.NET CORE全局异常处理(自定义过滤器 ExceptionFilterAttribute、自定义中间件)

1、自定义中间件处理异常(推荐) 参考：https://www.csframework.com/archive/1/arc-1-20211230-4180.htm

using System.Net;
using System.Text.Json;
using ExceptionHandling.Models.Responses;

namespace ExceptionHandling.Middlewares;

public class ExceptionHandlingMiddleware
{
    private readonly RequestDelegate _next;  // 用来处理上下文请求  
    private readonly ILogger<ExceptionHandlingMiddleware> _logger;
    public ExceptionHandlingMiddleware(RequestDelegate next,ILogger<ExceptionHandlingMiddleware> logger)
    {
        _next = next;
        _logger = logger;
    }

    public async Task InvokeAsync(HttpContext httpContext)
    {
        try
        {
            await _next(httpContext); //要么在中间件中处理，要么被传递到下一个中间件中去
        }
        catch (Exception ex)
        {
            await HandleExceptionAsync(httpContext, ex); // 捕获异常了在HandleExceptionAsync中处理
        }
    }
    private async Task HandleExceptionAsync(HttpContext context, Exception exception)
    {
        context.Response.ContentType = "application/json";  // 返回json 类型
        var response = context.Response;

        var errorResponse = new ErrorResponse
        {
            Success = false
        };  // 自定义的异常错误信息类型
        switch (exception)
        {
            case ApplicationException ex:
                if (ex.Message.Contains("Invalid token"))
                {
                    response.StatusCode = (int) HttpStatusCode.Forbidden;
                    errorResponse.Message = ex.Message;
                    break;
                }
                response.StatusCode = (int) HttpStatusCode.BadRequest;
                errorResponse.Message = ex.Message;
                break;
            case KeyNotFoundException ex:
                response.StatusCode = (int) HttpStatusCode.NotFound;
                errorResponse.Message = ex.Message;
                break;
            default:
                response.StatusCode = (int) HttpStatusCode.InternalServerError;
                errorResponse.Message = "Internal Server errors. Check Logs!";
                break;
        }
        _logger.LogError(exception.Message);
        var result = JsonSerializer.Serialize(errorResponse);
        await context.Response.WriteAsync(result);
    }
} 

注入中间件：app.UseMiddleware<ExceptionHandlingMiddleware>();然后在Action或者Service中直接抛异常，就会走异常处理。
2、使用过滤器 参考：https://blog.csdn.net/Daniel_yka/article/details/121062319

public class CustomExceptionFilterAttribute: ExceptionFilterAttribute
{
  private readonly ILogger<WeatherForecastController> _logger;
  public CustomExceptionFilterAttribute(ILogger<WeatherForecastController> logger)
  {
    _logger = logger;
  }
  public override void OnException(ExceptionContext context)
  {
    //判断该异常有没有处理
    if (!context.ExceptionHandled)
    {
      _logger.LogError($"Path:{context.HttpContext.Request.Path}Message:{context.Exception.Message}");
      context.Result = new JsonResult(new {Reslut = false,Msg = "发生异常，请联系管理员"});
      context.ExceptionHandled = true;
    }
  }
}

然后再在Startup下面的ConfigureServices注册这个类:services.AddControllers(o=>o.Filters.Add(typeof(CustomExceptionFilterAttribute)));
此时当程序中有异常，便会进入该方法，我们就能在这里统一管理异常。