name="张三"});
op.GetUser(1);
Console.ReadKey();
}
}
public class User
{
public int ID { get; set; }
public string Name { get; set; }
}
public class 部门
{
public int ID { get; set; }
public string Name { get; set; }
}
public class SqlserverUser:UserOpera
{
public override void Insert(User user)
{
Console.WriteLine("SQL Server给User表插入一条记录");
}
public override User GetUser(int id)
{
Console.WriteLine("SQL Server根据ID得到User表一条记录");
return null;
}
}
public class AccessUser : UserOpera
{
public override void Insert(User user)
{
Console.WriteLine("Access给User表插入一条记录");
}
public override User GetUser(int id)
{
Console.WriteLine("Access根据ID得到User表一条记录");
return null;
}
}
public class Sqlserver部门 : 部门Opera
{
public override void Insert(部门 user)
{
Console.WriteLine("SQL Server给User表插入一条记录");
}
public override 部门 GetUser(int id)
{
Console.WriteLine("SQL Server根据ID得到User表一条记录");
return null;
}
}
public class Access部门 : 部门Opera
{
public override void Insert(部门 user)
{
Console.WriteLine("Access给User表插入一条记录");
}
public override 部门 GetUser(int id)
{
Console.WriteLine("Access根据ID得到User表一条记录");
return null;
}
}
public abstract class UserOpera
{
public abstract void Insert(User user);
public abstract User GetUser(int id);
}
public abstract class 部门Opera
{
public abstract void Insert(部门 user);
public abstract 部门 GetUser(int id);
}
public interface IFactory
{
UserOpera CreateUser();
部门Opera Create部门();
}
public class SqlserverFactory : IFactory
{
public UserOpera CreateUser()
{
return new SqlserverUser();
}
public 部门Opera Create部门()
{
return new Sqlserver部门();
}
}
public class AccessFactory : IFactory
{
public UserOpera CreateUser()
{
return new AccessUser();
}
public 部门Opera Create部门()
{
return new Access部门();
}
}
}描述抽象工厂的结构图：
下面是用简单工厂改造后的抽象工厂代码：
主要改进是中需要修改dbStr这个枚举，就可以快速切换数据库类型。
避免多次调用下面的代码。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication18
{
class Program
{
private const SQLEnum dbStr = SQLEnum.Access;
public enum SQLEnum
{
Access, SQLServer
}
static void Main(string[] args)
{
//RootFactory fac = new AccessUserFactory();
//var sql = fac.Create部门();
var sql = DataAccess.Create部门();
sql.Insert(new 部门() { ID = 1, Name = "张三" });
sql.GetUser(1);
Console.ReadKey();
}
public class DataAccess
{
public static UserOpera CreateUser()
{
UserOpera res = null;
switch (dbStr)
{
case SQLEnum.SQLServer:
res = new SqlserverUser();
break;
case SQLEnum.Access:
res = new AccessUser();
break;
}
return res;
}
public static 部门Opera Create部门()
{
部门Opera res = null;
switch (dbStr)
{
case SQLEnum.SQLServer:
res = new Sqlserver部门();
break;
case SQLEnum.Access:
res = new Access部门();
break;
}
return res;
}
}
public class User
{
public int ID { get; set; }
public string Name { get; set; }
}
public class 部门
{
public int ID { get; set; }
public string Name { get; set; }
}
public class SqlserverUser: UserOpera
{
public override void Insert(User user)
{
Console.WriteLine("SQL Server给User表插入一条记录");
}
public override User GetUser(int id)
{
Console.WriteLine("SQL Server根据ID得到User表一条记录");
return null;
}
}
public class AccessUser : UserOpera
{
public override void Insert(User user)
{
Console.WriteLine("Access给User表插入一条记录");
}
public override User GetUser(int id)
{
Console.WriteLine("Access根据ID得到User表一条记录");
return null;
}
}
public class Sqlserver部门 : 部门Opera
{
public override void Insert(部门 user)
{
Console.WriteLine("SQL Server给部门表插入一条记录");
}
public override 部门 GetUser(int id)
{
Console.WriteLine("SQL Server根据ID得到部门表一条记录");
return null;
}
}
public class Access部门 : 部门Opera
{
public override void Insert(部门 user)
{
Console.WriteLine("Access给部门表插入一条记录");
}
public override 部门 GetUser(int id)
{
Console.WriteLine("Access根据ID得到部门表一条记录");
return null;
}
}
public abstract class UserOpera
{
public abstract void Insert(User user);
public abstract User GetUser(int id);
}
public abstract class 部门Opera
{
public abstract void Insert(部门 user);
public abstract 部门 GetUser(int id);
}
public class AccessUserFactory: RootFactory
{
public override UserOpera CreateUser()
{
return new AccessUser();
}
public override 部门Opera Create部门()
{
return new Access部门();
}
}
public class SqlserverUserFactory: RootFactory
{
public override UserOpera CreateUser()
{
return new SqlserverUser();
}
public override 部门Opera Create部门()
{
return new Sqlserver部门();
}
}
public abstract class RootFactory
{
public abstract UserOpera CreateUser();
public abstract 部门Opera Create部门();
}
}
}---------------------
作者：hackpig
来源：www.skcircle.com
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本帖最后由 勇哥,很想停止 于 2023-11-23 14:24:04 编辑 
