.net5

概念

 异常过滤器是一种可以在 WebAPI 中捕获那些未得到处理的异常的过滤器，要想创建异常过滤器，你需要实现 IExceptionFilter 接口，不过这种方式比较麻烦，更快捷的方法是直接继承 ExceptionFilterAttribute 并重写里面的 OnException() 方法即可，这是因为 ExceptionFilterAttribute 类本身就实现了 IExceptionFilter 接口

全局

XXX.Common项目下新建自定义异常类：新建文件夹【Custom】新建类：BusinessException.cs【名字自己定义】

using System;

namespace Test.Common.Custom
{
    public class BusinessException : Exception
    {

    }
}

WebApi项目下新建文件夹【Custom/Exception】,在Exception文件夹下新建类：CustomExceptionFilterAttribute

using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.Extensions.Configuration;
using Test.Common.Custom;

namespace Test.WebApi.Custom.Exception
{
    public class CustomExceptionFilterAttribute : ExceptionFilterAttribute
    {
        private readonly IConfiguration _configuration;

        public CustomExceptionFilterAttribute(IConfiguration configuration)
        {
            _configuration = configuration;
        }

        public override void OnException(ExceptionContext context)
        {
            #region 自定义异常
            if (context.Exception.GetType() == typeof(BusinessException))
            {
                ResponseDto response = new ResponseDto()
                {
                    Success = false,
                    Message = context.Exception.Message
                };
                context.Result = new JsonResult(response);
            }
            #endregion

            #region 捕获程序异常，友好提示
            else
            {
                ResponseDto response = new ResponseDto()
                {
                    Success = false,
                    Message = "服务器忙，请稍后再试"
                };
                if (_configuration["AppSetting:DisplayExceptionOrNot"] == "1")
                {
                    response.Message = context.Exception.Message;
                }
                context.Result = new JsonResult(response);
            }
            #endregion
        }
    }
}

Startup中注册

                options.Filters.Add<CustomExceptionFilterAttribute>();

　　

缩小粒度到 Controller 或者 Action 级别

[DatabaseExceptionFilter]
public class EmployeesController : ApiController
{
    //Some code
}

 [CustomExceptionFilter]
 public IEnumerable<string> Get()
 {
    throw new DivideByZeroException(); 
 }