关于JAVA断点续传

sblove 2007-11-22 12:41:45

各位牛人，小弟最近要开发个B/S结构的系统，，需要上传文件可以实现断点续传，有那位牛人能帮帮小弟，最好有个实例给我参考，，万分感激！
我的邮箱：xllly@126.com
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idm2008 2008-11-15

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好像不行啊。谁能说的更具体点吗？

thirtysix1207 2007-11-27

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mark

liu_zhaoqf 2007-11-27

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mark

piaopiao11 2007-11-27

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下载能实现是由web服务器支持才可以实现的
上传。。。不好搞

piaopiao11 2007-11-27

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上传能搞吗？下载当然是可以的

guaxixi627 2007-11-27

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mark

sureyor 2007-11-27

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B/S断点续传? 除了用OCX或者ActiveX之外还能有别的招吗? hoho...

zhb_821012 2007-11-26

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恩
上传跟下载道理一样的吧
友情up

haizhen448 2007-11-26

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tomsmish 2007-11-26

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有分没有.

胡矣 2007-11-26

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MARK 好东西

I_am_Z 2007-11-24

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学习一下。

hupeng45 2007-11-24

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很好的东西

lavijar 2007-11-22

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好东东，收藏。谢谢分享。

楼主要上传文件可以实现断点续传，这个应该是下载的。

wunan320 2007-11-22

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先保存下来慢慢看

iskyshop 2007-11-22

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/*

**SiteInfoBean.java

*/

package NetFox;

public class SiteInfoBean {

private String sSiteURL; //Site's URL

private String sFilePath; //Saved File's Path

private String sFileName; //Saved File's Name

private int nSplitter; //Count of Splited Downloading File

public SiteInfoBean()

{

//default value of nSplitter is 5

this("","","",5);

}

public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)

{

sSiteURL= sURL;

sFilePath = sPath;

sFileName = sName;

this.nSplitter = nSpiltter;

}

public String getSSiteURL()

{

return sSiteURL;

}

public void setSSiteURL(String value)

{

sSiteURL = value;

}

public String getSFilePath()

{

return sFilePath;

}

public void setSFilePath(String value)

{

sFilePath = value;

}

public String getSFileName()

{

return sFileName;

}

public void setSFileName(String value)

{

sFileName = value;

}

public int getNSplitter()

{

return nSplitter;

}

public void setNSplitter(int nCount)

{

nSplitter = nCount;

}

}

/*

**Utility.java

*/

package NetFox;

public class Utility {

public Utility()

{

}

public static void sleep(int nSecond)

{

try{

Thread.sleep(nSecond);

}

catch(Exception e)

{

e.printStackTrace ();

}

}

public static void log(String sMsg)

{

System.err.println(sMsg);

}

public static void log(int sMsg)

{

System.err.println(sMsg);

}

}

/*

**TestMethod.java

*/

package NetFox;

public class TestMethod {

public TestMethod()

{ ///xx/weblogic60b2_win.exe

try{

SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);

//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);

SiteFileFetch fileFetch = new SiteFileFetch(bean);

fileFetch.start();

}

catch(Exception e){e.printStackTrace ();}

}

public static void main(String[] args)

{

new TestMethod();

}

}

iskyshop 2007-11-22

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SiteFileFetch.java负责整个文件的抓取，控制内部线程(FileSplitterFetch类)。
FileSplitterFetch.java负责部分文件的抓取。
FileAccess.java负责文件的存储。
SiteInfoBean.java要抓取的文件的信息，如文件保存的目录，名字，抓取文件的URL等。
Utility.java工具类，放一些简单的方法。
TestMethod.java测试类

/*

**SiteFileFetch.java

*/

package NetFox;

import java.io.*;

import java.net.*;

public class SiteFileFetch extends Thread {

SiteInfoBean siteInfoBean = null; //文件信息Bean

long[] nStartPos; //开始位置

long[] nEndPos; //结束位置

FileSplitterFetch[] fileSplitterFetch; //子线程对象

long nFileLength; //文件长度

boolean bFirst = true; //是否第一次取文件

boolean bStop = false; //停止标志

File tmpFile; //文件下载的临时信息

DataOutputStream output; //输出到文件的输出流

public SiteFileFetch(SiteInfoBean bean) throws IOException

{

siteInfoBean = bean;

//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));

tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");

if(tmpFile.exists ())

{

bFirst = false;

read_nPos();

}

else

{

nStartPos = new long[bean.getNSplitter()];

nEndPos = new long[bean.getNSplitter()];

}

}

public void run()

{

//获得文件长度

//分割文件

//实例FileSplitterFetch

//启动FileSplitterFetch线程

//等待子线程返回

try{

if(bFirst)

{

nFileLength = getFileSize();

if(nFileLength == -1)

{

System.err.println("File Length is not known!");

}

else if(nFileLength == -2)

{

System.err.println("File is not access!");

}

else

{

for(int i=0;i<nStartPos.length;i++)

{

nStartPos[i] = (long)(i*(nFileLength/nStartPos.length));

}

for(int i=0;i<nEndPos.length-1;i++)

{

nEndPos[i] = nStartPos[i+1];

}

nEndPos[nEndPos.length-1] = nFileLength;

}

}

//启动子线程

fileSplitterFetch = new FileSplitterFetch[nStartPos.length];

for(int i=0;i<nStartPos.length;i++)

{

fileSplitterFetch[i] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),

siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),

nStartPos[i],nEndPos[i],i);

Utility.log("Thread " + i + " , nStartPos = " + nStartPos[i] + ", nEndPos = " + nEndPos[i]);

fileSplitterFetch[i].start();

}

// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),

siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);

// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",

nEndPos = " + nFileLength);

// fileSplitterFetch[nPos.length-1].start();

//等待子线程结束

//int count = 0;

//是否结束while循环

boolean breakWhile = false;

while(!bStop)

{

write_nPos();

Utility.sleep(500);

breakWhile = true;

for(int i=0;i<nStartPos.length;i++)

{

if(!fileSplitterFetch[i].bDownOver)

{

breakWhile = false;

break;

}

}

if(breakWhile)

break;

//count++;

//if(count>4)

// siteStop();

}

System.err.println("文件下载结束！");

}

catch(Exception e){e.printStackTrace ();}

}

//获得文件长度

public long getFileSize()

{

int nFileLength = -1;

try{

URL url = new URL(siteInfoBean.getSSiteURL());

HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();

httpConnection.setRequestProperty("User-Agent","NetFox");

int responseCode=httpConnection.getResponseCode();

if(responseCode>=400)

{

processErrorCode(responseCode);

return -2; //-2 represent access is error

}

String sHeader;

for(int i=1;;i++)

{

//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());

//Utility.log(in.readLine());

sHeader=httpConnection.getHeaderFieldKey(i);

if(sHeader!=null)

{

if(sHeader.equals("Content-Length"))

{

nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));

break;

}

}

else

break;

}

}

catch(IOException e){e.printStackTrace ();}

catch(Exception e){e.printStackTrace ();}

Utility.log(nFileLength);

return nFileLength;

}

//保存下载信息（文件指针位置）

private void write_nPos()

{

try{

output = new DataOutputStream(new FileOutputStream(tmpFile));

output.writeInt(nStartPos.length);

for(int i=0;i<nStartPos.length;i++)

{

// output.writeLong(nPos[i]);

output.writeLong(fileSplitterFetch[i].nStartPos);

output.writeLong(fileSplitterFetch[i].nEndPos);

}

output.close();

}

catch(IOException e){e.printStackTrace ();}

catch(Exception e){e.printStackTrace ();}

}

//读取保存的下载信息（文件指针位置）

private void read_nPos()

{

try{

DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));

int nCount = input.readInt();

nStartPos = new long[nCount];

nEndPos = new long[nCount];

for(int i=0;i<nStartPos.length;i++)

{

nStartPos[i] = input.readLong();

nEndPos[i] = input.readLong();

}

input.close();

}

catch(IOException e){e.printStackTrace ();}

catch(Exception e){e.printStackTrace ();}

}

private void processErrorCode(int nErrorCode)

{

System.err.println("Error Code : " + nErrorCode);

}

//停止文件下载

public void siteStop()

{

bStop = true;

for(int i=0;i<nStartPos.length;i++)

fileSplitterFetch[i].splitterStop();

}

}

/*

**FileSplitterFetch.java

*/

package NetFox;

import java.io.*;

import java.net.*;

public class FileSplitterFetch extends Thread {

String sURL; //File URL

long nStartPos; //File Snippet Start Position

long nEndPos; //File Snippet End Position

int nThreadID; //Thread's ID

boolean bDownOver = false; //Downing is over

boolean bStop = false; //Stop identical

FileAccessI fileAccessI = null; //File Access interface

public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException

{

this.sURL = sURL;

this.nStartPos = nStart;

this.nEndPos = nEnd;

nThreadID = id;

fileAccessI = new FileAccessI(sName,nStartPos);

}

public void run()

{

while(nStartPos < nEndPos && !bStop)

{

try{

URL url = new URL(sURL);

HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();

httpConnection.setRequestProperty("User-Agent","NetFox");

String sProperty = "bytes="+nStartPos+"-";

httpConnection.setRequestProperty("RANGE",sProperty);

Utility.log(sProperty);

InputStream input = httpConnection.getInputStream();

//logResponseHead(httpConnection);

byte[] b = new byte[1024];

int nRead;

while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)

{

nStartPos += fileAccessI.write(b,0,nRead);

//if(nThreadID == 1)

// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);

}

Utility.log("Thread " + nThreadID + " is over!");

bDownOver = true;

//nPos = fileAccessI.write (b,0,nRead);

}

catch(Exception e){e.printStackTrace ();}

}

}

//打印回应的头信息

public void logResponseHead(HttpURLConnection con)

{

for(int i=1;;i++)

{

String header=con.getHeaderFieldKey(i);

if(header!=null)

//responseHeaders.put(header,httpConnection.getHeaderField(header));

Utility.log(header+" : "+con.getHeaderField(header));

else

break;

}

}

public void splitterStop()

{

bStop = true;

}

}



/*

**FileAccess.java

*/

package NetFox;

import java.io.*;

public class FileAccessI implements Serializable{

RandomAccessFile oSavedFile;

long nPos;

public FileAccessI() throws IOException

{

this("",0);

}

public FileAccessI(String sName,long nPos) throws IOException

{

oSavedFile = new RandomAccessFile(sName,"rw");

this.nPos = nPos;

oSavedFile.seek(nPos);

}

public synchronized int write(byte[] b,int nStart,int nLen)

{

int n = -1;

try{

oSavedFile.write(b,nStart,nLen);

n = nLen;

}

catch(IOException e)

{

e.printStackTrace ();

}

return n;

}

}