UseExceptionHandler

app.UseExceptionHandler(configure =>
{
    configure.Run(async context =>
    {
        var exHeader = context.Features.Get<IExceptionHandlerPathFeature>();
        var ex = exHeader.Error;
        if (ex != default)
        {
            await context.Response.WriteAsJsonAsync(new { code = 500, errPath = exHeader.Path, msg = $"服务器内部错误->{ex.Message}" });
        }

    });
});

自定义中间件

app.UseMiddleware<ErrorHandlingMiddleware>();

using Newtonsoft.Json;
using System.Collections.Generic;
using System.Net;

namespace TouristRouteWebApplaction.Middleware
{
    public class ErrorHandlingMiddleware
    {
        private readonly RequestDelegate next;
        public ErrorHandlingMiddleware(RequestDelegate next)
        {
            this.next = next;
        }
        public async Task Invoke(HttpContext context /* other dependencies */)
        {
            try
            {
                await next(context);
            }
            catch (Exception ex)
            {
                await HandleExceptionAsync(context, ex);
            }
        }
        private static Task HandleExceptionAsync(HttpContext context, Exception ex)
        {
            var code = HttpStatusCode.InternalServerError; // 500 if unexpected
            if (ex is KeyNotFoundException) code = HttpStatusCode.NotFound;
            //else if (ex is MyUnauthorizedException) code = HttpStatusCode.Unauthorized;
            //else if (ex is MyException) code = HttpStatusCode.BadRequest;
            var result = JsonConvert.SerializeObject(new { error = ex.Message });//JsonConvert.SerializeObject(errorObj, opts.Value.SerializerSettings)
            context.Response.ContentType = "application/json";
            context.Response.StatusCode = (int)code;
            return context.Response.WriteAsync(result);
        }
    }
}