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
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
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().EnableIntercept(); container.Build(); TransitionalMovie tm = container.Resolve (); 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()); } } #endregion var ilOfMethod = methodBuilder.GetILGenerator(); var methodresult = ilOfMethod.DeclareLocal(typeof(object)); //instance of result //赋值方法结果对象初始值为null ilOfMethod.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.StartTransition ilOfMethod.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.DoCommit ilOfMethod.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.DoRollBack Transitional 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 void if (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 // complete ilOfMethod.Emit(OpCodes.Ret); } }