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1、将服务器文件打包下载至本地（压缩包缓存到服务器下载）

（1）文件批量压缩成压缩包并缓存到服务器（公共方法）

using ICSharpCode.SharpZipLib.Checksums;
using ICSharpCode.SharpZipLib.Zip;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Web;/// <summary>
/// 压缩文件(并保存至服务器)
/// </summary>
/// <param name="fileName">要压缩的所有文件（完全路径)</param>
/// <param name="name">压缩后文件路径</param>
/// <param name="Level">压缩级别</param>
public static bool ZipFileMain(List<string> filenames, string name, int Level){ZipOutputStream s = new ZipOutputStream(File.Create(name));Crc32 crc = new Crc32();//压缩级别s.SetLevel(Level); try{foreach (string file in filenames){//打开压缩文件FileStream fs = File.OpenRead(file);byte[] buffer = new byte[fs.Length];fs.Read(buffer, 0, buffer.Length);//建立压缩实体ZipEntry entry = new ZipEntry(System.IO.Path.GetFileName(file));//时间entry.DateTime = DateTime.Now;//空间大小entry.Size = fs.Length;fs.Close();crc.Reset();crc.Update(buffer);entry.Crc = crc.Value;s.PutNextEntry(entry);s.Write(buffer, 0, buffer.Length);}return true;}catch (Exception ex){return false;}finally{s.Finish();s.Close();}return true;
}

（2）实现代码

调用公共方法将文件批量压缩打包成压缩包并下载到服务器，从服务器读取压缩包下载至本地。

List<string> paths=new List<string>(){"1.txt","2.txt"
};
string strSavePath=Server.MapPath("/");
foreach(var path in paths){path=strSavePath+path;
}
string rarName="test.rar";
//调用公共方法
ZipFileMain(paths, strSavePath + rarName, 1);//下载压缩包至本地
string strServerRarPath = strSavePath + rarName;
//文件不存在重新创建
if (!File.Exists(strServerRarPath)){File.Create(strServerRarPath);
}
byte[] bytes = File.ReadAllBytes(strServerRarPath);
//通知浏览器下载文件而不是打开
context.Response.ContentType = "application/octet-stream";
context.Response.AddHeader("Content-Disposition", "attachment;filename="+HttpUtility.UrlEncode(strRarName, System.Text.Encoding.UTF8));
context.Response.BinaryWrite(bytes);
context.Response.Flush();

2、将服务器文件打包下载至本地（压缩包缓存到内存下载）

（1）将文件流压缩返回压缩后的流（公共方法）

/// <summary>
/// 将多个流进行zip压缩，返回压缩后的流.
/// </summary>
/// <param name="streams">key：文件名；value：文件名对应的要压缩的流.</param>
/// <returns>压缩后的流.</returns>
static MemoryStream PackageManyZip(Dictionary<string, Stream> streams){byte[] buffer = new byte[6500];MemoryStream returnStream = new MemoryStream();var zipMs = new MemoryStream();using (ZipOutputStream zipStream = new ZipOutputStream(zipMs)){zipStream.SetLevel(9);foreach (var kv in streams){string fileName = kv.Key;using (var streamInput = kv.Value){zipStream.PutNextEntry(new ZipEntry(fileName));while (true){var readCount = streamInput.Read(buffer, 0, buffer.Length);if (readCount > 0) zipStream.Write(buffer, 0, readCount);else break;}zipStream.Flush();}}zipStream.Finish();zipMs.Position = 0;zipMs.CopyTo(returnStream, 5600);}returnStream.Position = 0;return returnStream;
}

（2）实现代码

将服务器的批量文件以流的形式压缩成一个压缩包流，再将压缩包流下载至本地。

List<string> paths=new List<string>(){"1.txt","2.txt"
};
string strSavePath=Server.MapPath("/");
Dictionary<string, Stream> streamDic = new Dictionary<string, Stream>();
//文件转化成流
foreach(var path in paths){string FileName = path;path=strSavePath+path;//文件不存在if (!File.Exists(path)) continue;//处理文件数据Stream streamWriter = File.Open(path, FileMode.Open);if(streamDic.ContainsKey(FileName)==false){//文件不重名streamDic.Add(FileName, streamWriter);}
}
//压缩
MemoryStream ms = new MemoryStream();
ms = PackageManyZip(streamDic);
byte[] bytes = new byte[(int)ms.Length];
ms.Read(bytes, 0, bytes.Length);
ms.Close();
//通知浏览器下载文件而不是打开
string zipName = DateTime.Today.ToString("yyyy-MM-dd") + ".zip";
Response.ContentType = "application/octet-stream";
Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(zipName, System.Text.Encoding.UTF8));
Response.BinaryWrite(bytes);
Response.Flush();

注：streamDic添加数据时，需要先判断key是否存在，如果key在streamDic中已经存在，在Add相同的key会出现异常导致程序终止运行。