.NET如何实现一个简单的AOP（面向切面编程）_AOP实现方案详解

public class LogInterceptor : IInterceptor
{
    public void Intercept(IInvocation invocation)
    {
        Console.WriteLine($"开始执行: {invocation.Method.Name}");
        try
        {
            invocation.Proceed(); // 执行原方法
        }
        finally
        {
            Console.WriteLine($"结束执行: {invocation.Method.Name}");
        }
    }
}

// 使用示例
var proxyGenerator = new ProxyGenerator();
var interceptor = new LogInterceptor();
var proxy = proxyGenerator.CreateClassProxy<UserService>(interceptor);
proxy.SaveUser("张三"); // 自动输出前后日志

[AttributeUsage(AttributeTargets.Method)]
public class LogAttribute : Attribute { }

public void Intercept(IInvocation invocation)
{
    var hasLogAttr = invocation.Method.GetCustomAttributes(typeof(LogAttribute), true).Length > 0;
    if (!hasLogAttr)
    {
        invocation.Proceed();
        return;
    }

    Console.WriteLine($"[Log] 开始: {invocation.Method.Name}");
    invocation.Proceed();
    Console.WriteLine($"[Log] 完成: {invocation.Method.Name}");
}

public class UserService
{
    [Log]
    public virtual void SaveUser(string name)
    {
        Console.WriteLine($"保存用户: {name}");
    }
}

public class LoggingAspect : OnMethodBoundaryAspect
{
    public override void OnEntry(MethodExecutionArgs args)
    {
        Console.WriteLine($"进入方法: {args.Method.Name}");
    }

    public override void OnExit(MethodExecutionArgs args)
    {
        Console.WriteLine($"退出方法: {args.Method.Name}");
    }
}

[LoggingAspect]
public void DeleteUser(int id)
{
    // 删除逻辑
}

public class LogActionFilter : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext context)
    {
        Console.WriteLine($"请求开始: {context.ActionDescriptor.DisplayName}");
    }

    public override void OnActionExecuted(ActionExecutedContext context)
    {
        Console.WriteLine($"请求结束: {context.ActionDescriptor.DisplayName}");
    }
}

[LogActionFilter]
public IActionResult GetUser(int id)
{
    return Ok(new { Id = id, Name = "李四" });
}