http断点续传简单实现（java)

/* iFpJ/L  
**SiteFileFetch.java /JJU-A(  
*/ #pLd';  
package NetFox; Kk-A?ju@g  
import java.io.*; H:2#/1Oz>  
import java.net.*; LLCMp3qBz  
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public class SiteFileFetch extends Thread { R{u/r%  
}fdo Aid~  
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SiteInfoBean siteInfoBean = null; //文件信息Bean e0qU2  
long[] nStartPos; //开始位置 !5&% P b  
long[] nEndPos; //结束位置 hjs[$,1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 fpu^  
long nFileLength; //文件长度 ]|'Mf;  
boolean bFirst = true; //是否第一次取文件 r+ k5Bk'  
boolean bStop = false; //停止标志 oF8#gn_  
File tmpFile; //文件下载的临时信息 (@[c;+x  
DataOutputStream output; //输出到文件的输出流 %,1bh  
=UT*1-yhR  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） yMB*/vs  
public SiteFileFetch(SiteInfoBean bean) throws IOException xXQDHc-Ba  
{ kg1z"EE  
siteInfoBean = bean; @.@O#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); UTC|8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $QN}2lJ>  
if(tmpFile.exists ()) #[ipJ %  
{ { LZ` _1D  
bFirst = false; >+LFu?y  
read_nPos(); R$sG*=a!8j  
} 9/'zk
  
else [AA'Ko  
{ *`7cvt5]IM  
nStartPos = new long[bean.getNSplitter()]; %dw@;IZ#8{  
nEndPos = new long[bean.getNSplitter()]; fIWOo >)D  
} 4'_PLOgnX  
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<#k(g\/R  
n j0!  
} tUaDwIu#  
2= S;<J
 
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public void run() <xv@us7  
{ GAI(=  
//获得文件长度 Y|stxeOC  
//分割文件 H$^IT#  
//实例FileSplitterFetch 3\JEp,5  
//启动FileSplitterFetch线程 Xt& rYv  
//等待子线程返回 dn!#c=  
try{ .?|pv}V  
if(bFirst) !,WO]Ov  
{ gn4+$f~w  
nFileLength = getFileSize(); g]%sX6T  
if(nFileLength == -1) .EpcMXT%  
{ cdY|z]B  
System.err.println("File Length is not known!"); >PHin%#  
} z3>ldT  
else if(nFileLength == -2) 7|bzopLJk  
{ mhpaPin*JS  
System.err.println("File is not access!"); }g&A=u_2  
} %s&l^&
ux  
else N/CL?Z>c  
{ ny'?Hl'Q  
for(int i=0;i<nStartPos.length;i++) U|yXJ.Z3  
{ vM5yiHI(jb  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); KFZ2%:
6>  
} QmxI;l  
for(int i=0;i<nEndPos.length-1;i++) _[IOPHa"  
{ /z
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nEndPos = nStartPos[i+1]; ;=r_R!
d@  
} {^(h*zxn  
nEndPos[nEndPos.length-1] = nFileLength; fXD9w1  
} `-yo-59E[  
} Fp=O:]  
zp.-=)D4e  
#O<,  
//启动子线程 ;D'6sd"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;xqN#mqq  
for(int i=0;i<nStartPos.length;i++) N5K\h}'%  
{ Z8 eB5!$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'ip2|UG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (+aU,E
Q  
nStartPos,nEndPos,i); P]cC2L@Vbi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bSJ@ 5qS  
fileSplitterFetch.start();
'/O >#1  
} ^W#161&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `|&#=hl~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7F$G.LhMw  
nEndPos = " + nFileLength); 2;2FyKF(  
// fileSplitterFetch[nPos.length-1].start(); ^?<gz!(-  
h$`zuz  
05SK$ Y<<  
//等待子线程结束 h[*:\P`  
//int count = 0; q#
C;i
K4  
//是否结束while循环 %7}ibz4iF  
boolean breakWhile = false; tleWJR8oc  
>8;EeRvI  
>>nOS]UL  
while(!bStop) C"7-lz  
{ yX7P5c.   
write_nPos(); fmgXh)=  
Utility.sleep(500); CqFk(Td9-D  
breakWhile = true; ag02=}Q'r  
2e_m>I  
#EG$HX]  
for(int i=0;i<nStartPos.length;i++) wa1Qt  
{ y\?NB:=%  
if(!fileSplitterFetch.bDownOver) 9@3cz_[J  
{ %r =9,IJ  
breakWhile = false; 0^('hS&  
break; omu)s '8  
} xu<oQBt  
} ^7l+ Ofb3  
if(breakWhile) z ?L]5m`H  
break; }e
bu@)r  
{J~VB~('  
OrPi ("/  
//count++; 8.WZC1N  
//if(count>4) $ VTk0J-W  
// siteStop(); ;)Fc@OXN>  
} W @ ?*~  
X+
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Qo\+FkhYq  
System.err.println("文件下载结束！"); &RB{0Q
hx  
} &*j# [6  
catch(Exception e){e.printStackTrace ();} Q'~3Ik  
}  -^ceTzW+  
+?9. &<?  
7MZ(tOR  
//获得文件长度 as^!c!  
public long getFileSize() G0h/]%I  
{ qw<~v?{|C  
int nFileLength = -1; qxbGUyH==  
try{ T/$hN hQK  
URL url = new URL(siteInfoBean.getSSiteURL()); FKWL{"y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wN]]t~K)Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); '5etZ!
:  
1fMl8[!JLu  
D}T+X;u)K  
int responseCode=httpConnection.getResponseCode(); It#T\fU  
if(responseCode>=400) 3]rd!Gp=*  
{ Mwtd<7<!A  
processErrorCode(responseCode); V:'_m'.-Y  
return -2; //-2 represent access is error M$Or|HT
G  
} $+WMKv@<  
l1UN.l'p  
~O8Xj6  
String sHeader; H^fErl  
k#"}oI{< 6  
(|dN6M-.K  
for(int i=1;;i++) R>B4v+b  
{ K<E|29t^k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *pSD[E>SU  
//Utility.log(in.readLine()); AQgagE^  
sHeader=httpConnection.getHeaderFieldKey(i); z8JdA%YBM  
if(sHeader!=null) Nhrh>x[wJ  
{ hZtJ
LY  
if(sHeader.equals("Content-Length")) 1X-fiQJe  
{ G[lNgVbU@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); C^ 1;r9  
break; <IwfiI3y  
} |Ye%HpTTv  
} |5g1D^b]s^  
else o2_mcJ  
break; +Z/aB*aVa^  
} iM_Zn!|@\  
} q[
5&  
catch(IOException e){e.printStackTrace ();} f9a_:]F   
catch(Exception e){e.printStackTrace ();} chszP{-@X  
bM>5=Zox  
' }T6dS  
Utility.log(nFileLength); wvz_)bN~A  
cr>"LAi  
a&C}'e"  
return nFileLength; &O\$=&, h  
} Al^h^ 9tJ  
h e1=  
vv^(c w>A  
//保存下载信息（文件指针位置） 8/T,.<5  
private void write_nPos() C@OY)!x!  
{ ^"{txd?6  
try{ s5
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output = new DataOutputStream(new FileOutputStream(tmpFile)); :d}@Z}2sD  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) |m>{< :  
{ Zp_v
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// output.writeLong(nPos); EL:Az~]V  
output.writeLong(fileSplitterFetch.nStartPos); uoMDf{d  
output.writeLong(fileSplitterFetch.nEndPos); vN$j@h .  
} ;S}_/'  
output.close(); =*=qleC3  
} Zd<8c^@  
catch(IOException e){e.printStackTrace ();} @f%q ,:  
catch(Exception e){e.printStackTrace ();} @ $2xiE.[  
} aP`V  
q%hxU.h  
!_pryNcb  
//读取保存的下载信息（文件指针位置） IiB"F<&[j{  
private void read_nPos() +^<-;/FZue  
{ +ieRpVg  
try{ UlH;0P?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); vI0::ah/  
int nCount = input.readInt(); Y~g*"J5j  
nStartPos = new long[nCount]; >Ni<itze$i  
nEndPos = new long[nCount]; g/BlTi
 
for(int i=0;i<nStartPos.length;i++) "2>_eZ#b  
{ C,G$C7$
%  
nStartPos = input.readLong(); -Ou@T#h"  
nEndPos = input.readLong(); zOT(>1'  
} u 4$$0 `  
input.close(); e
gh_1Wg2a  
} sHf.xc  
catch(IOException e){e.printStackTrace ();} e!p?~70  
catch(Exception e){e.printStackTrace ();} HK4 *+  
} 0})mCVBY  
X.FFBKjf[e  
Y4,LXuQ
 
private void processErrorCode(int nErrorCode) 1%k$9[!l%  
{ kdp- 
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System.err.println("Error Code : " + nErrorCode); +kZW:t!-  
} [O\[,E"K  
#7"*Pxb#A  
U9%#(
T$  
//停止文件下载 ofHe8a8  
public void siteStop() NTy0NH  
{ |^T?5=&Kt  
bStop = true; $^louas&  
for(int i=0;i<nStartPos.length;i++) +Q!  
fileSplitterFetch.splitterStop(); 5~E'21hJ  
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/><+[\q4LM  
} {n-6e[  
} ?nV& :~eY  
//负责部分文件的抓取 THf*<
|  
**FileSplitterFetch.java QTbv3#  
*/ 9vw0box  
package NetFox; '.1_anE]  
h+d3JM  
A-5'OI  
import java.io.*; V7q-Pfh!y  
import java.net.*; g!.k>  
|}2X|4&X  
~E*`+kD  
public class FileSplitterFetch extends Thread { ,{VC(/d  
I+g[ p  
`&!J6)OJ  
String sURL; //File URL JsyLWv@6xa  
long nStartPos; //File Snippet Start Position %:vMD  
long nEndPos; //File Snippet End Position 1PnWgu  
int nThreadID; //Thread's ID mQqv{1  
boolean bDownOver = false; //Downing is over u
!DAeE  
boolean bStop = false; //Stop identical 6%t>T~x  
FileAccessI fileAccessI = null; //File Access interface 7<7 /NZ<I  
2SlOqH1  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException UCL aCt -  
{ cr"AK"TQ  
this.sURL = sURL; g1B[RSWv  
this.nStartPos = nStart; xji2#S%  
this.nEndPos = nEnd; V]qv,>  
nThreadID = id; Sz#dld Mz  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J-)9>~[E<  
} /4lm=ZE/  
\aB>Q"pS  
+ht{ARX2(  
public void run() v5`Q7ZZ  
{ m[%
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while(nStartPos < nEndPos && !bStop) /R!/)sg  
{ 3 F ke#t  
}J-+^  
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try{ c037#&Q%#  
URL url = new URL(sURL); )%D>U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i_kKE+Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); 76j5  
String sProperty = "bytes="+nStartPos+"-"; FatLc|[  
httpConnection.setRequestProperty("RANGE",sProperty); (S=RFd  
Utility.log(sProperty); QGM@m:O  
P_8z'pYd>  
R1lC_G]  
InputStream input = httpConnection.getInputStream(); YNV4'  
//logResponseHead(httpConnection); LH]<+Zren  
iw)^;8q  
eSlZAdK  
byte[] b = new byte[1024]; S=.7$PY  
int nRead; :$gR >.`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  Re^~8q[  
{ f9FLtdh \7  
nStartPos += fileAccessI.write(b,0,nRead); I|oS`iLl$  
//if(nThreadID == 1) l1MVC@'pvP  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l\%LT{$e  
} Vp~c$y+  
]F81N(@:F  
$bd2TVNV:  
Utility.log("Thread " + nThreadID + " is over!"); E3==gYCe*  
bDownOver = true; ~qj09  
//nPos = fileAccessI.write (b,0,nRead); @.SuHd  
} oo{3-+ ?  
catch(Exception e){e.printStackTrace ();} ne(zGJd  
} 9/_F  
} \n`)>-  
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!Ey=  
//打印回应的头信息 ^qP}/H[QT  
public void logResponseHead(HttpURLConnection con) 32KL~32Y  
{ UoSzxL  
for(int i=1;;i++) c>3AR17+5  
{ F#^<t$5t  
String header=con.getHeaderFieldKey(i); 1YxG<K]  
if(header!=null) {} gr\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "x P2GZ  
Utility.log(header+" : "+con.getHeaderField(header)); 1*o=I-nOa  
else l=.h]]`;  
break; j|/4V  
} a/v!W@Zz}  
} X:
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}aC@ov]2  
C~:@ETcbil  
public void splitterStop() DtrR< &m  
{ ~vMdIZ.h  
bStop = true; g!*5@k|C  
} 7Fd`MTo  
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r3_O?b  
} yoc;`hO-  
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iF#|Z$g-(  
/* 2V6kCy@V  
**FileAccess.java eK)R=M@i  
*//文件访问(定位，写) ]:X# w0UR  
package NetFox; <*'%Xgm  
import java.io.*; $wBF'|eU  
znxP.=GB   
j[e<CGZ  
public class FileAccessI implements Serializable{ 1O{(9nNj  
8uZM%7kI6+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fKYRDGn  
RandomAccessFile oSavedFile; _b)=ERBbCo  
long nPos; *`g'*R  
!um~P  
b2<((H  
public FileAccessI() throws IOException P56B~M_  
{ Uzzt+Iwm  
this("",0); <QcQ.b  
} .nG14i7C  
6J""gyK.  
)5NjwL
s  
public FileAccessI(String sName,long nPos) throws IOException tzn+ M0'  
{ lH#C:n  
oSavedFile = new RandomAccessFile(sName,"rw"); iT2
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this.nPos = nPos; .4&pi  
oSavedFile.seek(nPos); ^ b`wf"A  
} 2f8\Osn>m  
KyQd6 1  
4J9VdEKk  
public synchronized int write(byte[] b,int nStart,int nLen) Q%*987i  
{ d(X/N2~g  
int n = -1; HkL`- c0  
try{ vv FH (W  
oSavedFile.write(b,nStart,nLen); aF!Im}  
n = nLen; \Hs*46@TC  
} |@*3 nb8  
catch(IOException e) Ua2waA  
{ wS"`~Ql_  
e.printStackTrace (); Dm+[cA"I  
} *&nIxb60b{  
BJNZH#"  
H,q-*Kk  
return n; ;rqW?':(i  
} 9m+ejTK{U  
km,I75o.  
!-cK@>.pE  
} GVKc4HGt  
1&.q#,EMn(  
uK;&
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/* FD[o94`%  
**SiteInfoBean.java V7}]39m(s  
*/ =73aME}  
package NetFox; nQaryL  
ZR8
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q*'-G]tH=  
public class SiteInfoBean { 8W"Xdv{  
\WPy9kRU  
gCL?{oVU  
private String sSiteURL; //Site's URL S\dG>F>S  
private String sFilePath; //Saved File's Path /:.p{y  
private String sFileName; //Saved File's Name r"&uW!~0  
private int nSplitter; //Count of Splited Downloading File b'1m 9T780  
%+: $uk[  
>*]dB|2  
public SiteInfoBean() yE_T#FN  
{//nSplitter的缺省值为5 UY}EW`$#m  
//default value of nSplitter is 5 3'zL,WW  
this("","","",5); nIEIb.-  
} 4L_AhX7  
n3" @E<rW  
7I=vgT1F  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
qp{3I("_  
{ V M{Sng  
sSiteURL= sURL; J
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sFilePath = sPath; S[5OTwa8L  
sFileName = sName; #DA,*  
this.nSplitter = nSpiltter; K +l-A>Ic  
U9Gg#M4tY  
vtw97G  
} ecMpU8}rR  
Ie7S'.Lmq  
q${+I(b,  
public String getSSiteURL() n3_|#1Qu  
{ %{B4M#~  
return sSiteURL; KSve_CBOh  
} 6ee1^>  
rKkFflOVO  
:/\KVz'fw}  
public void setSSiteURL(String value) DCSmEy`.  
{ ^~kfo|  
sSiteURL = value; 9|l6.$Me/  
} d04fj/B  
t;b1<TLn0  
5;CqGzgoP  
public String getSFilePath() >>T,M@s-:  
{ nU23D@l  
return sFilePath; ?6V U4nK/*  
} /}Ct2w&<k  
Q;k D Jo  
},%,v2}  
public void setSFilePath(String value) l<UA0*t  
{ 4bq+(CI6  
sFilePath = value; \F9HsR6  
} 6g)X&pZ  
}*|aVBvU  
)&[Zw{6P  
public String getSFileName() +%H2;8{F  
{ :v%iF!+.P  
return sFileName; Q94p*]W"  
} ow7*HN*  
c8oE,-~  
+:3p*x%1H  
public void setSFileName(String value) )VeeAu)p  
{ L"'L@A|U  
sFileName = value; @N6KZn|R  
} nnuJY$O;M  
|k<5yj4?  
~EO=;a_  
public int getNSplitter() ge[&og/$  
{ 97n,^t2F\  
return nSplitter; <ahcE1h  
} ZW ZKyJQ  
qz }PTx  
A&C?|M?M  
public void setNSplitter(int nCount) ?jn";:  
{ N6h.zl&04  
nSplitter = nCount; *lyRy/POB  
} y<^hM6S?Z  
} i)[~]D.EH8  
Q32GI,M%B  
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/* DIWcX<s  
**Utility.java kYu"`_n}  
*/ mU;\,96#  
package NetFox; E@8&#<  
$*;ke5Dm4  
_))--+cL  
public class Utility { kjRL|qx`a;  
*W<|5<<u@  
Za'
}26  
public Utility() eXQzCm  
{ [p96H)8YU  
}^ZPah  
ca"20NQ)  
} Y4)=D@JI  
2^fSC`!  
//线程睡眠 u<nPJeE  
public static void sleep(int nSecond) p 4Y2AQ9  
{ to3D#9Ep  
try{ c59l/qoz  
Thread.sleep(nSecond); d~w}{LR[1  
} /;9]LC.g  
catch(Exception e) 0[!38  
{ ''wF%q  
e.printStackTrace (); ;op
8r u  
} gro@+^DmT  
} +$D~?sk  
f/]g@/`  
//日志 +"D*0gYD  
public static void log(String sMsg) sRSy++FRF  
{ T0lbMp
 
System.err.println(sMsg); Z$ 6yB  
} H:`
[$ ^  
h7[PU^m  
nX-%qc"  
public static void log(int sMsg) B#K2?Et!t  
{ 
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System.err.println(sMsg); psAdYEGk!  
} :a y-2  
} ^?gs<-)B  
Cs8e("w  
=@go;,"  
/* ;T?4=15c  
**TestMethod.java I~NQt^sg  
*/ 3&7$N#v  
package NetFox; H
v<jf38  
pax;#*QcQ  
m'ykDK\B  
public class TestMethod { *m`KY)b=l  
AV^Sla7|_  
^n8r mh_%  
public TestMethod() NRZ>03w  
{ ///xx/weblogic60b2_win.exe 3qBZzM O*  
try{ @M]7',2"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); yf7$m_$C'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MYF6tZ*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); nh+f,HtSt  
fileFetch.start(); . [5{  
} "jEf$]  
catch(Exception e){e.printStackTrace ();} jwZBWt )5  
w65D;9/;  
pm}!?TL  
} &[4lP~  
Z}4 `y"By  
4O** %!|  
public static void main(String[] args) }dO^q-t$3  
{ 9?#L/  
new TestMethod(); K\`>'C2_V  
} J\x.:=V  
} WZJ}HHePr  
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