netcore3.1 跨域请求

services.AddCors(options => options.AddPolicy("AllowCors",
                            builder => builder.AllowAnyOrigin()
                            .WithMethods("GET", "POST", "HEAD", "PUT", "DELETE", "OPTIONS")));


app.UseMiddleware<ExceptionMiddleware>();
            app.UseCors("AllowCors");
            app.UseHttpsRedirection();
            app.UseStaticFiles();

  app.UseCors("AllowCors")这个方法最好放在

app.UseHttpsRedirection()前面