如何直接处理FTP服务器上的压缩文件?
我最近要写一个供有相关权限的管理人员查询大额资金明细的程序，界面如下：所需的数据文件是放在报表服务器上，每天一个压缩文件，该压缩文件中除了所需的储蓄流水账文件外，还有很多其他的文件。如果先把该压缩文件从报表服务器下载到应用服务器上，再进行解压缩处理的话，一是多下载了该压缩文件中我们不需要的其他文件，二是还必须在应用服务器上建立以SessionID等方法标识的临时文件，以免其他用户也在进行查询时文件名冲突，三是使用完毕后还必须删除该临时文件。
我的处理方法是如下：
using (ZipInputStream zs = Zip.GetZipInputStream((new FtpClient(Pub.Ftp1Uri, Pub.Ftp1User, Pub.Ftp1Pswd)).
GetDownloadStream(Path.Combine(Pub.Ftp1EPath, zipFileName)), binFileName, out size))
{
if (size % Pub.P_R2 != 0) throw new ApplicationException("文件长度错: " + binFileName);
byte [] bs = new byte;
long recs = size / Pub.P_R2;
for (long rec = 0; rec < recs; rec++)
{
Zip.ReadStream(zs, bs);
...
}
首先，用 FtpClient.GetDownloadStream() 方法得到一个对应于FTP服务器上文件的Stream，然后把这个Stream传给Zip.GetZipInputStream()方法，得到一个ZipInputStream，然后使用Zip.ReadStream()方法一行一行读取储蓄流水账文件到byte[]中去，这样就取得了我们所需的数据，就象储蓄流水账文件就存放在本地硬盘上一样，避免了下载文件和解压文件。具体代码如下：
1using System;
2using System.IO;
3using System.Net;
4
5namespace Skyiv.Util
6{
7sealed class FtpClient
8{
9 Uri uri;
10 string userName;
11 string password;
12
13 public FtpClient(string uri, string userName, string password)
14 {
15 this.uri = new Uri(uri);
16 this.userName = userName;
17 this.password = password;
18 }
19
20 public Stream GetDownloadStream(string sourceFile)
21 {
22 Uri downloadUri = new Uri(uri, sourceFile);
23 if (downloadUri.Scheme != Uri.UriSchemeFtp) throw new ArgumentException("URI is not an FTP site");
24 FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(downloadUri);
25 ftpRequest.Credentials = new NetworkCredential(userName, password);
26 ftpRequest.Method = WebRequestMethods.Ftp.DownloadFile;
27 return ((FtpWebResponse)ftpRequest.GetResponse()).GetResponseStream();
28 }
29
30 /**//*public */void Download(string sourceFile, string destinationFile)
31 {
32 using (Stream reader = GetDownloadStream(sourceFile))
33 {
34 using (BinaryWriter bw = new BinaryWriter(new FileStream(destinationFile, FileMode.Create)))
35 {
36 for (;;)
37 {
38 int c = reader.ReadByte();
39 if (c == -1) break;
40 bw.Write((byte)c);
41 }
42 }
43 }
44 }
45}
46}
47
1using System;
2using System.IO;
3using ICSharpCode.SharpZipLib.Zip;
4
5namespace Skyiv.Util
6{
7static class Zip
8{
9 public static void ReadStream(Stream inStream, byte [] bs)
10 {
11 int offset = 0;
12 int count = bs.Length;
13 do
14 {
15 int size = inStream.Read(bs, offset, count);
16 if (size0);
20 if (count != 0) throw new ApplicationException("Zip.ReadStream(): 读输入流错");
21 }
22
23 public static ZipInputStream GetZipInputStream(string zipFileName, string fileName, out long fileLength)
24 {
25 return GetZipInputStream(File.OpenRead(zipFileName), fileName, out fileLength);
26 }
27
28 public static ZipInputStream GetZipInputStream(Stream zipStream, string fileName, out long fileLength)
29 {
30 ZipInputStream zs = new ZipInputStream(zipStream);
31 ZipEntry theEntry;
32 while ((theEntry = zs.GetNextEntry()) != null)
33 {
34 if (Path.GetFileName(theEntry.Name) != fileName) continue;
35 fileLength = theEntry.Size;
36 return zs;
37 }
38 fileLength = -1;
39 return null;
40 }
41
42 /**//*public */static void UnzipFile(string zipFile, string baseStr, params string [] fileList)
43 {
44 UnzipFile(File.OpenRead(zipFile), baseStr, fileList);
45 }
46
47 /**//*public */static void UnzipFile(Stream zipStream, string baseStr, params string [] fileList)
48 {
49 using (ZipInputStream zs = new ZipInputStream(zipStream))
50 {
51 ZipEntry theEntry;
52 byte[] data = new byte;
53 while ((theEntry = zs.GetNextEntry()) != null) {
54 if (Array.IndexOf(fileList, Path.GetFileName(theEntry.Name)) < 0) continue;
55 using (FileStream sw = new FileStream(baseStr+Path.GetFileName(theEntry.Name), FileMode.Create))
56 {
57 while (true) {
58 int size = zs.Read(data, 0, data.Length);
59 if (size
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