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

0755mx

　　近段时间在研究这个下载 在网上找了一些列子看了看 决定把这几种下载综合起来发一个……



//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;  
}  
}