通过注解（特性）的方式进行对象的注册与注入，方便，灵活！
- 本篇主要讲如何去实现，下一篇主要讲如何把它集成到mvc和api环境里，实现自动的注入！
spring ioc工作的过程大致为，统一的注册组件，拦截当前请求，统一的注入当前请求所需要的组件，事实上，说到这事，.net也完全可以实现这个功能和工作方式，下来大叔来实现一下
- 定义组件注册特性
- 定义组件生命周期
- 定义组件注入特性
- 定义Ioc工厂
- 使用灵活方便
- 将注入功能集成到mvc的拦截器里
定义组件注册特性
定义在类身上
/// <summary>
/// 注册组件特性.
/// </summary>
[AttributeUsage(AttributeTargets.Class)]
public class ComponentAttribute : Attribute
{
public LifeCycle LifeCycle { get; set; } = LifeCycle.CurrentScope;
public String Named { get; set; }
}
定义组件生命周期
/// <summary>
/// 组件生命周期
/// </summary>
public enum LifeCycle
{
CurrentScope,
CurrentRequest,
Global,
}
定义组件注入特性
定义在字段上
/// <summary>
/// 注入一对象.
/// </summary>
[AttributeUsage(AttributeTargets.Field)]
public class InjectionAttribute : Attribute
{
public string Named{get;set;}
}
定义Ioc工厂
/// <summary>
/// DI工厂.
/// </summary>
public class DIFactory
{
static IContainer container;
/// <summary>
/// 手动注入.
/// </summary>
/// <returns>The resolve.</returns>
/// <typeparam name="T">The 1st type parameter.</typeparam>
public static T Resolve<T>()
{
if (container == null)
throw new ArgumentException("please run DIFactory.Init().");
return container.Resolve<T>();
}
/// <summary>
/// 手动注入.
/// </summary>
/// <returns>The by named.</returns>
/// <param name="named">Named.</param>
/// <typeparam name="T">The 1st type parameter.</typeparam>
public static T ResolveByNamed<T>(string named)
{
if (container == null)
throw new ArgumentException("please run DIFactory.Init().");
return container.ResolveNamed<T>(named);
}
/// <summary>
/// 把对象里的Inject特性的对象注入.
/// web环境下，应该使用filter拦截器将当前控制器传传InjectFromObject去注入它.
/// </summary>
/// <param name="obj">Object.</param>
public static void InjectFromObject(object obj)
{
if (obj.GetType().IsClass && obj.GetType() != typeof(string))
foreach (var field in obj.GetType().GetFields(
BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public))
{
if (field.GetCustomAttributes(false).Select(i => i.GetType())
.Contains(typeof(InjectionAttribute)))
{
InjectionAttribute inject = (InjectionAttribute)field.GetCustomAttributes(false).FirstOrDefault(i => i.GetType() == typeof(InjectionAttribute));
if (inject != null && !String.IsNullOrWhiteSpace(inject.Named))
{
field.SetValue(obj, container.ResolveNamed(inject.Named, field.FieldType));
}
else
{
field.SetValue(obj, container.Resolve(field.FieldType));
}
//递归处理它的内部字段
InjectFromObject(field.GetValue(obj));
}
}
}
/// <summary>
/// 初始化.
/// </summary>
public static void Init()
{
var builder = new ContainerBuilder();
var arr = AppDomain.CurrentDomain.GetAssemblies().Where(
x => !x.FullName.StartsWith("Dapper")
&& !x.FullName.StartsWith("System")
&& !x.FullName.StartsWith("AspNet")
&& !x.FullName.StartsWith("Microsoft"))
.SelectMany(x => x.DefinedTypes)
.Where(i => i.IsPublic && i.IsClass)
.ToList();
foreach (var type in arr)
{
try
{
if (type.GetCustomAttributes(false).Select(i => i.GetType()).Contains(typeof(ComponentAttribute)))
{
ComponentAttribute componentAttribute = (ComponentAttribute)type.GetCustomAttributes(false).FirstOrDefault(o => o.GetType() == typeof(ComponentAttribute));
if (type.GetInterfaces() != null && type.GetInterfaces().Any())
{
type.GetInterfaces().ToList().ForEach(o =>
{
registor(builder, type, o, componentAttribute);
});
}
else
{
registor(builder, type, type, componentAttribute);
}
}
}
catch (Exception)
{
throw new Exception($"Lind.DI init {type.Name} error.");
}
}
container = builder.Build();
}
/// <summary>
/// 注册组件.
/// </summary>
/// <param name="builder">Builder.</param>
/// <param name="typeImpl">Type impl.</param>
/// <param name="type">Type.</param>
/// <param name="componentAttribute">Component attribute.</param>
static void registor(ContainerBuilder builder, Type typeImpl, Type type, ComponentAttribute componentAttribute)
{
if (componentAttribute.LifeCycle == LifeCycle.Global)
{
if (componentAttribute.Named != null)
builder.RegisterType(typeImpl).Named(componentAttribute.Named, type).SingleInstance();
else
builder.RegisterType(typeImpl).As(type).SingleInstance();
}
else if (componentAttribute.LifeCycle == LifeCycle.CurrentScope)
{
if (componentAttribute.Named != null)
builder.RegisterType(typeImpl).Named(componentAttribute.Named, type).InstancePerLifetimeScope();
else
builder.RegisterType(typeImpl).As(type).InstancePerLifetimeScope();
}
else
{
if (componentAttribute.Named != null)
builder.RegisterType(typeImpl).Named(componentAttribute.Named, type).InstancePerRequest();
else
builder.RegisterType(typeImpl).As(type).InstancePerRequest();
}
}
}
使用灵活方便
支持对象与对象之间的依赖
[Component(Named="RunPeople")]
public class RunPeople : IRun
{
public void Do()
{
System.Console.WriteLine("人类跑起来!");
}
}
[Component]
public class Fly
{
[Injection(Named="RunPeople")]
Run run;
public void step1()
{
run.Do();
System.Console.WriteLine("飞行第一步!");
}
}
使用方式，程序入口先初始化DIFactory.Init();
[Injection]
Fly flyObj;
void print(){
DIFactory.Init();
DIFactory.InjectFromObject(this);
flyObj.step1();
}
static void Main(string[] args)
{
DIFactory.Init();
System.Console.WriteLine("Hello World!");
new Program().print();
}
结果
Hello World!
人类跑起来!
飞行第一步!