使用Microsoft.Practices.Unity 依賴注入

時間 2019-11-18

標籤使用 microsoft.practices.unity microsoft practices unity 依賴注入欄目 Windows 简体版

原文原文鏈接

Unity是微軟Patterns & Practices團隊所開發的一個輕量級的，而且可擴展的依賴注入(Dependency Injection)容器，它支持經常使用的三種依賴注入方式：構造器注入(Constructor Injection)、屬性注入(Property Injection)，以及方法調用注入(Method Call Injection).mysql

假設咱們有下面的場景代碼，在代碼裏面有一個很簡單的customer對象，customer 對象有個save 方法，這個方法經過調用ICustomerDataAccess.Save將數據持久到數據庫中, 在列子中咱們實現了dataaccess的sql版本和mysql版本，也就是說咱們這個customer對象，能夠支持持久化到sql server 或 mysql.sql

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Practices.Unity;

namespace UnitySample
{
    public interface ICustomerDataAccess
    {
        void Save(Customer c);
    }

    public class CustomerSqlDataAccess : ICustomerDataAccess
    {
        public void Save(Customer c)
        {
            Console.Write("{2}, save data id:{0},name{1}",c.Id,c.Name,this.GetType().ToString());
        }
    }

    public class CustomerMysqlDataAccess : ICustomerDataAccess
    {
        public void Save(Customer c)
        {
            Console.Write("{2}, save data id:{0},name{1}", c.Id, c.Name, this.GetType().ToString());
        }
    }

    public class Customer
    {
        public ICustomerDataAccess CustomerDataAccess { get; set; }

        public string Id { get; set; }
        public string Name { get; set; }

        public void Save()
        {
            CustomerDataAccess.Save(this);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {

        }
    }
}

傳統作法多是在配置文件中填幾個一個變量 dbType = sql or my sql. 而後在customer 對象中根據設定的db type 來實力化不一樣的dataaccess.數據庫

代碼可能會是下面這個樣子，這樣的話，customer 對象實際上依賴於CustomerSqlDataAccess 和 CustomerSqlDataAccess 的，並且，將來好比要新增長其餘數據庫的支持，則必須修改customer 對象的源代碼。函數

 public Customer()
 {
            if (DbType = "sql") { CustomerDataAccess = new CustomerSqlDataAccess(); } else { CustomerDataAccess = new CustomerSqlDataAccess(); } }

下面咱們使用unity 來解除customer 對象對 CustomerSqlDataAccess 和 CustomerSqlDataAccess 的依賴。this

1、屬性注入(Property Injection)

1. 配置unityspa

　　爲了之後調用方便，我這裏創建了一個靜態方法，而後注入了兩個dataaccess。code

 public class UnitySetup
    {
        public static void Config()
        {
            var container = new UnityContainer();
            container.RegisterType<ICustomerDataAccess, CustomerSqlDataAccess>();
            container.RegisterType<ICustomerDataAccess, CustomerSqlDataAccess>("mysql");
        }
    }

　　而後咱們須要在Main函數中調用這個方法配置unity containter.server

　　　　　static void Main(string[] args)
        {
            UnitySetup.Config();
        }

2. 標記屬性注入對象

　　這步很簡單，直接在customer 類中的ICustomerDataAccess 定義上面添加[Dependency]標註便可。blog

[Dependency]
public ICustomerDataAccess CustomerDataAccess { get; set; }

3. 經過resove 獲取對象

            var container = new UnityContainer();
            UnitySetup.Config(container);
            var sqlCustomer = container.Resolve<ICustomerDataAccess>();
            var mysqlCustomer = container.Resolve<ICustomerDataAccess>("mysql");

上面的代碼就分別獲取了CustomerSqlDataAccess 實例和CustomerSqlDataAccess實例

二、構造器注入(Constructor Injection)

1. 配置unity

  unityContainer.RegisterType<Customer>(
                new InjectionConstructor(new ResolvedParameter<ICustomerDataAccess>()));
            unityContainer.RegisterType<Customer>("mysqlCustomer",
                new InjectionConstructor(new ResolvedParameter<ICustomerDataAccess>("mysql")));

添加兩行註冊customer 對想到container.

2. 獲取

 var sqlCustomer = container.Resolve<Customer>(); var myqlCustomer = container.Resolve<Customer>("mysqlCustomer");

完整代碼以下

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Practices.Unity;

namespace UnitySample
{
    
    public interface ICustomerDataAccess
    {
        void Save(Customer c);
    }

    public class CustomerSqlDataAccess : ICustomerDataAccess
    {
        public void Save(Customer c)
        {
            Console.WriteLine("{2}, save data id:{0},name{1}",c.Id,c.Name,this.GetType().ToString());
        }
    }

    public class CustomerMysqlDataAccess : ICustomerDataAccess
    {
        public void Save(Customer c)
        {
            Console.WriteLine("{2}, save data id:{0},name{1}", c.Id, c.Name, this.GetType().ToString());
        }
    }

    public class UnitySetup
    {
        public static void Config(IUnityContainer unityContainer)
        {
            unityContainer.RegisterType<ICustomerDataAccess, CustomerSqlDataAccess>();
            unityContainer.RegisterType<ICustomerDataAccess, CustomerMysqlDataAccess>("mysql");
            unityContainer.RegisterType<Customer>(
                new InjectionConstructor(new ResolvedParameter<ICustomerDataAccess>()));
            unityContainer.RegisterType<Customer>("mysqlCustomer",
                new InjectionConstructor(new ResolvedParameter<ICustomerDataAccess>("mysql")));
        }
    }

    public class Customer
    {
        private ICustomerDataAccess CustomerDataAccess { get; set;}

        public string Id { get; set; }
        public string Name { get; set; }

        public Customer(ICustomerDataAccess customerDataAccess)
        {
            CustomerDataAccess = customerDataAccess;
        }
        public void Save()
        {
            CustomerDataAccess.Save(this);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            var container = new UnityContainer();
            UnitySetup.Config(container);
            var sqlCustomer = container.Resolve<Customer>();
            var myqlCustomer = container.Resolve<Customer>("mysqlCustomer");

            sqlCustomer.Save();
            myqlCustomer.Save();
            
            Console.ReadKey();
        }
    }
}

三、方法調用注入(Method Call Injection)

方法調用注入和輸入注入有點相似，只須要在調用的方法上面添加[InjectionMethod] 標註便可

1. 配置unity

 unityContainer.RegisterType<Customer>("mysqlCustomer", new InjectionMethod("SetDataAccess", new ResolvedParameter<ICustomerDataAccess>("mysql")));

2. 獲取

 var sqlCustomer = container.Resolve<Customer>();
 var myqlCustomer = container.Resolve<Customer>("mysqlCustomer");

完成後的代碼以下

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Practices.Unity;

namespace UnitySample
{
    
    public interface ICustomerDataAccess
    {
        void Save(Customer c);
    }

    public class CustomerSqlDataAccess : ICustomerDataAccess
    {
        public void Save(Customer c)
        {
            Console.WriteLine("{2}, save data id:{0},name{1}",c.Id,c.Name,this.GetType().ToString());
        }
    }

    public class CustomerMysqlDataAccess : ICustomerDataAccess
    {
        public void Save(Customer c)
        {
            Console.WriteLine("{2}, save data id:{0},name{1}", c.Id, c.Name, this.GetType().ToString());
        }
    }

    public class UnitySetup
    {
        public static void Config(IUnityContainer unityContainer)
        {
            unityContainer.RegisterType<ICustomerDataAccess, CustomerSqlDataAccess>();
            unityContainer.RegisterType<ICustomerDataAccess, CustomerMysqlDataAccess>("mysql");
            
            unityContainer.RegisterType<Customer>("mysqlCustomer",
                new InjectionMethod("SetDataAccess", new ResolvedParameter<ICustomerDataAccess>("mysql")));
        }
    }

    public class Customer
    {
        private ICustomerDataAccess CustomerDataAccess { get; set;}
        public string Id { get; set; }
        public string Name { get; set; }
      
        public void Save()
        {
            CustomerDataAccess.Save(this);
        }

        [InjectionMethod]
        public void SetDataAccess(ICustomerDataAccess dataAccess)
        {
            CustomerDataAccess = dataAccess;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            var container = new UnityContainer();
            UnitySetup.Config(container);
            var sqlCustomer = container.Resolve<Customer>();
            var mysqlCustomer = container.Resolve<Customer>("mysqlCustomer");
            sqlCustomer.Save();
            mysqlCustomer.Save();
            Console.ReadKey();
        }
    }
}