1、安装Nuget依赖包：Microsoft.AspNetCore.StaticFiles
2、在Program.cs中注册中间件

app.UseStaticFiles();

3、将业务接口和实现类在Program.cs中注入到运行时

builder.Services.AddScoped<IModelServive,ModelServiveImpl>();

4、新建IModelServive接口，用于获取文件类型

using Microsoft.AspNetCore.Mvc;

namespace digitization_model.Service;

public interface IModelServive
{
    String getFileType(String fileName);
}

5、定义接口实现类

using System.Net;
using Microsoft.AspNetCore.Http.HttpResults;
using Microsoft.AspNetCore.Mvc;

namespace digitization_model.Service.Impl;

public class ModelServiveImpl : IModelServive
{
    public String getFileType(String fileName)
    {
        String extension = Path.GetExtension(fileName).ToLowerInvariant();
        switch (extension)
        {
            case ".txt": return "text/plain";
            case ".html": return "text/html";
            case ".pdf": return "application/pdf";
            case ".doc": case ".docx": return "application/msword";
            case ".xls": case ".xlsx": return "application/vnd.ms-excel";
            // 添加更多类型...
            default: return "application/octet-stream";
        }
    }
}

6、定义控制器

using System.Runtime.InteropServices.JavaScript;
using digitization_model.Service;
using Microsoft.AspNetCore.Mvc;

namespace digitization_model.Controller;

[ApiController]
[Route("[controller]")]
public class ModelController : ControllerBase
{
    private readonly IModelServive modelServive;
    private readonly IWebHostEnvironment _env;
    

    public ModelController(IModelServive modelServive,IWebHostEnvironment _env)
    {
        this.modelServive = modelServive;
        this._env = _env;
    }

    
    
    [HttpGet("getFileUrl/modelFilePath/{modelFilePath}/fileName/{fileName}")]
    public IActionResult getFileUrl(String modelFilePath,String fileName)
    {
        try
        {
            string filePath = Path.Combine(_env.WebRootPath+"/"+modelFilePath, fileName);

            if (!System.IO.File.Exists(filePath))
            {
                return NotFound(); // 如果文件不存在，返回404
            }
            // 获取文件类型并设置Content-Type
            string contentType = modelServive.getFileType(fileName);

            // 读取文件内容并作为附件发送，以便浏览器决定如何处理（预览或下载）
            var fileStream = new FileStream(filePath, FileMode.Open);
            return File(fileStream, contentType, fileName);
        }
        catch (Exception ex)
        {
            // 记录异常或处理错误
            return StatusCode(StatusCodes.Status500InternalServerError, ex.Message);
        }
    }
    
}