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http断点续传简单实现(java)

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/* .K`OEdr<  
**SiteFileFetch.java 3sG7G:4  
*/ ! |SPOk  
package NetFox; )"k>}&'  
import java.io.*; Q#C;4)e  
import java.net.*; &:}e`u@5|  
m|q?gX9R  
' >(])Oq,  
public class SiteFileFetch extends Thread { T}} 0hs;  
i`[5%6\"&  
tHNvb\MR$  
SiteInfoBean siteInfoBean = null; //文件信息Bean W>C!V  
long[] nStartPos; //开始位置 pR_cI]{=SA  
long[] nEndPos; //结束位置 we'<Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n Q|4.e;  
long nFileLength; //文件长度 %Q]u_0P*  
boolean bFirst = true; //是否第一次取文件 &<I*;z6%t  
boolean bStop = false; //停止标志 y,qP$ 5xiq  
File tmpFile; //文件下载的临时信息 >! +.M9  
DataOutputStream output; //输出到文件的输出流 Y.I-h l1<r  
 !sda6?&  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) a<X8l^Ln  
public SiteFileFetch(SiteInfoBean bean) throws IOException &gJKJ=7  
{ z;1y7W!v  
siteInfoBean = bean; y*2R#jTA  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); OJd!g/V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zgp]s+%E  
if(tmpFile.exists ()) ""Ul6hRgv  
{ 8 vNgePn  
bFirst = false; 1-Fg_G}|6  
read_nPos(); nb(4"|8}  
} Z09FW>"u  
else `(A6uakd  
{ 8@%Xd^  
nStartPos = new long[bean.getNSplitter()]; M=[/v/M=  
nEndPos = new long[bean.getNSplitter()]; j]7|5mC78  
} 1xK'1g72  
FFXDt"i2  
/UeLf $%ZW  
';` fMcN  
} pT]M]/y/:  
1|Y(XB^os(  
g-'y_'%0G  
public void run() ".L+gn}u-  
{ -Nmf}`_  
//获得文件长度 WO*yJ`9]  
//分割文件 nPq\J~M  
//实例FileSplitterFetch 2>Kq)Ii  
//启动FileSplitterFetch线程 _dqjRhu  
//等待子线程返回 &QE^i%6>\  
try{ R#~}ZUk2  
if(bFirst) !s,<h U#  
{ etf ft8  
nFileLength = getFileSize(); tYIHsm\b  
if(nFileLength == -1) ~ C5iyXR  
{ x6HebIR+  
System.err.println("File Length is not known!"); cb&y8!ci~  
} |Ix6D  
else if(nFileLength == -2) (Wr;:3i  
{ %9M; MK  
System.err.println("File is not access!"); Z{#^lhHx  
} pALB[;9g  
else EC1q#;:  
{ bI[!y#_z4  
for(int i=0;i<nStartPos.length;i++) fLI@;*hL0  
{ 7qE V5!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {EJVZG:&  
} }=A6Jv(j  
for(int i=0;i<nEndPos.length-1;i++) |U nTd$m  
{ +azPpGZ=  
nEndPos = nStartPos[i+1]; m?<8 ':  
} =)M8>>l  
nEndPos[nEndPos.length-1] = nFileLength; 6AUzS4O  
} {\|? {8f  
} L:Wy- Z  
;YZw{|gsh  
rShi"Yw  
//启动子线程 HKOJkbVZ2^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; IX7d[nm39  
for(int i=0;i<nStartPos.length;i++) 1)_f9GR  
{ I-/PzL<W P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^%_B'X9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9Z*`{  
nStartPos,nEndPos,i); S-2xe?sb  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |Q9S$l]  
fileSplitterFetch.start(); `m2F.^qrr  
} {(a@3m~a%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b@YSrjJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .6O>P2m]a_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O.rk!&N  
nEndPos = " + nFileLength); qgZ(o@\  
// fileSplitterFetch[nPos.length-1].start(); q<c).4  
9q* sR1  
oPa2GW8  
//等待子线程结束 2gt08\  
//int count = 0; #S<>+,Lk  
//是否结束while循环 GQF7]j/  
boolean breakWhile = false; K:'pK1zy  
,?&hqM\  
2#+@bk>^{  
while(!bStop)  )_j.0a  
{ t9m`K9.\  
write_nPos(); K?I@'B'  
Utility.sleep(500); _"WQi}Mm  
breakWhile = true; AO']Kmm  
~S-x-cZ  
|{ 9"n<JW  
for(int i=0;i<nStartPos.length;i++) ?Fi-,4  
{ 8 6L&u:o:  
if(!fileSplitterFetch.bDownOver) <S\S @3  
{ :~T:&;q0  
breakWhile = false; 8kMMQES  
break; R1P,0Yf  
} !5A nr  
} %{}Jr`  
if(breakWhile) R4IFl z  
break;  =_ rn8  
-CL7^  
Q;aZpi-E"  
//count++; 3Ji,n;QLm  
//if(count>4) ;OdUH   
// siteStop(); @L0wd>  
} vxqMo9T  
RIJBHOa  
e9%6+ 9Y  
System.err.println("文件下载结束!"); 5n9F\T5  
} wV-cpJ,}  
catch(Exception e){e.printStackTrace ();} _&dGo(B  
} 'm2,7]  
+i)1 jX<  
_puQX@i  
//获得文件长度 ZnJnjW PQ  
public long getFileSize() + u)'  
{ JGO>X|T  
int nFileLength = -1; LZoth+:  
try{ rBny*!n  
URL url = new URL(siteInfoBean.getSSiteURL()); Ab(bvS8r$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y/$SriC_+'  
httpConnection.setRequestProperty("User-Agent","NetFox"); F8=6!Qj  
Z2$-},i  
94a _ W9  
int responseCode=httpConnection.getResponseCode(); ,U7hzBj8k  
if(responseCode>=400) 3[e@mcO  
{ ;ib~c,  
processErrorCode(responseCode); ?&X6VNbU  
return -2; //-2 represent access is error #JW1JCT  
} P{qn@:  
bX6*/N  
de`6%%|  
String sHeader; DX!$k[  
#15q`w  
M0"feq  
for(int i=1;;i++) t6"4+:c!>  
{ &G"]v]V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -#i%4[v  
//Utility.log(in.readLine()); nut7b  
sHeader=httpConnection.getHeaderFieldKey(i); K3Xy%pqR#  
if(sHeader!=null)  (&gCVf  
{ un /eS-IIh  
if(sHeader.equals("Content-Length")) N&ddO-r[s  
{ (%r:PcGMEV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ze ua`jQ  
break; sV+>(c-$  
} ^Gyl:hN  
} <B fwR$  
else FE5R ^W#u-  
break; 6 S&#8l  
} [Dt\E4  
} %EpK=;51U  
catch(IOException e){e.printStackTrace ();} tT v@8f  
catch(Exception e){e.printStackTrace ();} vd ;wQ  
_9-Ajv  
 AH} nTm  
Utility.log(nFileLength); >:xnjEsi$/  
8jZYy!  
$K iMu  
return nFileLength; q{@Wn]!k  
} '|cuVxcE55  
af_zZf!0  
iIT<{m&`  
//保存下载信息(文件指针位置) j[HKC0C6  
private void write_nPos() p<+]+,|\~:  
{ X-duG*~  
try{ d-* 9tit  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OYzJE@r^  
output.writeInt(nStartPos.length); lAGxE-B^a"  
for(int i=0;i<nStartPos.length;i++) .dfTv/n  
{ ::R^ w"  
// output.writeLong(nPos); b'&pJ1]]}  
output.writeLong(fileSplitterFetch.nStartPos); }Q%>Fv  
output.writeLong(fileSplitterFetch.nEndPos); :.~a[\C@V<  
} 2iGRw4`_a  
output.close(); _5)#{ o<  
} ~ U1iB  
catch(IOException e){e.printStackTrace ();} F>M$|Sc2  
catch(Exception e){e.printStackTrace ();} X XF9oy8  
} a_ P[J8j  
ke%zp-2c  
S ~_%  
//读取保存的下载信息(文件指针位置) 7Y)wu$!7}  
private void read_nPos() j@ "`!uPz  
{ wv7jh~x(4  
try{ OBl8kH(b>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y1~SGg7(@  
int nCount = input.readInt(); V ;6M[ic}  
nStartPos = new long[nCount]; WNx^Rg" >'  
nEndPos = new long[nCount]; U VLcR  
for(int i=0;i<nStartPos.length;i++) !G,$:t1-=V  
{ (H F,p,h_  
nStartPos = input.readLong(); "tark'  
nEndPos = input.readLong(); PHXP1)^}S  
} HB}gn2 .1&  
input.close(); |x4yPYBL  
} sHuz10  
catch(IOException e){e.printStackTrace ();} D 6]$P%t9  
catch(Exception e){e.printStackTrace ();} @r43F$bcqo  
} 5 QeGx3'  
I Q L~I13  
Rf^cw}jU  
private void processErrorCode(int nErrorCode) b>z.d-  
{ z]YhQIU4n8  
System.err.println("Error Code : " + nErrorCode); gh}AD1TN]  
} L1xD$wl  
-FR;:  
OW}A48X[+  
//停止文件下载 "{k )nr+7U  
public void siteStop() 9O Q4\  
{ ZX;k*OrW  
bStop = true; =QfKDA  
for(int i=0;i<nStartPos.length;i++) {|h"/   
fileSplitterFetch.splitterStop(); h%s  
\?^wu  
713M4CtJ  
} O-5U|wA  
} [8P2V  
//负责部分文件的抓取 Q75^7Ga_  
**FileSplitterFetch.java WS/+Yl  
*/ +I n"OR%  
package NetFox; \Ji2u GT  
mv.I.EL  
xUpb1 R  
import java.io.*; *`-29eR"8  
import java.net.*; d-sh6q5  
h3EDN:FQ  
-l@W)?$  
public class FileSplitterFetch extends Thread { $tHwJ!<$&  
PJ@,01  
ls\E%d  
String sURL; //File URL p.] .M"A  
long nStartPos; //File Snippet Start Position %QgAilj,  
long nEndPos; //File Snippet End Position Sc$wR{W<:  
int nThreadID; //Thread's ID #ljg2:I+  
boolean bDownOver = false; //Downing is over Qf>Pb$c$U  
boolean bStop = false; //Stop identical FqxOHovE  
FileAccessI fileAccessI = null; //File Access interface ,M&0<k\  
}!<cph  
F` 5/9?;|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 25c!-.5D  
{ + 4g%?5'  
this.sURL = sURL; <1+6O[>{  
this.nStartPos = nStart; F]A~~P  
this.nEndPos = nEnd; 7 eQoc2X2  
nThreadID = id; m'(;uR`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6q[!X0u  
} `ab\i`g9  
(g/X(3  
?U/Wio$@  
public void run() kqvJ&7  
{ FT/5 _1i  
while(nStartPos < nEndPos && !bStop) if[o?6U4t  
{ >_aio4j}r  
tP Efz+1N  
sMS9!{A  
try{ U?F^D4CV\  
URL url = new URL(sURL); #f3;}1(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bjPbl2K  
httpConnection.setRequestProperty("User-Agent","NetFox"); -iDEh_pts  
String sProperty = "bytes="+nStartPos+"-"; NC.P 2^%  
httpConnection.setRequestProperty("RANGE",sProperty); EdAR<VfleA  
Utility.log(sProperty); }\939Y  
Ls>u` hG  
f>)Tq'  
InputStream input = httpConnection.getInputStream(); X`3vSCn  
//logResponseHead(httpConnection); ,B~lwF9  
h lkvk]v  
[%84L@:h  
byte[] b = new byte[1024]; ,|. *,  
int nRead; BgkB x  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |)?aH2IL  
{ Z cTL#OTP  
nStartPos += fileAccessI.write(b,0,nRead); ]]uzl0LH  
//if(nThreadID == 1) HZDaV&)@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B)"#/@!bHH  
} ].-J.  
[-E{}FL|  
(K*/Vp  
Utility.log("Thread " + nThreadID + " is over!"); 6MQs \J6.  
bDownOver = true; XSp x''l  
//nPos = fileAccessI.write (b,0,nRead); QtnM(m  
} <84C tv  
catch(Exception e){e.printStackTrace ();} /lr1hW~Dbk  
} {UdcX~\~  
} xTJ Sr2f  
*>aZc::  
>[|GC/C  
//打印回应的头信息 L}}=yh6r  
public void logResponseHead(HttpURLConnection con) i'W_;Y}  
{ {d 1N&  
for(int i=1;;i++) H@%7\g,`  
{ R=vbUA  
String header=con.getHeaderFieldKey(i); 8h&oSOkQk,  
if(header!=null) 9h:jFhsA9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); c<=`<!FS[  
Utility.log(header+" : "+con.getHeaderField(header)); dThR)Z'=  
else Rwc[:6;fn  
break; Q7~'![(a  
} t7um [  
} v8=?HUDd  
{D_++^  
a>o"^%x  
public void splitterStop() pqyWv;  
{ .'t (-eT,  
bStop = true; :3KO6/+  
} 6=ZRn gQ  
M82.khm~jM  
S}oG.r 9  
} = n+q_.A  
A Gv!c($  
RLdl z  
/* 5f;n<EP y  
**FileAccess.java &$mZ?%^C  
*//文件访问(定位,写) yGb a  
package NetFox; 2y3?!^$  
import java.io.*; 0JmFQ ^g(  
B#FHf Z  
b;S6'7Jf9  
public class FileAccessI implements Serializable{ J.1O/Pw!.a  
<RhOjZgyZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 To3^L_v"  
RandomAccessFile oSavedFile; CQ@LmTW[  
long nPos; &MCy.(jN  
FX H0PK  
`TUZZz  
public FileAccessI() throws IOException <^d!Vzr]  
{ ^'m\D;  
this("",0); TqIAWbb&  
} Z:K+I+:t  
*i@sUM?K  
%1Yz'AiW[  
public FileAccessI(String sName,long nPos) throws IOException k/%#>  
{ kW#S]fsfU  
oSavedFile = new RandomAccessFile(sName,"rw"); r]v&t  
this.nPos = nPos; !_qskDc-  
oSavedFile.seek(nPos); xpF](>LC(  
} e|yX QTlvL  
v2d<o[[C  
9X(Sk%  
public synchronized int write(byte[] b,int nStart,int nLen) (B@X[~  
{ ^V[/(Lq  
int n = -1; d^PD#&"g  
try{ 1Q]Rd  
oSavedFile.write(b,nStart,nLen); )B6# A0  
n = nLen; cv2]*  
} ',GV6kt_k  
catch(IOException e) @<2d8ed  
{ u#1%P5r&X  
e.printStackTrace (); +=7:4LFOL  
} _g[-=y{Bb  
y,Jh@n';|  
w!\3ICB  
return n; {(4# )K2g%  
} (?vK_{  
%<ic%gt`#  
joqWh!kv7U  
} /be=u@KV  
^-hErsK  
Y&K <{\vE  
/* +c--&tBo  
**SiteInfoBean.java \@K~L4>  
*/ 3Hw[s0[$  
package NetFox;  ;\qXbL7  
 Hy]  
\7Qb229?  
public class SiteInfoBean { -p`L% xj\  
%m eLW&  
_1aGtX|W  
private String sSiteURL; //Site's URL :'}@Al9=>  
private String sFilePath; //Saved File's Path _\\ -md:  
private String sFileName; //Saved File's Name RP! X8~8  
private int nSplitter; //Count of Splited Downloading File %?9Ok  
:_xh(W+2<  
oZN'H T  
public SiteInfoBean() /1d<P! H  
{//nSplitter的缺省值为5 [}-3PpF  
//default value of nSplitter is 5 jAC78n,Fi@  
this("","","",5); W\8Ln>  
} BtsdeLj|  
+Rwx% =  
e)@3m.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7&U&E|  
{ Y/fJQ6DY  
sSiteURL= sURL; w<NyV8-hL  
sFilePath = sPath; .Q* 'r& n  
sFileName = sName; U]R~gy}#  
this.nSplitter = nSpiltter; =sgdkAYwP  
rjk( X|R*  
0 )}$^TV  
} /Vww?9U;  
D#Kuo$  
n?xTkkr0  
public String getSSiteURL() s^hR\iY  
{ iPj~I  
return sSiteURL; }^%xvmQ\]  
} eSfnB_@x2  
-SCM:j%h  
28I^$> [  
public void setSSiteURL(String value) h4)Bs\==mT  
{ w0lT%CPx  
sSiteURL = value; `@Oa lg  
} `<frgXu64  
F<|t\KOW  
@'6"7g  
public String getSFilePath() vFv3'b$;G  
{ i=S~(gp  
return sFilePath; p3(2?UO!  
} cU.9}-)  
vB'>[jvA|  
'b&yrBFD  
public void setSFilePath(String value) ?C-Towo=i  
{ u<xo/=Z  
sFilePath = value; E_T 2z4lw  
} neZ.`"LV  
}baR5v  
QzvHm1,@  
public String getSFileName() `G9 l  
{ iUi>y.}"P  
return sFileName; hX:"QXx  
} }H> ^o9  
!69&Ld  
aB~S?.l  
public void setSFileName(String value) Z<?OwAWz  
{ sgUud_r)4  
sFileName = value; 2,q}N q  
} $'rG-g!f\  
=q7Z qP  
')Y'c  
public int getNSplitter() ia@'%8  
{ : rMM4  
return nSplitter; Zdc63fllM  
} Pz*_)N}j >  
dP?Ge}  
b?X.U}62_  
public void setNSplitter(int nCount) u$#Wv2|mk  
{ pKiZ)3U  
nSplitter = nCount; Fb22p6r  
} ~}EMk3  
} GPz(j'jU  
Ysq'2  
>@xrs  
/* JxE53ev  
**Utility.java ]V l]XT$Um  
*/ t7 n(Qkrv  
package NetFox; nRL. ppUI  
NX`*%K  
)c n+1R  
public class Utility { X+L) -d  
>(uZtYM\j  
g8qgk:}  
public Utility() ('wY9kvL&  
{ [[PEa-992  
IG)s^bP  
;<yd^Xs  
} ];'v8)Y  
`>0MNmu  
//线程睡眠 NH$r Z7$  
public static void sleep(int nSecond) JD@J[YY5R  
{ kB?al#`  
try{ &j(+/;A  
Thread.sleep(nSecond); d ;vT ~;  
} \fA{1  
catch(Exception e)  .ObZ\.I  
{ MZ Aij  
e.printStackTrace (); 3"o"fl  
} (Yp+bS(PU*  
} .>Ljnk  
x77l~=P+!  
//日志 !x!07`+^u  
public static void log(String sMsg) 64hk2a8  
{ :'#TCDlOb  
System.err.println(sMsg); K>*a*[t0Sy  
} ,%\o4Rc'o  
:0s]U_h  
=Umw$+fJr  
public static void log(int sMsg) O_Oj|'bBC  
{ v) vkn/:  
System.err.println(sMsg); TMY d47  
} `rf_7  
} z dO#0t N  
J_s>N  
@|Rrf*J?%  
/* M5xCC!  
**TestMethod.java 5 ~TdD6}  
*/ um9_ru~  
package NetFox; _i/t?7  
Mbjvh2z  
H^YSJ 6  
public class TestMethod { ]c! ;L5  
<~ Sz04  
=$]uoA  
public TestMethod() hWX% 66  
{ ///xx/weblogic60b2_win.exe _q~=~nub  
try{ m=YU2!Mb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _cXqAo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $m42:amM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); OF\rgz  
fileFetch.start(); ?M[ A7?  
} :_O%/k1\@  
catch(Exception e){e.printStackTrace ();} k{'0[,mx#  
Y.*y9)#S6  
rwGKfoKI  
} j$+nKc$  
7}X[ 4("bB  
t+eVR8  
public static void main(String[] args) 2$Tj84'X  
{ Z,=7Tu bR#  
new TestMethod(); }mAa}{_  
} /n>qCuw  
} ,lyb!k8  
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