c#实现 ftp ;http;共享方式下载文件 并对比本地文件和服务器文件的更新时间 判断性下载

转载地址：http://www.cnblogs.com/Fengsp/archive/2012/08/06/2625149.htm

//从ftp服务器上下载文件的功能

public void Download(string ftpServerIP, string ftpUserID, string ftpPassword, string fileName, string Destination)

{

FtpWebRequest reqFTP;

try

{

FileStream outputStream = new FileStream(Destination + "\\" + fileName, FileMode.Create);

// 根据uri创建FtpWebRequest对象

reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + fileName));

// 指定执行什么命令

reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;

// 默认为true，连接不会被关闭

reqFTP.UseBinary = true;

// ftp用户名和密码

reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);

FtpWebResponse ftpresponse = (FtpWebResponse)reqFTP.GetResponse();

Stream ftpStream = ftpresponse.GetResponseStream();

long cl = ftpresponse.ContentLength;

int bufferSize = 2048;

int readCount;

byte[] buffer = new byte[bufferSize];

readCount = ftpStream.Read(buffer, 0, bufferSize);

while (readCount > 0)

{

outputStream.Write(buffer, 0, readCount);

readCount = ftpStream.Read(buffer, 0, bufferSize);

}

ftpStream.Close();

outputStream.Close();

ftpresponse.Close();

}

catch (Exception ex)

{

}

}

//从http服务器上下载文件的功能

//为服务器路径server_path

//本地存储路径local_path

public void Download(string server_path, string local_path)

{

HttpWebRequest req;

try

{

string folder = local_path.Substring(0, local_path.LastIndexOf("\\"));

if (!Directory.Exists(folder))

Directory.CreateDirectory(folder);

// 根据uri创建FtpWebRequest对象

req = (HttpWebRequest)HttpWebRequest.Create(new Uri(server_path));

// 指定执行什么命令

req.Method = WebRequestMethods.Http.Get;

HttpWebResponse response = (HttpWebResponse)req.GetResponse();

if (File.Exists(local_path))

{

FileInfo localFile = new FileInfo(local_path);

if (localFile.LastWriteTime > response.LastModified) return;

}

FileStream outputStream = new FileStream(local_path, FileMode.Create);

Stream stream = response.GetResponseStream();

long cl = response.ContentLength;

int bufferSize = 2048;

int readCount;

byte[] buffer = new byte[bufferSize];

readCount = stream.Read(buffer, 0, bufferSize);

while (readCount > 0)

{

outputStream.Write(buffer, 0, readCount);

readCount = stream.Read(buffer, 0, bufferSize);

}

stream.Close();

outputStream.Close();

response.Close();

}

catch (Exception ex)

{

string s = ex.Message;

}

}

//从共享文件夹下载

public void Download(string server_path, string local_path, int i)

{

try

{

server_path = "\\" + server_path;

string folder = local_path.Substring(0, local_path.LastIndexOf("\\"));

if (!Directory.Exists(folder))

Directory.CreateDirectory(folder);

if (!File.Exists(server_path)) return;

//服务器文件信息

FileInfo serverInfo = new FileInfo(server_path);

DateTime serverTime = serverInfo.LastWriteTime;

if (File.Exists(local_path))

{

FileInfo localinfo = new FileInfo(local_path);

DateTime localTime = localinfo.LastWriteTime;

if (localTime >= serverTime)

return;

}

serverInfo.CopyTo(local_path, true);

return;

}

catch (Exception ex)

{

string s = ex.Message;

}

}