例子：

app.UseExceptionHandler(errorApp =>
{
    errorApp.Run(async context =>
    {
        context.Response.StatusCode = (int)HttpStatusCode.OK;
        context.Response.ContentType = "text/json";
        var exceptionFeature = context.Features.Get<IExceptionHandlerFeature>();
        if (exceptionFeature != null)
        {
            var ex = exceptionFeature.Error.Message + exceptionFeature.Error.StackTrace;
            await context.Response.WriteAsJsonAsync(new Result { ErrorMessage = ex, ResultCode = ResultCode.Error }); ;
        }
    });
});