using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
 
namespace AspNetCorePathMapping
{
    public class HomeController : Controller
    {
        private readonly IHostingEnvironment _hostingEnvironment;
 
        public HomeController(IHostingEnvironment hostingEnvironment)
        {
            _hostingEnvironment = hostingEnvironment;
        }
 
        public ActionResult Index()
        {
            string webRootPath = _hostingEnvironment.WebRootPath;
            string contentRootPath = _hostingEnvironment.ContentRootPath;
 
            return Content(webRootPath + "\n" + contentRootPath);
        }
    }
}
通过WebRootPath的使用，基本可以达到Server.MapPath同样的效果。但是这是在controller类中使用。

在普通类库中获取：

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
 
namespace HH.Util
{
    public static class CoreHttpContext
    {        
        private static Microsoft.AspNetCore.Hosting.IHostingEnvironment _hostEnviroment;       
        public static string WebPath => _hostEnviroment.WebRootPath;
 
        public static string MapPath(string path)
        {
            return Path.Combine(_hostEnviroment.WebRootPath, path);
        }
 
        internal static void Configure(Microsoft.AspNetCore.Hosting.IHostingEnvironment hostEnviroment)
        {
            _hostEnviroment = hostEnviroment;
        }
    }
    public static class StaticHostEnviromentExtensions
    {
        public static IApplicationBuilder UseStaticHostEnviroment(this IApplicationBuilder app)
        {
            var webHostEnvironment = app.ApplicationServices.GetRequiredService<Microsoft.AspNetCore.Hosting.IHostingEnvironment>();
            CoreHttpContext.Configure(webHostEnvironment);
            return app;
        }
    }
}

然后在Startup.cs的Configure方法中：

app.UseStaticHostEnviroment();

  只需要将原来的Server.Path替换为CoreHttpContext.MapPath就可以

原文：https://blog.csdn.net/shanghaimoon/article/details/114338839