C#本地文件下载以及FTP文件服务下载（以Pdf文件为例）
一、C#实现本地文件下载
1、文件下载的路径 文件名称 以及文件下载之后要放的位置 这三个变量是必须要的
2、定义以下四个对象：
FileWebRequest ftpWebRequest = null; FileWebResponse ftpWebResponse = null; Stream ftpResponseStream = null; FileStream outputStream = null;
3、创建文件下载存放位置的路径（不需要手动创建，如果路径存在就创建 不存在就不创建）
Directory.CreateDirectory(LocalFolder);//创建文件夹名称
* 这里提一点 Path.Combine（）这个就是文件路径拼接的函数，会自动判断，在需要的文件加 \\
比如 string filePath= Path.Combine（“D:”，“test”,"download"）; // filePath="D:\\test\download";
4、 然后执行以下代码 即可完成文件下载
ftpWebRequest = (FileWebRequest)FileWebRequest.Create(new Uri(uri));
ftpWebRequest.Method = WebRequestMethods.Ftp.DownloadFile;
ftpWebResponse = (FileWebResponse)ftpWebRequest.GetResponse();
ftpResponseStream = ftpWebResponse.GetResponseStream();
long contentLength = ftpWebResponse.ContentLength;
int bufferSize = 2048;
byte[] buffer = new byte[bufferSize];
int readCount;
readCount = ftpResponseStream.Read(buffer, 0, bufferSize);
while (readCount > 0)
{
outputStream.Write(buffer, 0, readCount);
readCount = ftpResponseStream.Read(buffer, 0, bufferSize);
}
5、代码写完之后要思考，下载文件的时候如何出现异常 这时在整个代码加个 Try{} catch{}
具体代码如下：
public static void Main(string[] args)
{
TestFile tf = new TestFile();
tf.fileDownload("D:/testFile/", "下载ftp文件.txt", "C:/Users/17/Desktop/文件", "下载ftp文件.txt", DateTime.Now.ToShortDateString());
}
/// <summary>
/// 下载文件
/// </summary>
/// <param name="localPath">本地文件地址(没有文件名)</param>
/// <param name="localFileName">本地文件名</param>
/// <param name="ftpPath">下载的ftp的路径</param>
/// <param name="ftpFileName">下载的ftp的文件名</param>
public bool fileDownload(string localPath, string localFileName, string ftpPath, string ftpFileName, string date)
{
bool success = false;
//FtpWebResponse ftpWebResponse = null;
FileWebRequest ftpWebRequest = null;
FileWebResponse ftpWebResponse = null;
Stream ftpResponseStream = null;
FileStream outputStream = null;
try
{
//string date = DateTime.Now.ToShortDateString().ToString();//获取系统时间
string date1 = date.Replace("/", "");//winods 中文件命名不能有 / 去掉指定字符串 /
//localPath = localPath + date1 + "/";//拼接路径
localPath=Path.Combine(localPath,date1)
Directory.CreateDirectory(localPath);//创建文件夹名称
outputStream = new FileStream(localPath + localFileName, FileMode.Create);//创建文件
string uri = ftpRootURL + ftpPath + "/" + ftpFileName;//拼接目标文件路径
string uri= Path.Combine(ftpRootURL,ftpPath,ftpFileName);
ftpWebRequest = (FileWebRequest)FileWebRequest.Create(new Uri(uri));
//ftpWebRequest1.UseBinary = true;
ftpWebRequest.Method = WebRequestMethods.Ftp.DownloadFile;
ftpWebResponse = (FileWebResponse)ftpWebRequest.GetResponse();
ftpResponseStream = ftpWebResponse.GetResponseStream();
long contentLength = ftpWebResponse.ContentLength;
int bufferSize = 2048;
byte[] buffer = new byte[bufferSize];
int readCount;
readCount = ftpResponseStream.Read(buffer, 0, bufferSize);
while (readCount > 0)
{
outputStream.Write(buffer, 0, readCount);
readCount = ftpResponseStream.Read(buffer, 0, bufferSize);
}
success = true;
}
catch (Exception e)
{
DirectoryInfo folder = new DirectoryInfo(localPath);
StreamWriter log = new StreamWriter(localPath + "/" + DateTime.Now.ToShortDateString().ToString().Replace("/", "") + ".txt", true);
log.WriteLine("发生异常时间:" + System.DateTime.Now.ToShortTimeString().ToString());
log.WriteLine("发生异常信息:" + e.Message);
log.WriteLine("发送异常对象:" + e.Source);
log.WriteLine("调用堆栈:" + e.StackTrace.Trim());
log.WriteLine("触动方法:" + e.TargetSite);
log.WriteLine(" " + e.HResult);
log.WriteLine("数据对象" + e.Data);
log.WriteLine("____________________________________________________________");
log.WriteLine();
log.Close();
success = false;
}
finally
{
if (outputStream != null)
{
outputStream.Close();
}
if (ftpResponseStream != null)
{
ftpResponseStream.Close();
}
if (ftpWebResponse != null)
{
ftpWebResponse.Close();
}
}
return success;
}
二、 FTP 服务文件下载
这个功能其实和本地文件下载一样，只需要加几点即可
1、FTP服务的地址；
具体代码如下
private string ftpIP = "**********";
2、FTP文件服务的登录账号以及密码
具体代码如下
private string ftpName = "*********"; private string ftpPassword = "******"; private string ftpRootURL = string.Empty; FtpWebRequest reqFTP;
3、获取FTP服务上的文件名称、FTP文件服务需要下载之后存放的路径以及下载功能的实现
FtpWebRequest ftpWebRequest = null;
FtpWebResponse ftpWebResponse = null;
Stream ftpResponseStream = null;
FileStream outputStream = null;
try
{
localFilePath = Path.Combine(localFilePath, ftpFileNameTime);
Directory.CreateDirectory(localFilePath);//创建文件夹名称
outputStream = new FileStream(Path.Combine(localFilePath, fileName), FileMode.Create);
string uri = Path.Combine(ftpRootURL, ftpIP, fileName);
ftpWebRequest = (FtpWebRequest)FileWebRequest.Create(new Uri(uri));
ftpWebRequest.Credentials = new NetworkCredential(ftpName, ftpPassword);//登录ftp
ftpWebRequest.UseBinary = true;
ftpWebRequest.Method = WebRequestMethods.Ftp.DownloadFile;
ftpWebResponse = (FtpWebResponse)ftpWebRequest.GetResponse();
ftpResponseStream = ftpWebResponse.GetResponseStream();
long contentLength = ftpWebResponse.ContentLength;
int bufferSize = 2048;
byte[] buffer = new byte[bufferSize];
int readCount;
readCount = ftpResponseStream.Read(buffer, 0, bufferSize);
while (readCount > 0)
{
outputStream.Write(buffer, 0, readCount);
readCount = ftpResponseStream.Read(buffer, 0, bufferSize);
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message）
/*MessageBox.Show(ex.Message + "是否下载日志文件", "发送错误！", MessageBoxButtons.OKCancel);
//点击确定 就执行下载日志文件，不然就不执行
if (dr == DialogResult.OK)
{
WriteLog log = new WriteLog();
log.Write_log(ex.Message);
}*/
}
finally
{
if (outputStream != null)
{
outputStream.Close();
}
if (ftpResponseStream != null)
{
ftpResponseStream.Close();
}
if (ftpWebResponse != null)
{
ftpWebResponse.Close();
}
}
5、具体代码如下：
namespace FtpDownLoad
{
public class ftpFileDownload
{
private string ftpIP = "*************";
private string ftpName = "2*******";
private string ftpPassword = "*********";
private string ftpRootURL = string.Empty;
FtpWebRequest reqFTP;
public static void Main(string[] args)
{
ftpFileDownload ftpDown = new ftpFileDownload();
ftpDown.GetFileList("D:\testFile","37.pdt","20190703");
}
/// <summary>
/// 文件下载
/// </summary>
/// <param name="localFilePath">下载路径</param>
/// <param name="fileName">下载的名称</param>
/// <param name="ftpFilePath">FTP路径</param>
/// <param name="ftpFileNameTime">FTP文件的修改时间</param>
public void FtpDownLoadFile(string localFilePath, string fileName, string ftpFileNameTime)
{
FtpWebRequest ftpWebRequest = null;
FtpWebResponse ftpWebResponse = null;
Stream ftpResponseStream = null;
FileStream outputStream = null;
try
{
localFilePath = Path.Combine(localFilePath, ftpFileNameTime);
Directory.CreateDirectory(localFilePath);//创建文件夹名称
outputStream = new FileStream(Path.Combine(localFilePath, fileName), FileMode.Create);
string uri = Path.Combine(ftpRootURL, ftpIP, fileName);
ftpWebRequest = (FtpWebRequest)FileWebRequest.Create(new Uri(uri));
ftpWebRequest.Credentials = new NetworkCredential(ftpName, ftpPassword);//登录ftp
ftpWebRequest.UseBinary = true;
ftpWebRequest.Method = WebRequestMethods.Ftp.DownloadFile;
ftpWebResponse = (FtpWebResponse)ftpWebRequest.GetResponse();
ftpResponseStream = ftpWebResponse.GetResponseStream();
long contentLength = ftpWebResponse.ContentLength;
int bufferSize = 2048;
byte[] buffer = new byte[bufferSize];
int readCount;
readCount = ftpResponseStream.Read(buffer, 0, bufferSize);
while (readCount > 0)
{
outputStream.Write(buffer, 0, readCount);
readCount = ftpResponseStream.Read(buffer, 0, bufferSize);
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
/* DialogResult dr = MessageBox.Show(ex.Message + "是否下载日志文件", "发送错误！", MessageBoxButtons.OKCancel);
//点击确定 就执行下载日志文件，不然就不执行
if (dr == DialogResult.OK)
{
WriteLog log = new WriteLog();
log.Write_log(ex.Message);
}*/
}
finally
{
if (outputStream != null)
{
outputStream.Close();
}
if (ftpResponseStream != null)
{
ftpResponseStream.Close();
}
if (ftpWebResponse != null)
{
ftpWebResponse.Close();
}
}
}
如有疑问 可以往773408602@qq.com发邮件，我会第一时间给你解答的
