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java断点续传源代码 java断点续传

用Java实现HTTP断点续传功能(2)

//启动子线程

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fileSplitterFetch = new FileSplitterFetch[nStartPos length];

for(int i= ;ilt;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 ] = new FileSplitterFetch(siteInfoBean getSSiteURL()

siteInfoBean getSFilePath() + File separator + siteInfoBean getSFileName() nPos[nPos length ] nFileLength nPos length );

// Utility log( Thread + (nPos length ) + nStartPos = + nPos[nPos length ] +

nEndPos = + nFileLength);

// fileSplitterFetch[nPos length ] start();

//等待子线程结束

//int count = ;

//是否结束while循环

boolean breakWhile = false;

while(!bStop)

{

write_nPos();

Utility sleep( );

breakWhile = true;

for(int i= ;ilt;nStartPos length;i++)

{

if(!fileSplitterFetch[i] bDownOver)

{

breakWhile = false;

break;

}

}

if(breakWhile)

break;

//count++;

//if(countgt; )

// siteStop();

}

System err println( 文件下载结束!察姿闷 );

 册哪 }

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

}

//获得文件长度

public long getFileSize()

{

int nFileLength = ;

try{

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

HttpURLConnection Connection = (HttpURLConnection)url openConnection ();

( User Agent NetFox );

int responseCode=();

if(responseCodegt;= )

{

processErrorCode(responseCode);

return ; // represent access is error

}

String sHeader;

for(int i= i++)

 败弯 {

//DataInputStream in = new DataInputStream( ());

//Utility log(in readLine());

sHeader=(i);

if(sHeader!=null)

{

if(sHeader equals( Content Length ))

{

nFileLength = Integer parseInt((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= ;ilt;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= ;ilt;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= ;ilt;nStartPos length;i++)

fileSplitterFetch[i] splitterStop();

}

lishixinzhi/Article/program/Java/hx/201311/27070

用java(GUI)实现文件上传与下载,并且可以实现断点续传功能。 (源代码加解释)

这个目前还帮不了你的这个忙,可以尝试用谷歌搜索一下你的提问,也许可以帮到你

JAVA语言,文件传输,实现加密和断点续传功能的程序代码,529162033@qq点抗 好的话加分

package com.down;

import java.io.File;

import com点抗 mon.Common;

import com点抗 mon.ExceptionManager;

public class MainThreadDownFile{

private String url;

private String localsavePath;

private String localsaveName;

private int threadNum;

private static String tempStoreDirectory;//临时文件路径

private long eachThreadSzie;//平均每个线程获取文件的大小

boolean isDownStop=false;

private int entid;

public MainThreadDownFile(int entid,String url,String savePath,String saveName,int threadNum) {

this.entid=entid;

this.url=url;

this.localsavePath=savePath;

this.localsaveName=saveName;

this.threadNum=threadNum;

if(!createDirectory(localsavePath)){ //创建存放附件的地址

Common.WriteLog("创建文件失败!"散滑);

return;

}

}

/**创建存放临碰拿时文件的临冲吵腊时文件夹*/

private String getTempStoreDirectory(String tempDirctoryName){

String tempDirctory = localsavePath +"\\"+ tempDirctoryName;

String tNum = "";

do{

tempDirctory = tempDirctory + tNum;

File file = new File(tempDirctory);

if(file.exists()) tNum = "0";

else return tempDirctory;

} while(true);

}

/**判断是否有存放附件文件夹,如果没有就创建*/

private boolean createDirectory(String localFileAddress){

try{

File file = new File(localFileAddress);

if(!file.exists())

file.mkdir();

}catch(Exception e){

e.printStackTrace();

return false;

}

return true;

}

public void getEachThreadFileSize(long size){

eachThreadSzie=size/threadNum;

}

public boolean checkExistTPFile(){

File file = new File(tempStoreDirectory);

String fileList[] = file.list();

if(fileList.length 0){

for(int i = 0; i fileList.length; i++)

if(fileList[i].indexOf(".tp") 0)

return true;

}

return false;

}

public void init(NetManager nm) throws ExceptionManager{

try{

if(nm.getCode()==200){

String tempDirctoryName="tmp";

DownInfoWriteXml diwx=new DownInfoWriteXml(localsavePath);

String localSaveAddress=diwx.downFileExist(url); //获取临时附件地址

if(localSaveAddress!=null){

this.tempStoreDirectory=localSaveAddress;

}else{

synchronized(this){

tempStoreDirectory=getTempStoreDirectory(tempDirctoryName);

createDirectory(tempStoreDirectory);

diwx.addOneDownRecord(url, tempStoreDirectory);

diwx.saveChange();

}

}

long filesize=nm.getFileSize();

String filename=Common.getSuffixName(nm.getUrlFileName(),"/");

String tempThreadfileName=tempStoreDirectory + "\\" + filename + ".part";

getEachThreadFileSize(filesize);

SingleThreadDownFile[] stdf=new SingleThreadDownFile[threadNum];

long startPos=0L,endPos=0L;

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

if(i1) startPos+=eachThreadSzie;

endPos=startPos+eachThreadSzie;

DownInfo di=new DownInfo(i,url,startPos,endPos);

stdf[i-1]=new SingleThreadDownFile(tempThreadfileName+i);

stdf[i-1].setDi(di);

stdf[i-1].start();

}

String str[]=new String[threadNum];

boolean isStop=true;

DownState ds=new DownState(filesize);

while(isStop){

int n=0;

long fsize=0L;

long totalsize=0L;

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

if(stdf[i-1].isAlive())

fsize += stdf[i-1].downPace;

else n++;

long tsize=new Long(stdf[i-1].downSize);

if(tsize==0){

totalsize += Common.FileSize(tempThreadfileName+i);

}else{

totalsize += tsize;

}

}

if(n==threadNum) isStop=false;

ds.updateDownSize(fsize,totalsize);

ds.init(isStop);

}

if(!checkExistTPFile()!isStop){

FileCombination fc=new FileCombination(url,tempStoreDirectory,localsavePath,localsaveName);

fc.init();

isDownStop=true;

}

}else{

Common.WriteLog(nm.getHttpMessage(nm.getCode()));

}

}catch(Exception e){

throw new ExceptionManager(entid,"出现异常",e);

}

}

}

关于JAVA断点续传

024字节)。第虚斗一次B接收了512字节,那么第二次连接A就应该从513字节开始传输。

也就是说,在第二次传输时,B要提供“我要从513字节开始传送文件F”的信息,然后A使用FileInputStream构建输入流读取本地文件,使用skip(512)方法跳过文件F的前512字节再传送文件,之后B将数据追加(append)到先前接收的文件末尾即可。

进一步考虑,如果要实现多线程传送,即分块传输,也同样的道理。假如B要求差蚂磨分作两块同时传输,那么A启动两个线程,一个从513字节读到768字节(工256字节),第二个线程从769字节到1024字节即可。

如果你要从网络上下载文件,就是说A方不是你实现的,那么你要先确认A方支不支持断电续传功能(HTTP1.1),然后你查阅下HTTP1.1协议,在HTTP1.1版本里,可以通过设置请求包头某个字段的信息(使用URLConnection创建连接并使用setRequestProperty(String key, String value) 方法设置)从而精确读取文件的某一段数据的。注意,基于HTTP断点续传的关键是1.1版本,1.0版本是不支持的。

补充:

嗯,查到了,是设置range属性,即setRequestProperty("range", "bytes=513-1024").你可以使用迅雷下载某个文件,然后从物明”线程信息“中就可以看到这个http1.1断点续传的所有行为信息了。


本文标题:java断点续传源代码 java断点续传
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