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本篇文章给大家分享的是有关NetCore中怎么利用Transitional自定义注解事物，小编觉得挺实用的，因此分享给大家学习，希望大家阅读完这篇文章后可以有所收获，话不多说，跟着小编一起来看看吧。
之前实现了NetCore实现自定义IOC容器注入，在Controller使用事物的过程中思考是否能够像Spring一样通过自定义注解实现事物管理，思路图如下
事物的动作拆分只需要根据当前执行线程划分Connection对象并开启事物即可，重点是在Emit代码织入过程中对异常捕捉的处理
处理过程中主要会用到BeginExceptionBlock开启try代码块，BeginCatchBlock开启catch代码块，EndExceptionBlock结束异常捕捉代码块
创建事物注解Transitional用来标记Controller中需要事物执行的方法
[AttributeUsage(AttributeTargets.Method)]
public class Transitional : System.Attribute
{
public bool AutoRollBack { set; get; }
public Transitional()
{
AutoRollBack = true;
}
}Emit编织时需要注意异常捕捉时有返回值时建立全局变量返回，执行事物管理器类的静态方法直接使用call，例如 ilOfMethod.Emit(OpCodes.Call, typeof(TransitionManage).GetMethod("DoRollBack"))，同时Controller被拦截的方法需要标记Transitional注解且同时是虚方法
被代理类示例
public class TransitionalMovie{
[Transitional]public virtual void Test1(){
Console.WriteLine("Test1");
}
[Transitional]public virtual string Test2(){
Console.WriteLine("Test2");throw new Exception("111");return "Hello";
}
[Transitional(AutoRollBack = false)]public virtual void Test3(string Key){
Console.WriteLine("Test3");
Console.WriteLine(Key);
}IOC使用示例，IOC容器原理可参考c#通过Emit方式实现动态代理
var container = new ContainerBuilder();
container.RegisterType<TransitionalMovie>().EnableIntercept();
container.Build();
TransitionalMovie tm = container.Resolve<TransitionalMovie>();
tm.Test1(); string result = tm.Test2();
Console.WriteLine(result);
tm.Test3("世界第一等");动态代理生成类反编译代码
动态代理包含异常拦截与事物的全部代码
public static Object CreateProxyObject(Type InterfaceType, Type ImpType, Type InterceptType, bool inheritMode = true, bool isInterceptAllMethod = true){string nameOfAssembly = ImpType.Name + "ProxyAssembly";string nameOfModule = ImpType.Name + "ProxyModule";string nameOfType = ImpType.Name + "Proxy";var assemblyName = new AssemblyName(nameOfAssembly);
ModuleBuilder moduleBuilder = null;var assembly = AssemblyBuilder.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
moduleBuilder = assembly.DefineDynamicModule(nameOfModule);
TypeBuilder typeBuilder;if (inheritMode)
{
typeBuilder = moduleBuilder.DefineType(
nameOfType, TypeAttributes.Public, ImpType);
}else{
typeBuilder = moduleBuilder.DefineType(
nameOfType, TypeAttributes.Public, null, new[] { InterfaceType });
}
InjectInterceptor(typeBuilder, ImpType, InterceptType, inheritMode, isInterceptAllMethod);var t = typeBuilder.CreateType();return Activator.CreateInstance(t);
}private static void InjectInterceptor(TypeBuilder typeBuilder, Type ImpType, Type InterceptType, bool inheritMode, bool isInterceptAllMethod){#region 变量定义// ---- 变量定义 ----var constructorBuilder = typeBuilder.DefineConstructor(
MethodAttributes.Public, CallingConventions.Standard, null);var ilOfCtor = constructorBuilder.GetILGenerator();//---- 拦截类对象定义 ----if (InterceptType == null)
{
InterceptType = typeof(DefaultIntercept);
}//声明var fieldInterceptor = typeBuilder.DefineField( "_interceptor", InterceptType, FieldAttributes.Private);//赋值ilOfCtor.Emit(OpCodes.Ldarg_0);
ilOfCtor.Emit(OpCodes.Newobj, InterceptType.GetConstructor(new Type[0]));
ilOfCtor.Emit(OpCodes.Stfld, fieldInterceptor);#endregion#region 代理对象定义//---- 实现类对象定义 ----//声明var fieldBeProxy = typeBuilder.DefineField( "_beproxy", ImpType, FieldAttributes.Private);//赋值ilOfCtor.Emit(OpCodes.Ldarg_0);
ilOfCtor.Emit(OpCodes.Newobj, ImpType.GetConstructor(new Type[0]));
ilOfCtor.Emit(OpCodes.Stfld, fieldBeProxy);
ilOfCtor.Emit(OpCodes.Ret);#endregion// ---- 定义类中的方法 ----var methodsOfType = ImpType.GetMethods(BindingFlags.Public | BindingFlags.Instance).Where(a => a.IsVirtual).ToArray();string[] ignoreMethodName = new[] { "GetType", "ToString", "GetHashCode", "Equals" };for (var i = 0; i < methodsOfType.Length; i++)
{#region 方法是否需要拦截判断，Object内置方法过滤bool IsMethodIntercept = false;bool IsTransitinal = false;var method = methodsOfType[i];//---- 过滤Object基类方法,如果是继承，基类中的属性get，set方法也要过滤 ----if (ignoreMethodName.Contains(method.Name) || method.Name.StartsWith("set_") || method.Name.StartsWith("get_"))
{continue;
}// ---- 判断方法是否需要拦截 ----if (isInterceptAllMethod)
{if (method.GetCustomAttribute(typeof(IgnoreInterceptAttibute)) == null)
{
IsMethodIntercept = true;
}
}else{if (method.GetCustomAttribute(typeof(InterceptAttibute)) != null)
{
IsMethodIntercept = true;
}
}// ---- 判断方法是否需要纳入事物管理中 ----if (method.GetCustomAttribute(typeof(Transitional)) != null)
{
IsTransitinal = true;
}#endregion#region 泛型方法处理var methodParameterTypes =
method.GetParameters().Select(p => p.ParameterType).ToArray();// ---- 定义方法名与参数 ----var methodBuilder = typeBuilder.DefineMethod(
method.Name,
MethodAttributes.Public | MethodAttributes.Virtual,
CallingConventions.Standard,
method.ReturnType,
methodParameterTypes);//如果是泛型方法if (method.IsGenericMethod)
{//获取所有泛型参数类型定义Type[] Args = method.GetGenericArguments();
List<string> GenericArgNames = new List<string>();for (int j = 0; j < Args.Length; j++)
{
GenericArgNames.Add(Args[j].Name);
}//代理类方法生成泛型参数定义GenericTypeParameterBuilder[] DGP = methodBuilder.DefineGenericParameters(GenericArgNames.ToArray());//泛型参数约束设置for (int j = 0; j < DGP.Length; j++)
{//泛型参数继承约束DGP[j].SetBaseTypeConstraint(Args[j].BaseType);//泛型参数完成接口约束DGP[j].SetInterfaceConstraints(Args[j].GetInterfaces());
}
}#endregionvar ilOfMethod = methodBuilder.GetILGenerator();var methodresult = ilOfMethod.DeclareLocal(typeof(object)); //instance of result//赋值方法结果对象初始值为nullilOfMethod.Emit(OpCodes.Ldnull);
ilOfMethod.Emit(OpCodes.Stloc_0);#region 事物拦截开始if (IsTransitinal)
{//开始try模块ilOfMethod.BeginExceptionBlock();//调用TransitionManage.StartTransitionilOfMethod.Emit(OpCodes.Call, typeof(TransitionManage).GetMethod("StartTransition"));
ilOfMethod.Emit(OpCodes.Ldarg_0);
}#endregion#region before拦截// ---- before ----if (IsMethodIntercept)
{var parameters = ilOfMethod.DeclareLocal(typeof(object[]));
ilOfMethod.Emit(OpCodes.Ldc_I4, methodParameterTypes.Length);
ilOfMethod.Emit(OpCodes.Newarr, typeof(object));
ilOfMethod.Emit(OpCodes.Stloc, parameters);for (var j = 0; j < methodParameterTypes.Length; j++)
{
ilOfMethod.Emit(OpCodes.Ldloc, parameters);
ilOfMethod.Emit(OpCodes.Ldc_I4, j);
ilOfMethod.Emit(OpCodes.Ldarg, j + 1);
ilOfMethod.Emit(OpCodes.Stelem_Ref);
}
ilOfMethod.Emit(OpCodes.Ldarg_0);
ilOfMethod.Emit(OpCodes.Ldfld, fieldInterceptor);//拦截方法参数赋值if (inheritMode)
{//继承传递代理类本身ilOfMethod.Emit(OpCodes.Ldarg_0);
}else{//接口传递实现类ilOfMethod.Emit(OpCodes.Ldarg_0);
ilOfMethod.Emit(OpCodes.Ldfld, fieldBeProxy);
}
ilOfMethod.Emit(OpCodes.Ldstr, method.Name);
ilOfMethod.Emit(OpCodes.Ldloc, parameters);//调用拦截类中的Before方法ilOfMethod.Emit(OpCodes.Callvirt, InterceptType.GetMethod("Before"));
}#endregion#region 方法执行// ---- call ----////定义实现类局部变量//var localimpobj = ilOfMethod.DeclareLocal(ImpType);////new一个实现类的对象//ilOfMethod.Emit(OpCodes.Newobj, ImpType.GetConstructor(new Type[0]));////局部变量赋值//ilOfMethod.Emit(OpCodes.Stloc, localimpobj);////局部变量出栈，等待调用//ilOfMethod.Emit(OpCodes.Ldloc, localimpobj);//方法执行开始时间var localstart = ilOfMethod.DeclareLocal(typeof(DateTime));
ilOfMethod.Emit(OpCodes.Call, typeof(DateTime).GetMethod("get_Now"));
ilOfMethod.Emit(OpCodes.Stloc, localstart);if (inheritMode)
{//继承方法调用父类的方法ilOfMethod.Emit(OpCodes.Ldarg_0);for (var j = 0; j < methodParameterTypes.Length; j++)
{
ilOfMethod.Emit(OpCodes.Ldarg, j + 1);
}
ilOfMethod.Emit(OpCodes.Call, ImpType.GetMethod(method.Name));
}else{//接口方法调用实现类的方法ilOfMethod.Emit(OpCodes.Ldarg_0);
ilOfMethod.Emit(OpCodes.Ldfld, fieldBeProxy);for (var j = 0; j < methodParameterTypes.Length; j++)
{
ilOfMethod.Emit(OpCodes.Ldarg, j + 1);
}//调用方法ilOfMethod.Emit(OpCodes.Callvirt, ImpType.GetMethod(method.Name));
}var localend = ilOfMethod.DeclareLocal(typeof(DateTime));
ilOfMethod.Emit(OpCodes.Call, typeof(DateTime).GetMethod("get_Now"));
ilOfMethod.Emit(OpCodes.Stloc, localend);#endregion#region after拦截// ---- after ----if (IsMethodIntercept)
{if (method.ReturnType == typeof(void))
{
ilOfMethod.Emit(OpCodes.Ldnull);
}else{
ilOfMethod.Emit(OpCodes.Box, method.ReturnType);
}
ilOfMethod.Emit(OpCodes.Stloc, methodresult);
ilOfMethod.Emit(OpCodes.Ldarg_0);
ilOfMethod.Emit(OpCodes.Ldfld, fieldInterceptor);//拦截方法参数赋值if (inheritMode)
{//继承传递代理类本身ilOfMethod.Emit(OpCodes.Ldarg_0);
}else{//接口传递实现类ilOfMethod.Emit(OpCodes.Ldarg_0);
ilOfMethod.Emit(OpCodes.Ldfld, fieldBeProxy);
}
ilOfMethod.Emit(OpCodes.Ldstr, method.Name);
ilOfMethod.Emit(OpCodes.Ldloc, methodresult);
ilOfMethod.Emit(OpCodes.Ldloc, localstart);
ilOfMethod.Emit(OpCodes.Ldloc, localend);
ilOfMethod.Emit(OpCodes.Callvirt, InterceptType.GetMethod("After"));
}#endregion#region 事物提交及异常捕获及回滚if (IsTransitinal)
{//调用TransitionManage.DoCommitilOfMethod.Emit(OpCodes.Pop);
ilOfMethod.Emit(OpCodes.Call, typeof(TransitionManage).GetMethod("DoCommit"));
ilOfMethod.Emit(OpCodes.Ldarg_0);//开始catch模块ilOfMethod.BeginCatchBlock(typeof(System.Exception));//调用TransitionManage.DoRollBackTransitional transition = (Transitional)method.GetCustomAttribute(typeof(Transitional));if (transition.AutoRollBack)
{
ilOfMethod.Emit(OpCodes.Pop);
ilOfMethod.Emit(OpCodes.Call, typeof(TransitionManage).GetMethod("DoRollBack"));
}else{//throw异常ilOfMethod.Emit(OpCodes.Pop);
ilOfMethod.Emit(OpCodes.Rethrow);
}//结束异常块ilOfMethod.EndExceptionBlock();
}#endregion#region 处理返回值//调用完After方法后,将实现类的方法返回值的临时变量再次压栈用作代理方法的返回ilOfMethod.Emit(OpCodes.Ldloc, methodresult);// pop the stack if return voidif (method.ReturnType == typeof(void))
{
ilOfMethod.Emit(OpCodes.Pop);
}else{if (method.ReturnType.IsValueType)
{
ilOfMethod.Emit(OpCodes.Unbox_Any, method.ReturnType);
}else{
ilOfMethod.Emit(OpCodes.Castclass, method.ReturnType);
}
}#endregion// completeilOfMethod.Emit(OpCodes.Ret);
}
}以上就是NetCore中怎么利用Transitional自定义注解事物，小编相信有部分知识点可能是我们日常工作会见到或用到的。希望你能通过这篇文章学到更多知识。更多详情敬请关注亿速云行业资讯频道。
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