前言:

最近在總結設計模式,再次看設計模式,理解又加深了不少!故來總結一下!

核心:

定義:

提供一個建立一系列相關或相互依賴物件的介面,而無需指定它們具體的類.簡要介紹一下本次的例子:建立sql和access工廠類,並建立訪問sql server的user和department;訪問access 的user和department

類圖:

核心程式碼:

IFactory介面,定義一個建立訪問User表的抽象的工廠介面

nterface IFactory
    {
        IUser CreateUser();
        IDepartment CreateDepartment();//增加介面的方法
    }

SqlServerFactory類,實現IFactory介面,例項化SqlserverUser

class SqlServerFactory :IFactory
    {
        public IUser CreateUser() { 
           return new SqlserverUser();
        }


        public IDepartment CreateDepartment()
        {
            return new SqlserverDepartment();
        }
    }

AccessFactory類,實現IFactory介面,例項化AccessUser

 class AccessFactory:IFactory
    {
        public IUser CreateUser() {
            return new AccessUser();
        }

        public IDepartment CreateDepartment()
        {
            return new AccessDepartment();
        }
    }

IUser介面,用於客戶端訪問,解除與具體資料庫訪問的耦合

interface IUser
    {
        void Insert(User user);
        User GetUser(int id);
    }

SqlserverUser類,用於訪問SQL Server的User

class SqlserverUser :IUser
    {
        public void Insert(User user) {
            Console.WriteLine("在SQL Server中給User表增加一條資訊");
        }
        public  User GetUser(int id) {
            Console.WriteLine("在SQL Server中根據Id得到User表中的一條記錄");
            return null;
        }
    }

AccessUser類,,用於訪問Access的User

class AccessUser:IUser
    {
        
            public void Insert(User user)
            {
                Console.WriteLine("在Access中給User表增加一條資訊");
            }
            public User GetUser(int id)
            {
                Console.WriteLine("在Access中根據Id得到User表中的一條記錄");
                return null;
            }
        }

User類:

class User
    {
        private int _id;

        public int Id
        {
            get { return _id; }
            set { _id = value; }
        }
        private int _name;

        public int Name
        {
            get { return _name; }
            set { _name = value; }
        }
    }

以上利用抽象工廠建立了一個使用者的介面,分別可以訪問access資料庫和sql server資料庫,這樣利用情形可以利用工廠方法可以結局,建立一個使用者的工廠,抽象的工廠的用處在哪裡呢?現在來了一個department,也要求可以訪問兩個資料庫,那麼怎麼做呢?這時利用抽象工廠再建立一個department介面:

department類:

class Department
    {
        private int _id;

        public int Id
        {
            get { return _id; }
            set { _id = value; }
        }
        private string _department;

        public string Department1
        {
            get { return _department; }
            set { _department = value; }
        }
    }

department介面:

interface IDepartment
    {
        void Insert(Department department);
        Department GetDepartment(int id);
    }

sqlServeDepartment類,用於訪問SQL Server的Department

class SqlserverDepartment : IDepartment
    {
        public void Insert(Department department) {
            Console.WriteLine("在SQL Server中給Department表增加一條記錄");        
        }
        public Department GetDepartment(int id) {
            Console.WriteLine("在SQL Server中根據ID得到deparment表中一條記錄");
            return null;
        
        }
    }

AccessDepartment類,用於訪問Access的Department

 class AccessDepartment :IDepartment
    {
        public void Insert(Department department)
        {
            Console.WriteLine("在Access中給Department表新增一條記錄");
        }

        public Department GetDepartment(int id)
        {
            Console.WriteLine("在Access中根據id得到department表一條記錄");
            return null;
        }
    }

客戶端呼叫:

 static void Main(string[] args)
        {
            User user = new User();
            Department dept = new Department();

            IFactory factory = new SqlServerFactory();

            IUser iu = factory.CreateUser();

            iu.Insert(user);
            iu.GetUser(1);

            IDepartment id = factory.CreateDepartment();
            id.Insert(dept);
            id.GetDepartment(1);
            Console.Read();

        }

執行結果:

理解抽象工廠:

我們再次看看抽象工廠的定義,提供一個建立一系列相關或相互依賴物件的介面,在這個例子,指的是使用者(User)和部門(Department)兩個介面:    IUser CreateUser();              IDepartment CreateDepartment(); 沒有指定具體的哪個使用者或者哪個部門的物件.這就是抽象工廠的精髓所在.

總結:

後續階段會持續總結設計模式,歡迎大家交流.