JAVA高级面试进阶训练营视频教程

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□ 接口

public interface IExceptionFilter
{
    void OnException(ExceptionContext filterContext);
}

ExceptionContext继承于ControllerContext,从中可以获得路由数据route data、HttpContext。

 

□ 的HandleErrorAttribute是对IExceptionFilter的实现，默认是启用的

public static void RegisterGlobalFilters(GlobalFiltersCollection filters)
{
    filters.Add(new HandleErrorAttribute());
}

 

  使用默认的HandleErrorAttribute

□ 让Shared/Error.cshtml的出错页报错

前提是，在Web.config中配置：

<customErrors mode="On"></customErrors>

 

□ 根据不同错误类型显示不同的错误页

        [HandleError(ExceptionType = typeof(DbException),View = "")]
        [HandleError(ExceptionType = typeof(ApplicationException), View = "")]
        public ActionResult SomeAction()

 

□ HandleErrorAttribute的不足之处

1、只是显示错误页，无法记录错误日志
2、只能捕获500错误
3、不能捕获Controller以外的错误

 

  继承HandleErrorAttribute自定义异常处理

使用log4net记录错误日志，并能记录AJAX错误，返回状态码为500的服务端错误。

 

需要一个显示错误信息的类：

namespace MvcApplication1.Models
{
    public class HandleErrorInfo
    {
        public HandleErrorInfo(Exception exception, string actionName, string controllerName)
        {
            this.Exception = exception;
            this.ControllerName = controllerName;
            this.ActionName = actionName;
        }
        public string ActionName { get; set; }
        public string ControllerName { get; set; }
        public Exception Exception { get; set; }
    }
}

 

引用log4net组件，继承HandleErrorAttribute自定义异常，使之能记录状态码为500的服务端错误，并能以json形式返回ajax相关异常。

using System.Web;

using System.Web.Mvc;

using log4net;

namespace MvcApplication1.Extension

{

    public class PowerfulHandleErrorAttribute : HandleErrorAttribute

    {

        private readonly ILog _logger;

        public PowerfulHandleErrorAttribute()

        {

            _logger = LogManager.GetLogger("MyLogger");

        }

        public override void OnException(ExceptionContext filterContext)

        {

            if (filterContext.ExceptionHandled || !filterContext.HttpContext.IsCustomErrorEnabled)

            {

                return;

            }

            if (new HttpException(null, filterContext.Exception).GetHttpCode() != 500)

            {

                return;

            }

            if (!ExceptionType.IsInstanceOfType(filterContext.Exception))

            {

                return;

            }

            //如果是AJAX请求返回json

            if (filterContext.HttpContext.Request.Headers["X-Requested-With"] == "XMLHttpRequest")

            {

                filterContext.Result = new JsonResult()

                {

                    JsonRequestBehavior = JsonRequestBehavior.AllowGet,

                    Data = new

                    {

                        error = true,

                        message = filterContext.Exception.Message

                    }

                };

            }

            else

            {

                var controllerName = (string)filterContext.RouteData.Values["controller"];

                var actionName = (string)filterContext.RouteData.Values["action"];

                var model = new HandleErrorInfo(filterContext.Exception, controllerName, actionName);

                filterContext.Result = new ViewResult()

                {

                    ViewName = View,

                    MasterName = Master,

                    ViewData = new ViewDataDictionary(model),

                    TempData = filterContext.Controller.TempData

                };

            }

            _logger.Error(filterContext.Exception.Message, filterContext.Exception);

            filterContext.ExceptionHandled = true;

            filterContext.HttpContext.Response.Clear();

            filterContext.HttpContext.Response.StatusCode = 500;

            filterContext.HttpContext.Response.TrySkipIisCustomErrors = true;

        }

    }

}

 

以上PowerfulHandleErrorAttribute错误，只能处理服务端状态码500错误。还可以在全局中设置：当出现HttpException异常的时候，返回对应的错误提醒视图。

       //处理filter遗漏的错误

        protected void Application_Error(object sender, EventArgs e)

        {

            var httpContext = ((MvcApplication) sender).Context;

            var currentRouteData = RouteTable.Routes.GetRouteData(new HttpContextWrapper(httpContext));

            var currentController = "";

            var currentAction = "";

            if (currentRouteData != null)

            {

                if (currentRouteData.Values["controller"] != null &&

                    !string.IsNullOrEmpty(currentRouteData.Values["controller"].ToString()))

                {

                    currentController = currentRouteData.Values["controller"].ToString();

                }

                if (currentRouteData.Values["action"] != null &&

                    !string.IsNullOrEmpty(currentRouteData.Values["action"].ToString()))

                {

                    currentAction = currentRouteData.Values["action"].ToString();

                }

            }

            var ex = Server.GetLastError();

            var controller = new ErrorController();

            var routeData = new RouteData();

            var action = "Index";

            if (ex is HttpException)

            {

                var httpEx = ex as HttpException;

                switch (httpEx.GetHttpCode())

                {

                    case 404:

                        action = "NotFound";

                        break;

                    default:

                        action = "Index";

                        break;

                }

            }

            httpContext.ClearError();

            httpContext.Response.Clear();

            httpContext.Response.StatusCode = ex is HttpException ? ((HttpException) ex).GetHttpCode() : 500;

            httpContext.Response.TrySkipIisCustomErrors = true;

            routeData.Values["controller"] = "Error";

            routeData.Values["action"] = action;

            controller.ViewData.Model = new HandleErrorInfo(ex, currentController, currentAction);

            ((IController)controller).Execute(new RequestContext(new HttpContextWrapper(httpContext), routeData));

        }

 

为此，还需要定义一个ErrorController，当然还有与之对应的错误提示视图:

using System.Web.Mvc;

namespace MvcApplication1.Controllers

{

    public class ErrorController : Controller

    {

        public ActionResult Index()

        {

            return View();

        }

        public ActionResult NotFound()

        {

            return View();

        }

    }

}

 

  使用ELMAH记录全局异常

using System.Web.Mvc;

using Elmah;

namespace MvcApplication1.Extension

{

    public class ElmahHandleErrorAttribute : HandleErrorAttribute

    {

        public override void OnException(ExceptionContext filterContext)

        {

            base.OnException(filterContext);

            if (filterContext.ExceptionHandled)

            {

                ErrorSignal.FromCurrentContext().Raise(filterContext.Exception);

            }

        }

    }

}

 

参考资料：
Exception Handling in ASP.NET MVC