一、前言
网上有许多的多线程 断点续传 操作,但总是写的很云里雾里,或者写的比较坑长。由于这几个月要负责公司的在线升级项目,所以正好顺便写了一下
代码如下:
using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
namespace TestCenter
{
class Program
{
static void Main( string [] args)
{
string LocalSavePath = @"E:\Test\TestFile\Local\1.msi" ; //本地目标文件路径
FileInfo SeverFilePath = new FileInfo( @"E:\Test\TestFile\Server\1.msi" ); //服务器待文件路径
long FileLength = SeverFilePath.Length; //待下载文件大小
Console.WriteLine( "Start Configuration" );
int PackCount = 0; //初始化数据包个数
long PackSize = 1024000; //数据包大小
if (FileLength % PackSize > 0)
{
PackCount = ( int )(FileLength / PackSize) + 1;
}
else
{
PackCount = ( int )(FileLength / PackSize);
}
Console.WriteLine( "Start Recieve" );
var tasks = new Task[PackCount]; //多线程任务
for ( int index = 0; index < PackCount; index++)
{
int Threadindex = index; //这步很关键,在Task()里的绝对不能直接使用index
var task = new Task(() =>
{
string tempfilepath = @"E:\Test\TestFile\Temp\" + "QS_ " + Threadindex + " _" + PackCount; //临时文件路径
using ( FileStream tempstream = new FileStream(tempfilepath, FileMode.Create, FileAccess.Write, FileShare.Write))
{
int length = ( int )Math.Min(PackSize, FileLength - Threadindex * PackSize);
var bytes = GetFile(Threadindex*PackCount, length);
tempstream.Write(bytes, 0, length);
tempstream.Flush();
tempstream.Close();
tempstream.Dispose();
}
});
tasks[Threadindex] = task;
task.Start();
}
Task.WaitAll(tasks); //等待所有线程完成
Console.WriteLine( "Recieve End" );
//检测有哪些数据包未下载
Console.WriteLine( "Start Compare" );
DirectoryInfo TempDir = new DirectoryInfo( @"E:\Test\TestFile\temp" ); //临时文件夹路径
List< string > Comparefiles = new List< string >();
for ( int i = 0; i < PackCount; i++)
{
bool hasfile = false ;
foreach (FileInfo Tempfile in TempDir.GetFiles())
{
if (Tempfile.Name.Split( '_' )[1] == i.ToString())
{
hasfile = true ;
break ;
}
}
if (hasfile == false )
{
Comparefiles.Add(i.ToString());
}
}
//最后补上这些缺失的文件
if (Comparefiles.Count > 0)
{
foreach ( string com_index in Comparefiles)
{
string tempfilepath = @"E:\Test\TestFile\Temp\" + "QS_ " + com_index+ " _" + PackCount;
using (FileStream Compstream = new FileStream(tempfilepath, FileMode.Create, FileAccess.Write, FileShare.Write))
{
int length = ( int )Math.Min(PackSize, FileLength - Convert.ToInt32(com_index) * PackSize);
var bytes = GetFile(Convert.ToInt32(com_index)*PackCount, length);
Compstream.Write(bytes, 0, length);
Compstream.Flush();
Compstream.Close();
Compstream.Dispose();
}
}
}
Console.WriteLine( "Compare End" );
//准备将临时文件融合并写到1.msi中
Console.WriteLine( "Start Write" );
using (FileStream writestream = new FileStream(LocalSavePath, FileMode.Create, FileAccess.Write, FileShare.Write))
{
foreach (FileInfo Tempfile in TempDir.GetFiles())
{
using (FileStream readTempStream = new FileStream(Tempfile.FullName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
{
long onefileLength = Tempfile.Length;
byte [] buffer = new byte [Convert.ToInt32(onefileLength)];
readTempStream.Read(buffer, 0, Convert.ToInt32(onefileLength));
writestream.Write(buffer, 0, Convert.ToInt32(onefileLength));
}
}
writestream.Flush();
writestream.Close();
writestream.Dispose();
}
Console.WriteLine( "Write End" );
//删除临时文件
Console.WriteLine( "Start Delete Temp Files" );
foreach (FileInfo Tempfile in TempDir.GetFiles())
{
Tempfile.Delete();
}
Console.WriteLine( "Delete Success" );
Console.ReadKey();
}
//这个方法可以放到Remoting或者WCF服务中去,然后本地调用该方法即可实现多线程断点续传
public static byte [] GetFile( int start, int length)
{
string SeverFilePath = @"E:\Test\TestFile\Server\1.msi" ;
using (FileStream ServerStream = new FileStream(SeverFilePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite, 1024*80, true ))
{
byte [] buffer = new byte [length];
ServerStream.Position = start;
//ServerStream.Seek(start, SeekOrigin.Begin);
ServerStream.Read(buffer, 0, length);
return buffer;
}
}
}
}
二、讨论
1)需要注意的是第44行,不能直接使用index变量在Task()里进行操作,而是要将它赋给Threadindex,让Threadindex在Task()里,不然会直接报错,为什么呢? 查看链接
2)70至108行代码可以在外面再套一层while循环,循环检测临时文件是否下完整了,然后再定义一个检测最大上限,超过这个上限就放弃本次更新,当用户的网络恢复正常后下次再做更新操作。所以说放临时文件的文件夹最好要包含版本信息,不会把2.0.0的临时文件和1.0.0的临时文件搞混。
3) FileStream.Position 与 FileStream.Seek(long offset, SeekOrigin seekorigin) 的作用都是获取流的指针位置,当文件路径使用绝对路径时使用Position;相对路径时使用Seek方法, 查看链接
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:http://HdhCmsTestcnblogs测试数据/lovecsharp094/p/5727141.html
dy("nrwz");
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