IOC的理解,整合AOP,解耦对Service层和Dal层的依赖

来源：cnblogs　　作者：从未太晚　　时间：2018/10/8 9:08:25　　对本文有异议

DIP依赖倒置原则：系统架构时，高层模块不应该依赖于低层模块，二者通过抽象来依赖
依赖抽象，而不是细节

贯彻依赖倒置原则，左边能抽象，右边实例化的时候不能直接用抽象，所以需要借助一个第三方

高层本来是依赖低层，但是可以通过工厂(容器)来决定细节，去掉了对低层的依赖
IOC控制反转：把高层对低层的依赖，转移到第三方决定，避免高层对低层的直接依赖(是一种目的)
那么程序架构就具备良好扩展性和稳定性

DI依赖注入：是用来实现IOC的一种手段,
在构造对象时，可以自动的去初始化，对象需要的对象
构造函数注入属性注入方法注入,IOC容器初始化ApplePhone的时候通过配置文件实例化属性,方法,构造函数

using Microsoft.Practices.Unity;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Ruanmou.Interface;
using System;
using Unity.Attributes;
namespace Ruanmou.Service
{
    public class ApplePhone : IPhone
    {
        [Dependency]//属性注入：不错，但是有对容器的依赖
        public IMicrophone iMicrophone { get; set; }
        public IHeadphone iHeadphone { get; set; }
        public IPower iPower { get; set; }
        //[InjectionConstructor]
        public ApplePhone()
        {
            Console.WriteLine("{0}构造函数", this.GetType().Name);
        }
        //[InjectionConstructor]//构造函数注入：最好的，默认找参数最多的构造函数
        public ApplePhone(IHeadphone headphone)
        {
            this.iHeadphone = headphone;
            Console.WriteLine("{0}带参数构造函数", this.GetType().Name);
        }
        public void Call()
        {
            Console.WriteLine("{0}打电话", this.GetType().Name); 
        }
        [InjectionMethod]//方法注入：最不好的，增加一个没有意义的方法，破坏封装
        public void Init1234(IPower power)
        {
            this.iPower = power;
        }
    }
}

不管是构造对象，还是注入对象，这里都是靠反射做到的

有了依赖注入，才可能做到无限层级的依赖抽象，才能做到控制反转

IOC Unity容器可以通过代码注册或配置文件注册接口对应实现类,实现了不依赖具体,可以对对象全局单例,线程单例

例子1

Service业务逻辑层升级,在原有1.0的基础上添加一些功能,使用配置文件注册

      <container name="testContainer1">
        <register type="Ruanmou.Interface.IPhone,Ruanmou.Interface" mapTo="Ruanmou.Service.ApplePhone, Ruanmou.Service"/>
        <register type="Ruanmou.Interface.IPhone,Ruanmou.Interface" mapTo="Ruanmou.Service.AndroidPhone, Ruanmou.Service" name="Android"/>
        <register type="Ruanmou.Interface.IMicrophone, Ruanmou.Interface" mapTo="Ruanmou.Service.Microphone, Ruanmou.Service"/>
        <register type="Ruanmou.Interface.IHeadphone, Ruanmou.Interface" mapTo="Ruanmou.Service.Headphone, Ruanmou.Service"/>
        <register type="Ruanmou.Interface.IPower, Ruanmou.Interface" mapTo="Ruanmou.Service.Power, Ruanmou.Service"/>
        <register type="Ruanmou.IDAL.IBaseDAL, Ruanmou.IDAL" mapTo="Ruamou.DAL.BaseDAL, Ruamou.DAL"/>
      </container>
 
      <container name="testContainer">
        <register type="Ruanmou.Interface.IPhone,Ruanmou.Interface" mapTo="Ruanmou.Service.AndroidPhone, Ruanmou.Service.Extend"/>
        <register type="Ruanmou.Interface.IPhone,Ruanmou.Interface" mapTo="Ruanmou.Service.AndroidPhone, Ruanmou.Service.Extend" name="Android"/>
        <register type="Ruanmou.Interface.IMicrophone, Ruanmou.Interface" mapTo="Ruanmou.Service.Microphone, Ruanmou.Service.Extend"/>
        <register type="Ruanmou.Interface.IHeadphone, Ruanmou.Interface" mapTo="Ruanmou.Service.Headphone, Ruanmou.Service.Extend"/>
        <register type="Ruanmou.Interface.IPower, Ruanmou.Interface" mapTo="Ruanmou.Service.Power, Ruanmou.Service.Extend"/>
        <register type="Ruanmou.IDAL.IBaseDAL, Ruanmou.IDAL" mapTo="Ruamou.DAL.BaseDAL, Ruamou.DAL"/>
      </container>

只需要把服务2.0的类库(实现1.0的原有接口)dll拿过来即可使用,代码不做任何修改

例子2 业务扩展，新加功能

应该是加几个接口和实现类的映射,就可以解决了。

例子3 实现AOP

方法需要加日志，加异常管理，可以不修改原有代码，直接新加异常管理类等的类库，在Unity配置文件添加AOP配置节点即可实现

配置文件配置，

      <container name="testContainerAOP">
        <extension type="Interception"/>
        <register type="Ruanmou.Interface.IPhone,Ruanmou.Interface" mapTo="Ruanmou.Service.AndroidPhone, Ruanmou.Service.Extend">
          <interceptor type="InterfaceInterceptor"/>
          <interceptionBehavior type="Ruanmou.Framework.AOP.AuthorizeBehavior, Ruanmou.Framework"/>
          <interceptionBehavior type="Ruanmou.Framework.AOP.SmsBehavior, Ruanmou.Framework"/>
          <interceptionBehavior type="Ruanmou.Framework.AOP.ExceptionLoggingBehavior, Ruanmou.Framework"/>
          <interceptionBehavior type="Ruanmou.Framework.AOP.CachingBehavior, Ruanmou.Framework"/>
          <interceptionBehavior type="Ruanmou.Framework.AOP.LogBeforeBehavior, Ruanmou.Framework"/>
          <interceptionBehavior type="Ruanmou.Framework.AOP.ParameterCheckBehavior, Ruanmou.Framework"/>
          <interceptionBehavior type="Ruanmou.Framework.AOP.LogAfterBehavior, Ruanmou.Framework"/>
        </register>
        <register type="Ruanmou.Interface.IPhone,Ruanmou.Interface" mapTo="Ruanmou.Service.AndroidPhone, Ruanmou.Service.Extend" name="Android"/>
        <register type="Ruanmou.Interface.IMicrophone, Ruanmou.Interface" mapTo="Ruanmou.Service.Microphone, Ruanmou.Service.Extend"/>
        <register type="Ruanmou.Interface.IHeadphone, Ruanmou.Interface" mapTo="Ruanmou.Service.Headphone, Ruanmou.Service.Extend"/>
        <register type="Ruanmou.Interface.IPower, Ruanmou.Interface" mapTo="Ruanmou.Service.Power, Ruanmou.Service.Extend"/>
        <register type="Ruanmou.IDAL.IBaseDAL, Ruanmou.IDAL" mapTo="Ruamou.DAL.BaseDAL, Ruamou.DAL">
        </register>
      </container>

贴一个异常处理的AOP例子代码

namespace Ruanmou.Framework.AOP
{
    public class ExceptionLoggingBehavior : IInterceptionBehavior
    {
        public IEnumerable<Type> GetRequiredInterfaces()
        {
            return Type.EmptyTypes;
        }
        public IMethodReturn Invoke(IMethodInvocation input, GetNextInterceptionBehaviorDelegate getNext)
        {
            IMethodReturn methodReturn = getNext()(input, getNext);
            Console.WriteLine("ExceptionLoggingBehavior");
            if (methodReturn.Exception == null)
            {
                Console.WriteLine("无异常");
            }
            else
            {
                Console.WriteLine($"异常:{methodReturn.Exception.Message}");
            }
            return methodReturn;
        }
        public bool WillExecute
        {
            get { return true; }
        }
    }
}