【Unity开发】UNITY实现断点续传

using UnityEngine;

using System.Collections;
using System.IO;
using System.Threading;
using System.Net;

public class wishDownload : MonoBehaviour
{
/// <summary>
/// URL下载路径
/// </summary>
private string wish_DownLoadURL;
/// <summary>
/// 临时存放地址
/// </summary>
private string wish_Temporarypath;
/// <summary>
/// 完整应用存放地址
/// </summary>
private string wish_Installpath;
/// <summary>
/// 存储文件名
/// </summary>
private string wish_FileName;
/// <summary>
/// 临时存放后缀。要区别于正式后缀名，否则下载中断后无法继续下载。
/// </summary>
private string wish_Temporarysuffix;
/// <summary>
/// 正式后缀名，例.apk
/// </summary>
private string wish_Filesuffix;
private Thread wish_Thread;

string strUrl = "http://dlsw.baidu.com/sw-search-sp/soft/ca/13442/Thunder_dl_7.9.42.5050.1449557123.exe";
void Start()
{
//设置并发数，默认为2，容易异常
System.Net.ServicePointManager.DefaultConnectionLimit = 512;
DownloadStart(strUrl, "poda", Application.dataPath, Application.dataPath, ".temp", ".exe");
}

public void DownloadStart(string URL, string FileName, string

Temporarypath, string Installpath, string Temporarysuffix, string

Filesuffix)
{
wish_DownLoadURL = URL;
wish_FileName = FileName;
wish_Temporarypath = Temporarypath;
wish_Installpath = Installpath;
wish_Temporarysuffix = Temporarysuffix;
wish_Filesuffix = Filesuffix;

CheckFolder(wish_Temporarypath);
CheckFolder(wish_Installpath);

CheckFile(wish_FileName, URL);
}
/// <summary>
/// 判断路径是否存在
/// </summary>
/// <param name="path"></param>
void CheckFolder(string path)
{
if (Directory.Exists(path) == false)
{
Directory.CreateDirectory(path);
}
}
/// <summary>
/// 判断完整文件是否存在
/// </summary>
/// <param name="fileName"></param>
/// <param name="url"></param>
public void CheckFile(string fileName, string url)
{
if (File.Exists(wish_Installpath + "/" + fileName + wish_Filesuffix))
{
// 文件存在，不用下载
}
else
{
DownFile(fileName, url);
}
}

void DownFile(string fileName, string url)
{
DownThread DW = new DownThread(fileName + wish_Temporarysuffix,

wish_Temporarypath + "/" + fileName + wish_Temporarysuffix, url,

wish_Filesuffix, wish_Temporarysuffix, wish_Temporarypath,

wish_Installpath);

wish_Thread = new Thread(new ThreadStart(DW.Down));

wish_Thread.Start();
}

class DownThread
{
string name;
string url;
string fileName;
long DownloadByte;
string Filesuffix;
string Temporarysuffix;
string Temporarypath;
string Installpath;

public DownThread(string fileName, string name, string url, string

Filesuffix, string Temporarysuffix, string Temporarypath, string

Installpath)
{
this.fileName = fileName;
this.name = name; //临时存放名
this.url = url;
this.Filesuffix = Filesuffix;
this.Temporarysuffix = Temporarysuffix;
this.Temporarypath = Temporarypath;
this.Installpath = Installpath;
}

public void Down()
{
DownloadByte = 0;
long lStartPos = 0;
FileStream fs;

if (File.Exists(name))
{
fs = File.OpenWrite(name);
lStartPos = fs.Length; //取得文件长度，继续下载
fs.Seek(lStartPos, SeekOrigin.Current);
}
else
{
fs = new FileStream(name, FileMode.Create);
lStartPos = 0;
}

try
{
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
if (lStartPos > 0)
{
request.AddRange((int)lStartPos);
}
Stream ns = request.GetResponse().GetResponseStream();
byte[] nbytes = new byte[8192];
int nReadSize = 0;
nReadSize = ns.Read(nbytes, 0, 8192);
while (nReadSize > 0)
{
fs.Write(nbytes, 0, nReadSize);

nReadSize = ns.Read(nbytes, 0, 8192);
}

string changeName;
changeName = name.Substring(0, name.LastIndexOf("."));
changeName += Filesuffix;
changeName = changeName.Replace(Temporarypath, Installpath);

fs.Close();

ns.Close();

if (File.Exists(name))
{
Debug.Log(name);
Debug.Log(changeName);

try
{
File.Move(name, changeName);
}
catch (System.Exception e)
{
Debug.Log(e.ToString());
throw;
}
}
}
catch
{
fs.Close();
}
}
}
}