怎样在JAVA中实现断点继传的功能，有没有人知道？

[linger521]

就好象NetAnts那样。

[cxj_2000]

java包中有关于https的连接的

[CanFly]

gz

[xubin_sh]

没有！需要自己实现

[linger521]

怎样实现？或者说说实现断点继传的原理。

[linger521]

没有人知道吗？

[xubin_sh]

Http可以用Range: bytes=xxx-xxx的请求头
Ftp可以用...忘记了
具体你可以看看蚂蚁发送的命令

[kiddycoffee]

以前 CSDN 讨论过的：

(一)断点续传的原理
其实断点续传的原理很简单，就是在Http的请求上和一般的下载有所不同而已。
打个比方，浏览器请求服务器上的一个文时，所发出的请求如下：
假设服务器域名为wwww.sjtu.edu.cn，文件名为down.zip。
GET /down.zip HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-
excel, application/msword, application/vnd.ms-powerpoint, */*
Accept-Language: zh-cn
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)
Connection: Keep-Alive


服务器收到请求后，按要求寻找请求的文件，提取文件的信息，然后返回给浏览器，返回信息如下：


200
Content-Length=106786028
Accept-Ranges=bytes
Date=Mon, 30 Apr 2001 12:56:11 GMT
ETag=W/"02ca57e173c11:95b"
Content-Type=application/octet-stream
Server=Microsoft-IIS/5.0
Last-Modified=Mon, 30 Apr 2001 12:56:11 GMT

　

所谓断点续传，也就是要从文件已经下载的地方开始继续下载。所以在客户端浏览器传给
Web服务器的时候要多加一条信息--从哪里开始。
下面是用自己编的一个"浏览器"来传递请求信息给Web服务器，要求从2000070字节开始。
GET /down.zip HTTP/1.0
User-Agent: NetFox
RANGE: bytes=2000070-
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2


仔细看一下就会发现多了一行RANGE: bytes=2000070-
这一行的意思就是告诉服务器down.zip这个文件从2000070字节开始传，前面的字节不用传了。
服务器收到这个请求以后，返回的信息如下：
206
Content-Length=106786028
Content-Range=bytes 2000070-106786027/106786028
Date=Mon, 30 Apr 2001 12:55:20 GMT
ETag=W/"02ca57e173c11:95b"
Content-Type=application/octet-stream
Server=Microsoft-IIS/5.0
Last-Modified=Mon, 30 Apr 2001 12:55:20 GMT


和前面服务器返回的信息比较一下，就会发现增加了一行：
Content-Range=bytes 2000070-106786027/106786028
返回的代码也改为206了，而不再是200了。


知道了以上原理，就可以进行断点续传的编程了。


(二)Java实现断点续传的关键几点


(1)用什么方法实现提交RANGE: bytes=2000070-。
当然用最原始的Socket是肯定能完成的，不过那样太费事了，其实Java的net包中提供了这种功能。代码如下：
URL url = new URL("http://www.sjtu.edu.cn/down.zip");
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection

　

();
//设置User-Agent
httpConnection.setRequestProperty("User-Agent","NetFox");
//设置断点续传的开始位置
httpConnection.setRequestProperty("RANGE","bytes=2000070");
//获得输入流
InputStream input = httpConnection.getInputStream();


从输入流中取出的字节流就是down.zip文件从2000070开始的字节流。
大家看，其实断点续传用Java实现起来还是很简单的吧。
接下来要做的事就是怎么保存获得的流到文件中去了。


保存文件采用的方法。
我采用的是IO包中的RandAccessFile类。
操作相当简单，假设从2000070处开始保存文件，代码如下：
RandomAccess oSavedFile = new RandomAccessFile("down.zip","rw");
long nPos = 2000070;
//定位文件指针到nPos位置
oSavedFile.seek(nPos);
byte[] b = new byte[1024];
int nRead;
//从输入流中读入字节流，然后写到文件中
while((nRead=input.read(b,0,1024)) > 0)
{
oSavedFile.write(b,0,nRead);
}

怎么样，也很简单吧。
接下来要做的就是整合成一个完整的程序了。包括一系列的线程控制等等。



(三)断点续传内核的实现
主要用了6个类，包括一个测试类。
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。


下面是源程序：
/*
**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;
}


}


/*
**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();
}
}

[kiddycoffee]

借花献佛：:)

如果你比较细心的话，你会发现当用蚂蚁下载的时候，如果把提交者（Referer）属性清空，则用蚂蚁也不能下载了，下载下来的是提醒你的JPG图片……
因为下载的时候，服务器会读取你的Referer属性，然后判断这个属性指向的网址是否属于他的域，是才让你下载，所以，用JAVA写下载程序的时候，记得把这个属性提交就行了……
只需要这样就行：Referer: http://www.9sky.com/9sky2/cd/adddown.asp

根据上面文章中的设置方法，加上这一句就OK了：
httpConnection.setRequestProperty("Referer","http://www.9sky.com/9sky2/cd/adddown.asp");
我还没有试过，不过应该可以的……你试试，不行再说一下，我再看看……
回复人：　bootcool(bootcool)　(2001-8-23 16:06:15) 得0分
我想了一下那个问题，
又查看了netants下载时发送给服务器的信息，
发现关键有一处很重要。
这是netants发送的消息：

2001/08/22 20:33:25 解析主机地址 ...
2001/08/22 20:33:25 主机地址已确认
2001/08/22 20:33:25 连接到主机 (downb.9sky.com:84) ...
2001/08/22 20:33:25 成功连接到主机
2001/08/22 20:33:25 GET /10mp3/248_4310_45680.mp3 HTTP/1.1
2001/08/22 20:33:25 Host: downb.9sky.com:84
2001/08/22 20:33:25 Accept: */*
2001/08/22 20:33:25 Referer: http://www.9sky.com/9sky2/cd/adddown.asp?ss_id=45680&dntype=1&si_cname=玛莉雅%20凯瑞
2001/08/22 20:33:25 User-Agent: Mozilla/4.06 [en] (Win98; I)
2001/08/22 20:33:25 Pragma: no-cache
2001/08/22 20:33:25 Cache-Control: no-cache
2001/08/22 20:33:25 Connection: close
2001/08/22 20:33:25 Range: bytes=51200-

其中提交 Referer:很重要。


这是用socket解决的方法：
import java.io.*;
import java.net.*;

public class HTTPTest {
public HTTPTest(){
}

public static void main(String args[]){
try{
final int PORT =84;
InetAddress ip = InetAddress.getByName("downb.9sky.com");
Socket socket =new Socket(ip,PORT);
BufferedReader in =new BufferedReader(
new InputStreamReader(socket.getInputStream()));
PrintWriter out =new PrintWriter(socket.getOutputStream(),true);
send(out, "GET /10mp3/248_4310_45680.mp3 HTTP/1.1 \r\n"
+"Host: downb.9sky.com:84\r\n"
+"Accept: */*\r\n"
+"Referer: http://www.9sky.com/9sky2/cd/adddown.asp?ss_id=45676&dntype=1&si_cname=玛莉雅%20凯瑞\r\n"
+"User-Agent: NetFox/0.9\r\n"
+"Pragma: no-cache\r\n"
+"Cache-Control: no-cache\r\n"
+"Connection: close\r\n");
String fileline = null;
while((fileline = in.readLine())!=null){
System.out.println(fileline);
}
}
catch(Exception e){}
}

static void send (PrintWriter out, String command)
throws IOException{
out.println(command);
}
}
/////////////////////////////////////////////////////////////////////////////
以下是对作者的程序的一些改进
关键是要设置该下载连接是从哪个网页提交的，即referer。
这样就可以了。只是用户要自己输入referer网页的url,以及要下载的文件的url.
我想一般情况下服务器都不验证是从哪个网页referer过来的。

SiteFileFetch.java

import java.io.*;
import java.net.*;

public class SiteFileFetch implements Runnable {

private SiteInfoBean siteInfoBean = null;
private long[] nStartPos;
private long[] nEndPos;
private FileSplitterFetch[] fileSplitterFetch;
private long nFileLength;
private boolean bFirst = true;
private boolean bStop = false;
private File tmpFile;
private DataOutputStream output;

public SiteFileFetch(SiteInfoBean bean) throws IOException{
siteInfoBean = bean;
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 start(){
Thread t = new Thread(this);
t.start();
try{
t.join(5);
}
catch (Exception exception){}
}

public void run(){
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;
}
}
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();
}

boolean breakWhile = false;

while(!bStop){
write_nPos();
Utility.sleep(100);
breakWhile = true;
for(int i=0;i<nStartPos.length;i++){
if(!fileSplitterFetch[i].bDownOver){
breakWhile = false;
break;
}
}
if(breakWhile){
siteStop();
}
}
System.err.println("文件下载结束！");
}
catch(Exception e){e.printStackTrace ();}
}


public long getFileSize(){
int nFileLength = -1;
try{
URL url= new URL(siteInfoBean.getSSiteURL());
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection();
httpConnection.setUseCaches(false);
httpConnection.setDoOutput(true);
httpConnection.setRequestProperty("GET",url.getFile());
httpConnection.setRequestProperty("Host","downb.9sky.com:84");
httpConnection.setRequestProperty("Accept","*'/'*");
httpConnection.setRequestProperty("Referer","http://www.9sky.com/9sky2/cd/adddown.asp?ss_id=45676&dntype=1&si_cname=玛莉雅%20凯瑞");
httpConnection.setRequestProperty("User-Agent","NetFox");
httpConnection.setRequestProperty("Pragma","no-cache");
httpConnection.setRequestProperty("Cache-Control","no-cache");
httpConnection.setRequestProperty("Connection","close");
int responseCode=httpConnection.getResponseCode();
if(responseCode>=400){
processErrorCode(responseCode);
return -2;
}
String sHeader;
for(int i=1;;i++){
sHeader=httpConnection.getHeaderFieldKey(i);
if(sHeader!=null){
System.out.println(httpConnection.getHeaderField(sHeader));
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;
}

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(fileSplitterFetch[i].nStartPos);
output.writeLong(fileSplitterFetch[i].nEndPos);
}
output.close();
}
catch(IOException e){e.printStackTrace ();}
catch(Exception e){e.printStackTrace ();}
}


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);
}

public void siteStop(){
bStop = true;
for(int i=0;i<nStartPos.length;i++)
fileSplitterFetch[i].splitterStop();
}
}
/////////////////////////////////////////////////////////////////////////
FileSplitterFetch.java
import java.io.*;
import java.net.*;
import java.util.*;

public class FileSplitterFetch extends Thread {

private String sURL;
public long nStartPos;
public long nEndPos;
private int nThreadID;
public boolean bDownOver = false;
private boolean bStop = false;
private FileAccessI fileAccessI = null;

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("http","downb.9sky.com",84,"/10mp3/248_4310_45680.mp3");
URLConnection urlConnection = url.openConnection();
urlConnection.setRequestProperty("GET",url.getFile());
urlConnection.setRequestProperty("Host","downb.9sky.com:84");
urlConnection.setRequestProperty("Accept","*'/'*");
urlConnection.setRequestProperty("Referer","http://www.9sky.com/9sky2/cd/adddown.asp?ss_id=45676&dntype=1&si_cname=玛莉雅%20凯瑞");
urlConnection.setRequestProperty("User-Agent","NetFox");
urlConnection.setRequestProperty("Pragma","no-cache");
urlConnection.setRequestProperty("Cache-Control","no-cache");
urlConnection.setRequestProperty("Connection","close");
String sProperty = "bytes="+nStartPos+"-";
urlConnection.setRequestProperty("RANGE",sProperty);
Utility.log(sProperty);
InputStream input = urlConnection.getInputStream();
byte[] b = new byte[1024];
int nRead;
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
nStartPos += fileAccessI.write(b,0,nRead);
System.out.println(nThreadID+":"+nStartPos);
}
catch(Exception e){e.printStackTrace ();}
}
bDownOver = true;
Utility.log("Thread " + nThreadID + " is over!");
}

public void logResponseHead(HttpURLConnection con){
for(int i=1;;i++){
String header=con.getHeaderFieldKey(i);
if(header!=null)
Utility.log(header+" : "+con.getHeaderField(header));
else break;
}
}

public void splitterStop(){
bStop = true;
}
}

[linger521]

谢谢，不过如果连接协议是https而不是http,如上原理还能行的通吗？

[Dureek]

wa sai ...

[kiddycoffee]

to linger521(chyu)
我也不知道。:(