C# 将服务器文件批量压缩打包下载至本地两种方法（压缩包缓存到服务器下载、压缩包缓存到内存下载）

怼烎@ 2023-10-05 08:42 25阅读 0赞

#### 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。