与web api类似，asp.net core web mvc模板也是利用ExceptionHandler来处理错误，在starup的Configure配置数据发生时导向的/home/error

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env){if (env.IsDevelopment()){app.UseDeveloperExceptionPage();}else{app.UseExceptionHandler("/Home/Error");app.UseHsts();}//处理404数据的显示信息app.UseStatusCodePages(async context =>{context.HttpContext.Response.ContentType = "text/plain";await context.HttpContext.Response.WriteAsync($"找不到资源，状态码: {context.HttpContext.Response.StatusCode}");});//……}

异常业务类定义如下

using System;
namespace WebError
{/// <summary>/// 产品异常/// </summary>public class DaMeiException : ApplicationException{/// <summary>/// /// </summary>/// <param name="message"></param>public DaMeiException(string message) : base(message){}}/// <summary>/// His项目异常/// </summary>public class HisException : DaMeiException{/// <summary>/// /// </summary>/// <param name="message"></param>public HisException(string message) : base(message){}}/// <summary>/// Lis项目异常/// </summary>public class LisException : DaMeiException{/// <summary>/// /// </summary>/// <param name="message"></param>public LisException(string message) : base(message){}}/// <summary>/// 模块异常/// </summary>public class RegisteredException : HisException{/// <summary>/// /// </summary>/// <param name="message"></param>public RegisteredException(string message) : base(message){}}
}

Controller.cs中，因为web mvc是有view的，所以把错误返回到ErrorViewModel到View前端进行显示。同样，业务异常类DaMeiException作为错误分类处理的标志，从而完成异常的分类处理。

        public IActionResult Privacy(){var ran = new Random();switch (ran.Next(1, 4)){case 1:int i = 0;var j = 10 / i;return Ok();case 2:throw new RegisteredException("这是一个错误");default:return View();}}[ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]public IActionResult Error(){var context = HttpContext.Features.Get<IExceptionHandlerFeature>();       //如果是业务自定义异常，进行特殊处理if (context.Error is DaMeiException){return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier, ErrorMessage = context.Error.Message, ErrorType = "His" });}else{return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier, ErrorMessage = context.Error.Message, ErrorType = "System" });}}

Error.schtml 完成具体数据的展示  

@model ErrorViewModel
@{ViewData["Title"] = "错误";
}
<h1 class="text-danger">错误</h1>
<h2 class="text-danger">一个请求处理错误</h2>
@if (Model.ShowRequestId)
{<h3>@Model.ErrorType</h3><p><strong>请求ID:</strong> <code>@Model.RequestId</code></p><p>@Model.ErrorMessage</p>
}

       每个框都有处理异常的方式，关键是要设计好业务系统中的异常关系，标准化异常处理的流程和格式，方便日志，监控系统采集汇总这些异常，为系统稳定提供保驾护航。

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