ftp文件下载

最新推荐文章于 2020-12-30 18:37:23 发布

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#asp.net #c# #ftp

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该博客介绍了如何使用C#编程实现FTP文件下载。通过`FtpWebRequest`类连接FTP服务器，设置登录凭据，下载文件并将其保存到本地。提供了一个名为`FtpFile`的类，包含初始化FTP参数、下载文件以及格式化目录的方法。

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using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;

namespace GasMap.Common
{
    public class FtpFile
    {
        private string ftpUserName;
        private string ftpPassword;
        /// <summary>
        /// 连接服务器
        /// </summary>
        /// <param name="server">服务器地址（IP）</param>
        /// <param name="userName">登录名</param>
        /// <param name="pwd">密码</param>
        /// <returns></returns>
        public void InitFtpParam(string userName, string pwd)
        {
            ftpUserName = userName;
            ftpPassword = pwd;
        }
        /// <summary>
        /// 下载文件
        /// </summary>
        /// <param name="ftpDir">ftp文件目录</param>
        /// <param name="fileName">文件名</param>
        /// <returns>文件buffer</returns>
        public bool DownloadFile(string ftpDir, string fileName, string localDir)
        {
            FtpWebRequest reqFTP;

            try
            {
                // 如果文件存在，则覆盖，否则创建文件
                string ftpFileName = FolderFormat(ftpDir, '/') + fileName;
                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpFileName));
                reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;
                reqFTP.UseBinary = true;
                reqFTP.Credentials = new NetworkCredential(ftpUserName, ftpPassword);
                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();

                //StreamReader ftpFileListReader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
                Stream ftpStream = response.GetResponseStream();
                int len = 0;
                //List<byte> bytes = new List<byte>();
                int ret = -1;

FileStream outputStream = new FileStream(FolderFormat(localDir, '\\') + fileName, FileMode.Create);

                while ((ret = ftpStream.ReadByte()) != -1)
                {
                    //bytes.Add(Convert.ToByte(ret));
                    len++;
                    outputStream.WriteByte(Convert.ToByte(ret));
                }
                ftpStream.Close();
                response.Close();
                outputStream.Close();
                //byte[] filebuffer = ftpStream.ToArray();
                //long fileLen = ftpFileListReader.
                //byte[] filebuffer = bytes.ToArray();
                //ftpStream.Read(filebuffer, 0, Convert.ToInt32(len));
                return true;
            }
            catch (Exception ex)
            {
                //throw ex.Message();
                return false;
            }
        }
        /// <summary>
        /// 格式化目录
        /// </summary>
        /// <param name="folderPath">要格式化的目录</param>
        /// <param name="fromatChar">格式化的目录分隔符一般为 \ / </param>
        /// <returns>格式化后的目录带目录分隔符</returns>
        public static string FolderFormat(string folderPath, char fromatChar)
        {
            int pos = -1;
            pos = folderPath.LastIndexOf(fromatChar);
            if (pos != folderPath.Length - 1)
            {
                folderPath += fromatChar;
            }
            return folderPath;
        }
        /// <summary>
        /// 下载文件
        /// </summary>
        /// <param name="ftpDir"></param>
        /// <param name="localDir"></param>
        /// <param name="fileName"></param>
        /// <returns></returns>
        /* public bool DownloadFile(string ftpDir, string localDir, string fileName)
         {
             try
             {
                 // 获得文件buffer
                 byte[] fileBuffer = DownloadFile(ftpDir, fileName);
                 if (fileBuffer.Length > 0)
                 {
                     // 如果文件存在，则覆盖，否则创建文件
                     FileStream outputStream = new FileStream(FolderFormat(localDir, '\\') + fileName, FileMode.Create);
                     int bufferSize = 2048;      // 每次读2k
                     int readCount = bufferSize;
                     outputStream.Write(fileBuffer, 0, fileBuffer.Length);

                     //while (readCount <= fileBuffer.Length)
                     //{
                     //    outputStream.Write(fileBuffer, 0, readCount);
                     //    readCount += bufferSize;
                     //}
                     outputStream.Close();
                 }

                 return true;
             }
             catch (Exception ex)
             {
                 //throw ex.Message();
                 return false;
             }
         }*/
    }
}

引用：

var ftp = new FtpFile();
ftp.InitFtpParam(username, pwd);

var ftpPath = string.Format(@"ftp://{0}/{1}{2}", serverid, docname, tt.Rows[0]["PathName"].ToString().Replace("\\", "/"));

bl = ftp.DownloadFile(ftpPath, fileName, LocalPath);