ASP.NET MVC 异常Exception拦截

一、前言

由于客户端的环境不一致，有可能会造成我们预计不到的异常错误，所以在项目中，友好的异常信息提示，是非常重要的。在asp.net mvc中实现异常属性拦截也非常简单，只需要继承另一个类(System.Web.Mvc.FilterAttribute)和一个接口(System.Web.Mvc.IExceptionFilter)，实现接口里面OnException方法，或者直接继承Mvc 提供的类System.Web.Mvc.HandleErrorAttribute。

二、实现关键逻辑

继承System.Web.Mvc.HandleErrorAttribute，重写了OnException方法，主要实现逻辑代码如下：

  1. public class HandlerErrorAttribute : HandleErrorAttribute
  2. {
  3.     /// <summary>
  4.     /// 控制器方法中出现异常，会调用该方法捕获异常
  5.     /// </summary>
  6.     /// <param name="context">提供使用</param>
  7.     public override void OnException(ExceptionContext context)
  8.     {
  9.         WriteLog(context);
  10.         base.OnException(context);
  11.         context.ExceptionHandled = true;
  12.         if (context.Exception is UserFriendlyException)
  13.         {
  14.             context.HttpContext.Response.StatusCode = (int)HttpStatusCode.OK;
  15.             context.Result = new ContentResult { Content = new AjaxResult { type = ResultType.error, message = context.Exception.Message }.ToJson() };
  16.         }
  17.         else if (context.Exception is NoAuthorizeException)
  18.         {
  19.             context.HttpContext.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
  20.             if (!context.HttpContext.Request.IsAjaxRequest())
  21.             {
  22.                 context.HttpContext.Response.RedirectToRoute("Default", new { controller = "Error", action = "Error401", errorUrl = context.HttpContext.Request.RawUrl });
  23.             }
  24.             else
  25.             {
  26.                 context.Result = new ContentResult { Content = context.HttpContext.Request.RawUrl };
  27.             }
  28.         }
  29.         else
  30.         {
  31.              context.HttpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
  32.              ExceptionMessage error = new ExceptionMessage(context.Exception);
  33.              var s = error.ToJson();
  34.              if (!context.HttpContext.Request.IsAjaxRequest())
  35.              {
  36.                  context.HttpContext.Response.RedirectToRoute("Default", new { controller = "Error", action = "Error500", data = WebHelper.UrlEncode(s) });
  37.              }
  38.              else
  39.              {
  40.                  context.Result = new ContentResult { Content = WebHelper.UrlEncode(s) };
  41.              }
  42.         }
  43.     }
  44.  
  45.     /// <summary>
  46.     /// 写入日志（log4net）
  47.     /// </summary>
  48.     /// <param name="context">提供使用</param>
  49.     private void WriteLog(ExceptionContext context)
  50.     {
  51.         if (context == null)
  52.             return;
  53.         if (context.Exception is NoAuthorizeException || context.Exception is UserFriendlyException)
  54.         {
  55.             //友好错误提示,未授权错误提示，记录警告日志
  56.             LogHelper.Warn(context.Exception.Message);
  57.         }
  58.         else
  59.         {
  60.             //异常错误，
  61.             LogHelper.Error(context.Exception);
  62.  
  63.             ////TODO :写入错误日志到数据库
  64.         }
  65.     }
  66. }

MVC 过滤器全局注册异常拦截:

  1. public class FilterConfig
  2.     {
  3.         public static void RegisterGlobalFilters(GlobalFilterCollection filters)
  4.         {
  5.             filters.Add(new HandlerErrorAttribute());
  6.         }
  7.     }

 

我们看到，context.Exception 分为3种：UserFriendlyException，NoAuthorizeException 或 Exception；UserFriendlyException 是指友好异常，前端友好提示错误信息。NoAuthorizeException 为401未授权异常，当页面未被授权访问时，返回该异常，并携带有未授权的路径地址。其他异常统一返回500错误，并携带异常信息。

 

三、异常处理

 

1.401 未授权错误

 

异常定义代码：

  1. /// <summary>
  2. /// 没有被授权的异常
  3. /// </summary>
  4. public class NoAuthorizeException : Exception
  5. {
  6.     public NoAuthorizeException(string message)
  7.         : base(message)
  8.     {
  9.     }
  10. }

抛出异常代码：

  1. throw new NoAuthorizeException("未授权");

前端UI效果：

 

2.404 未找到页面错误

MVC的404异常处理，有几种方式，我们采用了在Global.asax全局请求函数中处理, 请查看以下代码

  1. protected void Application_EndRequest()
  2.      {
  3.          if (Context.Response.StatusCode == 404)
  4.          {
  5.              bool isAjax = new HttpRequestWrapper(Context.Request).IsAjaxRequest();
  6.              if (isAjax)
  7.              {
  8.                  Response.Clear();
  9.                  Response.Write(Context.Request.RawUrl);
  10.              }
  11.              else
  12.              {
  13.                  Response.RedirectToRoute("Default", new { controller = "Error", action = "Error404", errorUrl = Context.Request.RawUrl });
  14.              }
  15.          }
  16.      }

前端UI效果:

3.500服务器内部错误

 

500异常错误抛出的异常信息对象定义:

  1. /// <summary>
  2. /// 异常错误信息
  3. /// </summary>
  4. [Serializable]
  5. public class ExceptionMessage
  6. {
  7.     public ExceptionMessage()
  8.     {
  9.     }
  10.  
  11.     /// <summary>
  12.     /// 构造函数
  13.     /// 默认显示异常页面
  14.     /// </summary>
  15.     /// <param name="ex">异常对象</param>
  16.     public ExceptionMessage(Exception ex)
  17.         :this(ex, true)
  18.     {
  19.  
  20.     }
  21.     /// <summary>
  22.     /// 构造函数
  23.     /// </summary>
  24.     /// <param name="ex">异常对象</param>
  25.     /// <param name="isShowException">是否显示异常页面</param>
  26.     public ExceptionMessage(Exception ex, bool isShowException)
  27.     {
  28.         MsgType = ex.GetType().Name;
  29.         Message = ex.InnerException != null ? ex.InnerException.Message : ex.Message;
  30.         StackTrace = ex.StackTrace.Length > 300 ? ex.StackTrace.Substring(0, 300) : ex.StackTrace;
  31.         Source = ex.Source;
  32.         Time = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
  33.         Assembly = ex.TargetSite.Module.Assembly.FullName;
  34.         Method = ex.TargetSite.Name;
  35.  
  36.         ShowException = isShowException;
  37.         var request = HttpContext.Current.Request;
  38.         IP = Net.Ip;
  39.         UserAgent = request.UserAgent;
  40.         Path = request.Path;
  41.         HttpMethod = request.HttpMethod;
  42.     }
  43.     /// <summary>
  44.     /// 消息类型
  45.     /// </summary>
  46.     public string MsgType { get; set; }
  47.  
  48.     /// <summary>
  49.     /// 消息内容
  50.     /// </summary>
  51.     public string Message { get; set; }
  52.  
  53.     /// <summary>
  54.     /// 请求路径
  55.     /// </summary>
  56.     public string Path { get; set; }
  57.  
  58.     /// <summary>
  59.     /// 程序集名称
  60.     /// </summary>
  61.     public string Assembly { get; set; }
  62.  
  63.     /// <summary>
  64.     /// 异常参数
  65.     /// </summary>
  66.     public string ActionArguments { get; set; }
  67.  
  68.     /// <summary>
  69.     /// 请求类型
  70.     /// </summary>
  71.     public string HttpMethod { get; set; }
  72.  
  73.     /// <summary>
  74.     /// 异常堆栈
  75.     /// </summary>
  76.     public string StackTrace { get; set; }
  77.  
  78.     /// <summary>
  79.     /// 异常源
  80.     /// </summary>
  81.     public string Source { get; set; }
  82.  
  83.     /// <summary>
  84.     /// 服务器IP 端口
  85.     /// </summary>
  86.     public string IP { get; set; }
  87.  
  88.     /// <summary>
  89.     /// 客户端浏览器标识
  90.     /// </summary>
  91.     public string UserAgent { get; set; }
  92.  
  93.  
  94.     /// <summary>
  95.     /// 是否显示异常界面
  96.     /// </summary>
  97.     public bool ShowException { get; set; }
  98.  
  99.     /// <summary>
  100.     /// 异常发生时间
  101.     /// </summary>
  102.     public string Time { get; set; }
  103.  
  104.     /// <summary>
  105.     /// 异常发生方法
  106.     /// </summary>
  107.     public string Method { get; set; }
  108. }

抛出异常代码：

  1. throw new Exception("出错了");

前端UI效果：

4. UserFriendlyException 友好异常

 

异常定义代码：

  1. /// <summary>
  2. /// 用户友好异常
  3. /// </summary>
  4. public class UserFriendlyException : Exception
  5. {
  6.     public UserFriendlyException(string message)
  7.         : base(message)
  8.     {
  9.     }
  10. }

在异常拦截关键代码中，我们发现友好异常（UserFriendlyException）其实是返回了一个结果对象AjaxResult，

AjaxResult对象的定义：

  1. /// <summary>
  2.     /// 表示Ajax操作结果
  3.     /// </summary>
  4.     public class AjaxResult
  5.     {
  6.         /// <summary>
  7.         /// 获取 Ajax操作结果类型
  8.         /// </summary>
  9.         public ResultType type { get; set; }
  10.  
  11.         /// <summary>
  12.         /// 获取 Ajax操作结果编码
  13.         /// </summary>
  14.         public int errorcode { get; set; }
  15.  
  16.         /// <summary>
  17.         /// 获取 消息内容
  18.         /// </summary>
  19.         public string message { get; set; }
  20.  
  21.         /// <summary>
  22.         /// 获取 返回数据
  23.         /// </summary>
  24.         public object resultdata { get; set; }
  25.     }
  26.     /// <summary>
  27.     /// 表示 ajax 操作结果类型的枚举
  28.     /// </summary>
  29.     public enum ResultType
  30.     {
  31.         /// <summary>
  32.         /// 消息结果类型
  33.         /// </summary>
  34.         info = 0,
  35.  
  36.         /// <summary>
  37.         /// 成功结果类型
  38.         /// </summary>
  39.         success = 1,
  40.  
  41.         /// <summary>
  42.         /// 警告结果类型
  43.         /// </summary>
  44.         warning = 2,
  45.  
  46.         /// <summary>
  47.         /// 异常结果类型
  48.         /// </summary>
  49.         error = 3
  50.     }

 

四、Ajax请求异常时处理

 

在异常拦截的关键代码中，我们有看到，如果是ajax请求时，是执行不同的逻辑，这是因为ajax的请求，不能直接通过MVC的路由跳转，在请求时必须返回结果内容

然后在前端ajax的方法中，统一处理返回的错误，以下是我们项目中用到的ajax封装，对异常错误，进行了统一处理。

  1. (function ($) {
  2.     "use strict";
  3.  
  4.     $.httpCode = {
  5.         success: "1",
  6.         fail: "3",
  7.     };
  8.     // http 通信异常的时候调用此方法
  9.     $.httpErrorLog = function (msg) {
  10.         console.log('=====>' + new Date().getTime() + '<=====');
  11.         console.log(msg);
  12.     };
  13.  
  14.     // ajax请求错误处理
  15.     $.httpError = function (xhr, textStatus, errorThrown) {
  16.  
  17.         if (xhr.status == 401) {
  18.             location.href = "/Error/Error401?errorUrl=" + xhr.responseText;
  19.         }
  20.  
  21.         if (xhr.status == 404) {
  22.             location.href = "/Error/Error404?errorUrl=" + xhr.responseText;
  23.         }
  24.  
  25.         if (xhr.status == 500) {
  26.             location.href = "/Error/Error500?data=" + xhr.responseText;
  27.         }
  28.     };
  29.  
  30.     /* get请求方法（异步）:
  31.     * url地址, param参数, callback回调函数 beforeSend 请求之前回调函数, complete 请求完成之后回调函数
  32.     * 考虑到get请求一般将参数与url拼接一起传递，所以将param参数放置最后
  33.     * 返回AjaxResult结果对象
  34.     */
  35.     $.httpAsyncGet = function (url, callback, beforeSend, complete, param) {
  36.         $.ajax({
  37.             url: url,
  38.             data: param,
  39.             type: "GET",
  40.             dataType: "json",
  41.             async: true,
  42.             cache: false,
  43.             success: function (data) {
  44.                 if ($.isFunction(callback)) callback(data);
  45.             },
  46.             error: function (XMLHttpRequest, textStatus, errorThrown) {
  47.                 $.httpError(XMLHttpRequest, textStatus, errorThrown);
  48.             },
  49.             beforeSend: function () {
  50.                 if (!!beforeSend) beforeSend();
  51.             },
  52.             complete: function () {
  53.                 if (!!complete) complete();
  54.             }
  55.         });
  56.     };
  57.  
  58.     /* get请求方法（同步）:
  59.     * url地址,param参数
  60.     * 返回实体数据对象
  61.     */
  62.     $.httpGet = function (url, param) {
  63.         var res = {};
  64.         $.ajax({
  65.             url: url,
  66.             data: param,
  67.             type: "GET",
  68.             dataType: "json",
  69.             async: false,
  70.             cache: false,
  71.             success: function (data) {
  72.                 res = data;
  73.             },
  74.             error: function (XMLHttpRequest, textStatus, errorThrown) {
  75.                 $.httpError(XMLHttpRequest, textStatus, errorThrown);
  76.             },
  77.         });
  78.         return res;
  79.     };
  80.  
  81.     /* post请求方法（异步）:
  82.     * url地址, param参数, callback回调函数 beforeSend 请求之前回调函数, complete 请求完成之后回调函数
  83.     * 返回AjaxResult结果对象
  84.     */
  85.     $.httpAsyncPost = function (url, param, callback, beforeSend, complete) {
  86.         $.ajax({
  87.             url: url,
  88.             data: param,
  89.             type: "POST",
  90.             dataType: "json",
  91.             async: true,
  92.             cache: false,
  93.             success: function (data) {
  94.                 if ($.isFunction(callback)) callback(data);
  95.             },
  96.             error: function (XMLHttpRequest, textStatus, errorThrown) {
  97.                 $.httpError(XMLHttpRequest, textStatus, errorThrown);
  98.             },
  99.             beforeSend: function () {
  100.                 if (!!beforeSend) beforeSend();
  101.             },
  102.             complete: function () {
  103.                 if (!!complete) complete();
  104.             }
  105.         });
  106.     };
  107.  
  108.     /* post请求方法（同步）:
  109.     * url地址,param参数, callback回调函数
  110.     * 返回实体数据对象
  111.     */
  112.     $.httpPost = function (url, param, callback) {
  113.         $.ajax({
  114.             url: url,
  115.             data: param,
  116.             type: "POST",
  117.             dataType: "json",
  118.             async: false,
  119.             cache: false,
  120.             success: function (data) {
  121.                 if ($.isFunction(callback)) callback(data);
  122.             },
  123.             error: function (XMLHttpRequest, textStatus, errorThrown) {
  124.                 $.httpError(XMLHttpRequest, textStatus, errorThrown);
  125.             },
  126.         });
  127.     },
  128.  
  129.     /* ajax异步封装:
  130.     * type 请求类型, url地址, param参数, callback回调函数
  131.     * 返回实体数据对象
  132.     */
  133.     $.httpAsync = function (type, url, param, callback) {
  134.         $.ajax({
  135.             url: url,
  136.             data: param,
  137.             type: type,
  138.             dataType: "json",
  139.             async: true,
  140.             cache: false,
  141.             success: function (data) {
  142.                 if ($.isFunction(callback)) callback(data);
  143.             },
  144.             error: function (XMLHttpRequest, textStatus, errorThrown) {
  145.                 $.httpError(XMLHttpRequest, textStatus, errorThrown);
  146.             },
  147.         });
  148.     };
  149. })(jQuery);

 

五、总结

至此，我们发现其实MVC的异常处理，真的很简单，只需要在过滤器中全局注册之后，然后重写OnException的方法，实现逻辑即可。关键是在于项目中Ajax请求，需要用统一的封装方法。

posted @ 2018-07-01 15:48  沉淀的风  阅读(7295)  评论(2)  编辑  收藏  举报