简单介绍ASP.NET Core实现文件上传和下载

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导读这篇文章主要为大家详细介绍了ASP.NET Core实现文件上传和下载，文中示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下本文实例为大家分享了ASP.NET Core实现文件上传和下载的具体代码，供大家参考，具体内容如下
一、文件上传1.1 获取文件后缀

/// < summary>
/// 获取文件后缀
/// < /summary>
/// < param name="fileName">文件名称< /param>
/// < returns>
    public async static TaskGetFileSuffixAsync(string fileName)
    {
      return await Task.Run(() =>
      {
        string suffix = Path.GetExtension(fileName);
        return suffix;
      });
    }

1.2 上传单文件

public class FileMessage
  {
    /// < summary>
    /// 原文件名称
    /// < /summary>
    public string FileName { get; set; }
 
    /// < summary>
    /// 附件名称(协议或其他要进行数据库保存与模型绑定的命名)
    /// < /summary>
    public string ArgumentName { get; set; }
 
    /// < summary>
    /// 文件大小(KB)
    /// < /summary>
    public string FileSize { get; set; }
 
    /// < summary>
    /// -1：上传失败 0：等待上传 1：已上传
    /// < /summary>
    public int FileStatus { get; set; }
 
    /// < summary>
    /// 上传结果
    /// < /summary>
    public string UploadResult { get; set; }
 
    /// < summary>
    /// 创建实例
    /// < /summary>
    /// < param name="fileName">原文件名称< /param>
    /// < param name="argumentName">(新)附件名称< /param>
    /// < param name="fileSize">大小< /param>
    /// < param name="fileStatus">文件状态< /param>
    /// < returns>< /returns>
    public static FileMessage CreateNew(string fileName,
      string argumentName,
      string fileSize,
      int fileStatus,
      string uploadResult)
    {
      return new FileMessage()
      {
        FileName = fileName,
        ArgumentName = argumentName,
        FileSize = fileSize,
        FileStatus = fileStatus,
        UploadResult = uploadResult
      };
    }
  }

/// < summary>
/// 上传文件
 /// < /summary>
 /// < param name="file">上传的文件< /param>
 /// < param name="fold">要存储的文件夹< /param>
 /// < returns>< /returns>
    public async static TaskUploadFileAsync(IFormFile file, string fold)
    {
      string fileName = file.FileName;
      string path = Directory.GetCurrentDirectory() + @"/Upload/" + fold + "/";
      if (!Directory.Exists(path))
      {
        Directory.CreateDirectory(path);
      }
      string argumentName = DateTime.Now.ToString("yyyyMMddHHmmssfff") + await GetFileSuffixAsync(file.FileName);
      string fileSize = Math.Round((decimal)file.Length / 1024, 2) + "k";
      string filePath = Path.Combine(path, argumentName);
      try
      {
        using (FileStream stream = new FileStream(filePath, FileMode.Create))
        {
          await file.CopyToAsync(stream);
        }
        return FileMessage.CreateNew(fileName, argumentName, fileSize, 1, "文件上传成功");
      }
      catch (Exception e)
      {
        return FileMessage.CreateNew(fileName, argumentName, fileSize, -1, "文件上传失败：" + e.Message);
      }
    }

1.3 上传多文件

/// < summary>
/// 上传多文件
/// < /summary>
/// < param name="files">上传的文件集合< /param>
/// < param name="fold">要存储的文件夹< /param>
/// < returns>< /returns>
    public async static Task<1list> UploadFilesAsync(IFormFileCollection files, string fold)
    {
      string path = Directory.GetCurrentDirectory() + @"/Upload/" + fold + "/";
      if (!Directory.Exists(path))
      {
        Directory.CreateDirectory(path);
      }
      Listmessages = new List();
      foreach (var file in files)
      {
        string fileName = file.FileName;
        string argumentName = DateTime.Now.ToString("yyyyMMddHHmmssfff") + await GetFileSuffixAsync(file.FileName);
        string fileSize = Math.Round((decimal)file.Length / 1024, 2) + "k";
        string filePath = Path.Combine(path, argumentName);
        try
        {
          using (FileStream stream = new FileStream(filePath, FileMode.Create))
          {
            await file.CopyToAsync(stream);
          }
          messages.Add(FileMessage.CreateNew(fileName, argumentName, fileSize, 1, "文件上传成功"));
        }
        catch (Exception e)
        {
          messages.Add(FileMessage.CreateNew(fileName, argumentName, fileSize, -1, "文件上传失败，失败原因：" + e.Message));
        }
      }
      return messages;
    }

[Route("api/[controller]")]
  [ApiController]
  public class ManageProtocolFileController : ControllerBase
  {
    private readonly string createName = "";
    private readonly IWebHostEnvironment _env;
    private readonly ILogger_logger;
    public ManageProtocolFileController(IWebHostEnvironment env,
      ILoggerlogger)
    {
      _env = env;
      _logger = logger;
    }
     
    /// < summary>
    /// 协议上传附件
    /// < /summary>
    /// < param name="file">< /param>
    /// < returns>< /returns>
    [HttpPost("upload")]
    public async TaskUploadProtocolFile([FromForm] IFormFile file)
    {
      return await UploadFileAsync(file, "ManageProtocol");
    }
  }

二、文件下载2.1 获取ContentType属性

/// < summary>
/// 获取文件ContentType
/// < /summary>
/// < param name="fileName">文件名称< /param>
 /// < returns>< /returns>
    public async static TaskGetFileContentTypeAsync(string fileName)
    {
      return await Task.Run(() =>
      {
        string suffix = Path.GetExtension(fileName);
        var provider = new FileExtensionContentTypeProvider();
        var contentType = provider.Mappings[suffix];
        return contentType;
      });
    }

2.2 执行下载

[Route("api/[controller]")]
[ApiController]
  public class ManageProtocolFileController : ControllerBase
  {
    private readonly string createName = "";
    private readonly IWebHostEnvironment _env;
    private readonly ILogger_logger;
    public ManageProtocolFileController(IWebHostEnvironment env,
      ILoggerlogger)
    {
      _env = env;
      _logger = logger;
    }
     
    /// < summary>
    /// 下载附件
    /// < /summary>
    /// < param name="fileName">文件名称
    /// < returns>< /returns>
    [HttpGet("download")]
    public async TaskDownload([FromQuery] string fileName)
    {
      try
      {
        string rootPath = _env.ContentRootPath + @"/Upload/ManageProtocolFile";
        string filePath = Path.Combine(rootPath, fileName);
        var stream = System.IO.File.OpenRead(filePath);
        string contentType = await GetFileContentTypeAsync(fileName);
        _logger.LogInformation("用户:" + createName + "下载后台客户协议附件:" + request.FileName);
        return File(stream, contentType, fileName);
      }
      catch (Exception e)
      {
        _logger.LogError(e, "用户:" + createName + "下载后台客户协议附件出错，出错原因:" + e.Message);
        throw new Exception(e.ToString());
      }
    }
}

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