[C#] Detailed explanation of examples of FtpHelper implementing read and write operations on server files

using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Net;
 using System.IO;
 using System.Threading;
using System.Configuration;
 
 namespace FtpSyn
 {
   public class FtpHelper
   {
     //基本设置 ftp://400:ZOina2017@192.168.10.17/400backup
     static private string path = @"ftp://" + ConfigurationManager.AppSettings["FtpServerIP"].ToString() + "/";  //目标路径
     static private string ftpip = ConfigurationManager.AppSettings["FtpServerIP"].ToString();  //ftp IP地址
     static private string username = ConfigurationManager.AppSettings["FtpUserName"].ToString();  //ftp用户名
     static private string password = ConfigurationManager.AppSettings["FtpPassWord"].ToString();  //ftp密码
    
     //获取ftp上面的文件和文件夹
     public static string[] GetFileList(string dir)
     {
       string[] downloadFiles;
       StringBuilder result = new StringBuilder();
       FtpWebRequest request;
       try
       {
         request = (FtpWebRequest)FtpWebRequest.Create(new Uri(path + dir));
         request.UseBinary = true;
         request.Credentials = new NetworkCredential(username, password);//设置用户名和密码
         request.Method = WebRequestMethods.Ftp.ListDirectory;
         request.UseBinary = true;
         request.UsePassive = false; //选择主动还是被动模式 , 这句要加上的。
         request.KeepAlive = false;//一定要设置此属性，否则一次性下载多个文件的时候，会出现异常。
         WebResponse response = request.GetResponse();
         StreamReader reader = new StreamReader(response.GetResponseStream());
 
         string line = reader.ReadLine();
         while (line != null)
         {
           result.Append(line);
           result.Append("\n");
           line = reader.ReadLine();
         }
 
         result.Remove(result.ToString().LastIndexOf('\n'), 1);
         reader.Close();
         response.Close();
         return result.ToString().Split('\n');
       }
       catch (Exception ex)
       {
         LogHelper.writeErrorLog("获取ftp上面的文件和文件夹：" + ex.Message);
         downloadFiles = null;
         return downloadFiles;
       }
     }
 
     /// <summary>
     /// 从ftp服务器上获取文件并将内容全部转换成string返回
     /// </summary>
     /// <param name="fileName"></param>
     /// <param name="dir"></param>
     /// <returns></returns>
     public static string GetFileStr(string fileName, string dir)
     {
       FtpWebRequest reqFTP;
       try
       {
         reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(path + dir + "/" + fileName));
         reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;
         reqFTP.UseBinary = true;
         reqFTP.Credentials = new NetworkCredential(username, password);
         reqFTP.UsePassive = false; //选择主动还是被动模式 , 这句要加上的。
         reqFTP.KeepAlive = false;//一定要设置此属性，否则一次性下载多个文件的时候，会出现异常。
         FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
         Stream ftpStream = response.GetResponseStream();
         StreamReader reader = new StreamReader(ftpStream);
         string fileStr = reader.ReadToEnd();
 
         reader.Close();
         ftpStream.Close();
         response.Close();
         return fileStr;
       }
       catch (Exception ex)
       {
         LogHelper.writeErrorLog("获取ftp文件并读取内容失败：" + ex.Message);
         return null;
       }
     } 
 
     /// <summary>
     /// 获取文件大小
     /// </summary>
     /// <param name="file">ip服务器下的相对路径</param>
     /// <returns>文件大小</returns>
     public static int GetFileSize(string file)
     {
       StringBuilder result = new StringBuilder();
       FtpWebRequest request;
       try
       {
         request = (FtpWebRequest)FtpWebRequest.Create(new Uri(path + file));
         request.UseBinary = true;
         request.Credentials = new NetworkCredential(username, password);//设置用户名和密码
         request.Method = WebRequestMethods.Ftp.GetFileSize;
 
         int dataLength = (int)request.GetResponse().ContentLength;
 
         return dataLength;
       }
       catch (Exception ex)
       {
         Console.WriteLine("获取文件大小出错：" + ex.Message);
         return -1;
       }
     }
 
     /// <summary>
     /// 文件上传
     /// </summary>
     /// <param name="filePath">原路径（绝对路径）包括文件名</param>
     /// <param name="objPath">目标文件夹：服务器下的相对路径 不填为根目录</param>
     public static void FileUpLoad(string filePath,string objPath="")
     {
       try
       {
         string url = path;
         if(objPath!="")
           url += objPath + "/";
         try
         {
 
           FtpWebRequest reqFTP = null;
           //待上传的文件 （全路径）
           try
           {
             FileInfo fileInfo = new FileInfo(filePath);
             using (FileStream fs = fileInfo.OpenRead())
             {
               long length = fs.Length;
               reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(url + fileInfo.Name));
 
               //设置连接到FTP的帐号密码
               reqFTP.Credentials = new NetworkCredential(username, password);
               //设置请求完成后是否保持连接
               reqFTP.KeepAlive = false;
               //指定执行命令
               reqFTP.Method = WebRequestMethods.Ftp.UploadFile;
               //指定数据传输类型
               reqFTP.UseBinary = true;
 
               using (Stream stream = reqFTP.GetRequestStream())
               {
                 //设置缓冲大小
                 int BufferLength = 5120;
                 byte[] b = new byte[BufferLength];
                 int i;
                 while ((i = fs.Read(b, 0, BufferLength)) > 0)
                 {
                   stream.Write(b, 0, i);
                 }
                 Console.WriteLine("上传文件成功");
               }
             }
           }
           catch (Exception ex)
           {
             Console.WriteLine("上传文件失败错误为" + ex.Message);
           }
           finally
           {
 
           }
         }
         catch (Exception ex)
         {
           Console.WriteLine("上传文件失败错误为" + ex.Message);
         }
         finally
         {
 
         }
       }
       catch (Exception ex)
       {
         Console.WriteLine("上传文件失败错误为" + ex.Message);
       }
     }
     
     /// <summary>
     /// 删除文件
     /// </summary>
     /// <param name="fileName">服务器下的相对路径 包括文件名</param>
     public static void DeleteFileName(string fileName)
     {
       try
       {
         FileInfo fileInf = new FileInfo(ftpip +""+ fileName);
         string uri = path + fileName;
         FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
         // 指定数据传输类型
         reqFTP.UseBinary = true;
         // ftp用户名和密码
         reqFTP.Credentials = new NetworkCredential(username, password);
         // 默认为true，连接不会被关闭
         // 在一个命令之后被执行
         reqFTP.KeepAlive = false;
         // 指定执行什么命令
         reqFTP.Method = WebRequestMethods.Ftp.DeleteFile;
         FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
         response.Close();
       }
       catch (Exception ex)
       {
         Console.WriteLine("删除文件出错：" + ex.Message);
       }
     }
     
     /// <summary>
     /// 新建目录 上一级必须先存在
     /// </summary>
     /// <param name="dirName">服务器下的相对路径</param>
     public static void MakeDir(string dirName)
     {
       try
       {
         string uri = path + dirName;
         FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
         // 指定数据传输类型
         reqFTP.UseBinary = true;
         // ftp用户名和密码
         reqFTP.Credentials = new NetworkCredential(username, password);
         reqFTP.Method = WebRequestMethods.Ftp.MakeDirectory;
         FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
         response.Close();
       }
       catch (Exception ex)
       {
         Console.WriteLine("创建目录出错：" + ex.Message);
       }
     }
     
     /// <summary>
     /// 删除目录 上一级必须先存在
     /// </summary>
     /// <param name="dirName">服务器下的相对路径</param>
     public static void DelDir(string dirName)
     {
       try
       {
         string uri = path + dirName;
         FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
         // ftp用户名和密码
         reqFTP.Credentials = new NetworkCredential(username, password);
         reqFTP.Method = WebRequestMethods.Ftp.RemoveDirectory;
         FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
         response.Close();
       }
       catch (Exception ex)
       {
         Console.WriteLine("删除目录出错：" + ex.Message);
       }
     }
 
     /// <summary>
     /// 从ftp服务器上获得文件夹列表
     /// </summary>
     /// <param name="RequedstPath">服务器下的相对路径</param>
     /// <returns></returns>
     public static List<string> GetDirctory(string RequedstPath)
     {
       List<string> strs = new List<string>();
       try
       {
         string uri = path + RequedstPath;  //目标路径 path为服务器地址
         FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
         // ftp用户名和密码
         reqFTP.Credentials = new NetworkCredential(username, password);
         reqFTP.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
         WebResponse response = reqFTP.GetResponse();
         StreamReader reader = new StreamReader(response.GetResponseStream());//中文文件名
 
         string line = reader.ReadLine();
         while (line != null)
         {
           if (line.Contains("<DIR>"))
           {
             string msg = line.Substring(line.LastIndexOf("<DIR>")+5).Trim();
             strs.Add(msg);
           }
           line = reader.ReadLine();
         }
         reader.Close();
         response.Close();
         return strs;
       }
       catch (Exception ex)
       {
         Console.WriteLine("获取目录出错：" + ex.Message);
       }
       return strs;
     }
 
     /// <summary>
     /// 从ftp服务器上获得文件列表
     /// </summary>
     /// <param name="RequedstPath">服务器下的相对路径</param>
     /// <returns></returns>
     public static List<string> GetFile(string RequedstPath)
     {
       List<string> strs = new List<string>();
       try
       {
         string uri = path + RequedstPath;  //目标路径 path为服务器地址
         FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
         // ftp用户名和密码
         reqFTP.Credentials = new NetworkCredential(username, password);
         reqFTP.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
         WebResponse response = reqFTP.GetResponse();
         StreamReader reader = new StreamReader(response.GetResponseStream());//中文文件名
 
         string line = reader.ReadLine();
         while (line != null)
         {
           if (!line.Contains("<DIR>"))
           {
             string msg = line.Substring(39).Trim();
             strs.Add(msg);
           }
           line = reader.ReadLine();
         }
         reader.Close();
         response.Close();
         return strs;
       }
       catch (Exception ex)
       {
         Console.WriteLine("获取文件出错：" + ex.Message);
       }
       return strs;
     }
   
   }
 }