Net Core中使用中间件方式

  首先，创建一个中间件ExceptionMiddleware

public class ExceptionMiddleware
    {
        private readonly RequestDelegate next;
        private IHostingEnvironment environment;

        public ExceptionMiddleware(RequestDelegate next,IHostingEnvironment environment)
        {
            this.next = next;
            this.environment = environment;
        }

        public async Task Invoke(HttpContext context)
        {
            try
            {
                await next.Invoke(context);
                var features = context.Features;
            }
            catch (Exception e)
            {
                await HandleException(context, e);
            }
        }

        private async Task HandleException(HttpContext context, Exception e)
        {
            context.Response.StatusCode = 500;
            context.Response.ContentType = "text/json;charset=utf-8;";
            string error = "";

            if (environment.IsDevelopment())
            {
                var json = new { message = e.Message};
                error = JsonConvert.SerializeObject(json);
            }
            else
                error = "抱歉，出错了";

            await context.Response.WriteAsync(error);
        }
    }

  创建 HandleException(HttpContext context, Exception e) 处理异常，判断是 Development 环境下，输出详细的错误信息，非 Development 环境仅提示调用者“抱歉，出错了”，同时使用 NLog 组件将日志写入硬盘；同样，在 Startup.cs 中将 ExceptionMiddleware 加入管道中

//ExceptionMiddleware 加入管道
app.UseMiddleware<ExceptionMiddleware>();

启动调试,结果如下

{"message":"Attempted to divide by zero."}

  统一封装冷异常处理方式和消息格式，对前端也很友好。