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http断点续传简单实现(java)

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/* j?a^fcXB  
**SiteFileFetch.java Q7uhz5oZ  
*/ ;A^Ii>`  
package NetFox; t2V|moG  
import java.io.*; w Q!C9Gp3e  
import java.net.*; 9p| ;Hh:  
Z{<&2*  
IpX.ube  
public class SiteFileFetch extends Thread { l\+^.ezD  
)bCw~'h*  
@APv?>$)  
SiteInfoBean siteInfoBean = null; //文件信息Bean F\LAw#IJ  
long[] nStartPos; //开始位置 =QG@{?JTl  
long[] nEndPos; //结束位置 )?es3Ehqq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 jhU'UAn  
long nFileLength; //文件长度 Vqr#%. N  
boolean bFirst = true; //是否第一次取文件 xw[KP [(  
boolean bStop = false; //停止标志 4}C^s\?z  
File tmpFile; //文件下载的临时信息 1< 22,  
DataOutputStream output; //输出到文件的输出流 IY$v%%2WZ  
L;jzDng<  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) :x85:pa  
public SiteFileFetch(SiteInfoBean bean) throws IOException t]dtBt].:  
{ LU'<EXUbY  
siteInfoBean = bean; oll J#i9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); O{YT6&.S0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -|Z[GN:  
if(tmpFile.exists ()) O}$@|w(8;  
{ V5ve  
bFirst = false; ST'eJ5P7!5  
read_nPos(); b@6hGiqx  
} T'W)RYnwl  
else 8OV;&Z,x  
{ j6Msbq[  
nStartPos = new long[bean.getNSplitter()]; ^r4@C2#vzJ  
nEndPos = new long[bean.getNSplitter()]; \PHbJN:BI  
} SQ$|s%)oB  
c*fMWtPp  
qIXo_H&\C  
,# i@jB  
} x}\_o< d  
32#|BBY  
L$T23*9XY  
public void run() BC*)@=7fx  
{ 4gyC?#Ede  
//获得文件长度 j.}@9  
//分割文件 |_fmbG  
//实例FileSplitterFetch O $ p  
//启动FileSplitterFetch线程 'aj97b;lpG  
//等待子线程返回 cOhx  
try{ ,drbj.0-  
if(bFirst) \&tv *  
{ d'bAM{R>  
nFileLength = getFileSize(); 0O@UT1 M;v  
if(nFileLength == -1) f}1B-  
{ h mijp1u  
System.err.println("File Length is not known!"); VR5CRNBJ  
} B4uJT~,7>  
else if(nFileLength == -2) ]6)~Sj$ 5  
{ WR5@S&fU`  
System.err.println("File is not access!"); $9~6M*  
} F0Nl,9h('  
else whoM$  &  
{ ( L{>la!  
for(int i=0;i<nStartPos.length;i++) QB3vp4pBg@  
{ =x_~7 Xc{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); rzl0*CR  
} x-hr64WFK  
for(int i=0;i<nEndPos.length-1;i++)  /y2)<{{I  
{ zc1y)s0G  
nEndPos = nStartPos[i+1]; Y.7iKMp(  
} !PAuMj)P  
nEndPos[nEndPos.length-1] = nFileLength; d3,%Z &  
} ~tw#Q  
} dq6|m }g{  
D]P_tJI  
pUp&eH  
//启动子线程 T6Oah:50EM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bi01]  
for(int i=0;i<nStartPos.length;i++) #L3heb&9  
{ F\K&$5J{p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t@_MWF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5*~]=(BE  
nStartPos,nEndPos,i); cN{(XmX5n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7{"urs7 T  
fileSplitterFetch.start(); 3zr95$Mt  
} pbXh}YJ&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vJ&g3ky  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); V"A*k^}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |(evDS5  
nEndPos = " + nFileLength); F]fBFDk  
// fileSplitterFetch[nPos.length-1].start(); `l%)0)T  
m|/q o  
fV>12ici  
//等待子线程结束 Z?@oe-mz  
//int count = 0; `]T# uP<u  
//是否结束while循环 zyHHz\{  
boolean breakWhile = false; 2#y-3y<G  
Qp?+G~*  
[B2g{8{!  
while(!bStop) CO<P$al  
{ /Wx({N'h$  
write_nPos(); Kw/7X[|'G  
Utility.sleep(500); %}`zq8Q;  
breakWhile = true; P{2ue`w[  
1:.I0x!  
~uUN\qx52  
for(int i=0;i<nStartPos.length;i++) QTC-W2t]  
{ Ra!Br6  
if(!fileSplitterFetch.bDownOver) D_)i%k\  
{ Yg~$1b@  
breakWhile = false; A.8[FkiNmD  
break; *)8!~Hs   
} 4?u<i=i  
} w4<n=k  
if(breakWhile) >Q-"-X1  
break; ]b+Nsr~  
Szb#:C  
h!zev~u1)`  
//count++; SNUq  
//if(count>4) IEP^u `}  
// siteStop(); zP`&X:8  
} R?D c*,  
GN=ugP 9  
X+$IaLfCxD  
System.err.println("文件下载结束!"); ~BbF:DS  
} y~r5KB6w  
catch(Exception e){e.printStackTrace ();} d#W>"Cqxqa  
} .7`c(9<  
S^z t>  
p~evPTHnrX  
//获得文件长度 \46 'j.  
public long getFileSize() qX%oLa  
{ Y0 ?<~Gf  
int nFileLength = -1; U;q GUqI  
try{ v>!tws5e  
URL url = new URL(siteInfoBean.getSSiteURL()); {gkY:$xnrG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9sId2py]W  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8-_\Q2vG  
r9vO(m~  
rG t/ /6  
int responseCode=httpConnection.getResponseCode(); 6!|/(~  
if(responseCode>=400) 71I: P|.>  
{ ; `Vbl_"L  
processErrorCode(responseCode); 4UISuYg'  
return -2; //-2 represent access is error d95 $w8>  
} NGs@z^&V  
K1oSoD8c  
Qw@_.I  
String sHeader; u|Tg*B  
bMvHAtp  
j96\({;k  
for(int i=1;;i++) ,?KN;~t#vz  
{ D\LXjEm e.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); P:QSr8K  
//Utility.log(in.readLine()); <?E~Qc t  
sHeader=httpConnection.getHeaderFieldKey(i); Oe_*(q&  
if(sHeader!=null) Xf/qUao  
{ $%"?0S  
if(sHeader.equals("Content-Length")) 2t3DQ  
{ (kFg2kG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {+N7o7  
break; WW[Gne  
} n%&+yg   
} )Zbrg~-@  
else 6xT" j)h  
break; g?1! /+  
} wyC1M  
} _!:*&{  
catch(IOException e){e.printStackTrace ();} 4.&hV?Kxz  
catch(Exception e){e.printStackTrace ();} SMMvRF`7  
i!7|YAu  
lG/h[  
Utility.log(nFileLength); d>-k-X-[  
KwxO%/-}S  
d#Xt2   
return nFileLength; (d ?sFwOt\  
} +hL%8CVU M  
vNIQ1x5Za  
YCI- p p  
//保存下载信息(文件指针位置) # M18&ld,r  
private void write_nPos() h3BDHz,  
{ 0NFYFd-50  
try{ cP,bob]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gBPYGci2F  
output.writeInt(nStartPos.length); Sf"]enwB  
for(int i=0;i<nStartPos.length;i++) ? f>pKe  
{ I?~iEO\nh  
// output.writeLong(nPos); /xh/M@G3  
output.writeLong(fileSplitterFetch.nStartPos); aS)Gj?Odf  
output.writeLong(fileSplitterFetch.nEndPos); NB#-W4NA  
} 4lsg%b6_%,  
output.close(); 3?Tk[m1b  
} rL3 f%L  
catch(IOException e){e.printStackTrace ();} M # ) @!  
catch(Exception e){e.printStackTrace ();} =H)"t:xE  
}  X0&[cyP!  
t{g7 :A  
>21f%Z  
//读取保存的下载信息(文件指针位置) 96]!*}  
private void read_nPos() 3{FUFx  
{ L>>Cx`ASi  
try{ tv\_& ({  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i&',g  
int nCount = input.readInt(); `44 }kkBT  
nStartPos = new long[nCount]; -j"]1JLQ  
nEndPos = new long[nCount]; r{ }&* Y  
for(int i=0;i<nStartPos.length;i++) 5fuB((fd(  
{ |x$2- RUP  
nStartPos = input.readLong(); 6ntduXeNVh  
nEndPos = input.readLong(); ]zUvs6ksLG  
} g|V md  
input.close(); w^N3Ma  
} s;!Tz)  
catch(IOException e){e.printStackTrace ();} p)y'a+|7  
catch(Exception e){e.printStackTrace ();} -V 'h>K  
} "&{sE RYY  
am(jmf::  
Kq4b`cn{_  
private void processErrorCode(int nErrorCode) K'u66%wAL  
{ )4CF*>*6V  
System.err.println("Error Code : " + nErrorCode); 5rPK7Jh`B  
} s!eB8lkcT  
{wy#HYhv  
\`N<0COP  
//停止文件下载 QsC6\Gt#  
public void siteStop()  _7P#?:h  
{ r?:xD(}Q  
bStop = true; PZE{- TM?W  
for(int i=0;i<nStartPos.length;i++) S{7 R6,B5  
fileSplitterFetch.splitterStop(); 5FQtlB9F  
[_w;=l0 ;  
S*9qpes-m|  
} vd]75  
} e%K oecq  
//负责部分文件的抓取 n"dYN3dE  
**FileSplitterFetch.java H=1Jq  
*/ hJkF-yW  
package NetFox; YIZ+BVa  
45H(.}&f  
_+NM<o#A  
import java.io.*; YfZ96C[a  
import java.net.*; f>kW\uC  
EI!e0 V1!  
Nub)]S>_/t  
public class FileSplitterFetch extends Thread { bUS"1Tg]*6  
wN^$8m5\T^  
V+- ]txu|  
String sURL; //File URL ON q=bI*  
long nStartPos; //File Snippet Start Position eR*y<K(d  
long nEndPos; //File Snippet End Position Aat-938FP6  
int nThreadID; //Thread's ID #s]'2O  
boolean bDownOver = false; //Downing is over G.y~*5?#  
boolean bStop = false; //Stop identical .!Qo+(  
FileAccessI fileAccessI = null; //File Access interface o'auCa,N  
4 /Q4sE~<  
ed:[^#Lj  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e=#'rDm  
{ >cYYr@S  
this.sURL = sURL; 2uy<wJE >  
this.nStartPos = nStart; ocDAg<wo  
this.nEndPos = nEnd; DF`?D +  
nThreadID = id; | l|7[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }[c ,/NH  
} zd-qQ.j0  
;[R#:Rk  
[Z$E^QAP  
public void run() 7f,!xh$  
{ 2SHS!6:Rl  
while(nStartPos < nEndPos && !bStop) O;m@fS2%3  
{ "GY/2;  
f' 28s*n  
QxS=W2iN  
try{ Ka|, qkb  
URL url = new URL(sURL); C<u<:4^H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u/S{^2`b  
httpConnection.setRequestProperty("User-Agent","NetFox"); &>$+O>c ,  
String sProperty = "bytes="+nStartPos+"-"; 3wf&,4`EX  
httpConnection.setRequestProperty("RANGE",sProperty); y L|'K}  
Utility.log(sProperty); <-rw>,  
#yi&-9B  
?D8 +wj  
InputStream input = httpConnection.getInputStream(); 5*P+c(=  
//logResponseHead(httpConnection); 3rh@|fg)E  
[t}\8^y  
`iT{H]po  
byte[] b = new byte[1024]; v[J"/:]  
int nRead; nlsif  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~]LkQQ'  
{ gt Vnn]Jh  
nStartPos += fileAccessI.write(b,0,nRead); p81Vt   
//if(nThreadID == 1) 8{ooLdpX7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x-%4-)  
} | g[iK1  
~&\}qz3  
/CfgxPo  
Utility.log("Thread " + nThreadID + " is over!"); U2TR>0l  
bDownOver = true;  VsR8|Hn$  
//nPos = fileAccessI.write (b,0,nRead); k3 S  
} I2G:jMPy  
catch(Exception e){e.printStackTrace ();} k/]4L!/ T  
} ] lONi  
} h qT6]*  
|jT^[q(z  
9f U,_`r  
//打印回应的头信息 l Taw6;  
public void logResponseHead(HttpURLConnection con) h =E)5&Z  
{ rD":Gac  
for(int i=1;;i++) }{#ty uzAo  
{ Lw_s'QNWR  
String header=con.getHeaderFieldKey(i); !gbPxfH:6  
if(header!=null) YOE!+MiO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); GX-V|hLaGX  
Utility.log(header+" : "+con.getHeaderField(header)); oTLA&dy@  
else .m/$ku{/J  
break; RW I7eC  
} #ssSs]zl  
} jS<(O o  
SNl% ?j| f  
E=eK(t(8  
public void splitterStop() noL&>G  
{ .XTR HL*:  
bStop = true; ]~!?(d!J/  
} Al-;-t#Dc  
YRRsbm{  
'2X6 >6`w  
} :Y)jf  
n4%ZR~9WH  
$vjl-1x&  
/* MIF`|3$,  
**FileAccess.java S;L=W9=wby  
*//文件访问(定位,写) bpp{Z1/4  
package NetFox; K}e:zR;;^  
import java.io.*; ckhU@C|=*  
E 8LA+dKN:  
{@YY8SKb9  
public class FileAccessI implements Serializable{ }fT5(+ Wo  
:plN<8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ZlG|U]mM5  
RandomAccessFile oSavedFile; 2uZ4$_  
long nPos; 6>=yX6U1q^  
fWk,k*Z 9  
ta+MH,  
public FileAccessI() throws IOException :XFr"aSt  
{ !9p;%Ny`  
this("",0); AS? ESDC  
} 'JK"3m}nT  
kfj)`x  
X"Ca  
public FileAccessI(String sName,long nPos) throws IOException dgp1B\  
{ ($or@lfs  
oSavedFile = new RandomAccessFile(sName,"rw"); Vl\8*!OL%  
this.nPos = nPos; M%(^GdI#Vf  
oSavedFile.seek(nPos); Z`]r)z%f  
} ms%RNxU4:  
hteAuz4H  
4}xw&x  
public synchronized int write(byte[] b,int nStart,int nLen) <reALC  
{ 0Fc^c[  
int n = -1; 0ub0 [A  
try{ 0aM&+j\q}  
oSavedFile.write(b,nStart,nLen); ^I y'G44  
n = nLen; 6 @A'N(I=O  
} dn1Fwy.  
catch(IOException e) ?%A9}"q]  
{ ;Y9-0W  
e.printStackTrace (); ?[VL 2dP0  
} #UesXv  
[L ?^+p>  
{16]8-pe  
return n; R(AS$<p{!>  
} &,8F!)[9  
J5Ovj,[EZ  
Y!qn[,q8  
} r7^oqEp@B  
H5!e/4iz  
1tIJ'#6  
/* 4^(aG7  
**SiteInfoBean.java N}gPf i  
*/ Q&]f9j_  
package NetFox; -qqI @+u+  
f"RS,]  
4..M *U  
public class SiteInfoBean { [JVEKc ym  
ORx6r=zg  
qd<-{  
private String sSiteURL; //Site's URL Lvd es.0|  
private String sFilePath; //Saved File's Path cNl NJ  
private String sFileName; //Saved File's Name cw3j&k  
private int nSplitter; //Count of Splited Downloading File W7#dc89}  
8vqx}2  
vdIert?p  
public SiteInfoBean() Bw/8-:eb  
{//nSplitter的缺省值为5 %urd;h D  
//default value of nSplitter is 5 x:$ xtu  
this("","","",5); V jLv{f<p  
} MSaOFv_Q  
pv]2"|]V)  
m gE r+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ).3riR  
{ J!\oH%FJp  
sSiteURL= sURL; e|}B;<  
sFilePath = sPath; B",;z)(%  
sFileName = sName; Xti.yQx\  
this.nSplitter = nSpiltter; rU9z? (  
["^? vhv  
$uUR@l  
} b.j$Gna>Q  
 alH6~  
}0V aZ<j  
public String getSSiteURL() 4w5);x.  
{ #w@V!o  
return sSiteURL; Qo~|[]GE  
} Ggk#>O G  
`0, G' F  
=}g-N)^  
public void setSSiteURL(String value) mg]t)+PQ  
{ i_(6} Y&  
sSiteURL = value; 4;*jE (  
} HtV8=.^  
N 9W,p 2  
rS8}(lf  
public String getSFilePath() ykYef  
{ m+Kl   
return sFilePath; Ye S5%?Fk  
} s}F.D^^G  
1ixBwnp?  
yV*jc`1  
public void setSFilePath(String value) 0^vz /y1c  
{ Lpohc4d[V  
sFilePath = value; @jCMQYR  
} %xrldn%  
3i1TBhs6  
mw&'@M_(7  
public String getSFileName() {T-=&%||  
{ x[=,$;o+  
return sFileName; 6UI6E)g  
} A0,h 7<i  
a<J< Oc!  
]nNn"_qh  
public void setSFileName(String value) 21O@yNpS$  
{ 2HO2  
sFileName = value; ,rV;T";r  
} }9kn;rb$g  
>n3ig~0d  
nC(Lr,(  
public int getNSplitter() 2@W`OW Njm  
{ y+p"5s"  
return nSplitter; dVg'v7G&V(  
} Ma4eu8  
R"j<C13;%  
CG;+Z-"X  
public void setNSplitter(int nCount) g:Q:cSg<  
{ {n&GZG"f  
nSplitter = nCount; Id1de>:;  
} U1`pY:P  
} MOPHu O{^  
*cZ7?  
M@JW/~p'  
/* nDcH;_<;9a  
**Utility.java h$mGaw vZ~  
*/ [dFe-2u ,$  
package NetFox; \l%##7DRp]  
a6@k*9D>  
|8tKN"QG  
public class Utility { =YIosmr  
# [ +n(  
#&ei  
public Utility() +IMt$}7[  
{ +:W/=C d(h  
ht#,v5oG>f  
EeH ghq  
} \u04m}h]  
%k<+#j6ZH  
//线程睡眠 39MOqVc  
public static void sleep(int nSecond) bI^F (  
{ -Kw7! =_ g  
try{ Kn1T2WSAg  
Thread.sleep(nSecond); ?9%$g?3Z  
} Tq SjL{l%  
catch(Exception e) X#Ob^E%J  
{ v,Zoy|Lu  
e.printStackTrace (); [kTckZv  
} nch#DE8 2  
} f:t j   
6q8PLyIp  
//日志 r9*6=*J|  
public static void log(String sMsg) 65nK1W`i  
{ EEMRy  
System.err.println(sMsg); E62_k 0q  
} Ls+vWfF=#  
Rn`DUYg  
9R">l5u  
public static void log(int sMsg) 4 L 5$=V  
{ JP(0/?Q  
System.err.println(sMsg); RP^vx`9h  
} QyY<Zi;6  
} f$5\ b[O  
_8ks`O#}  
nN^lY=3  
/* < 2fy(9y  
**TestMethod.java =**Q\ Sl  
*/ %%#bTyF  
package NetFox; ;.<HpDfG_  
ZmycK:f  
Jz*A!Li  
public class TestMethod { cj^hwtx   
xj9xUun  
*K& $9fah  
public TestMethod() acgx')!c  
{ ///xx/weblogic60b2_win.exe dWu;F^  
try{ Lxv6\3I+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {;m|\652B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); of GoaH*h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 52NI{"  
fileFetch.start(); J qmL|S)  
} m=Gb<)Y  
catch(Exception e){e.printStackTrace ();} ;Wa&Dg/5`  
p$ETAvD  
yY*(!^S  
} A`Rs n\  
F\v~2/J5v  
=d iGuI B  
public static void main(String[] args) rg=Ym.  
{ K`j:F>b  
new TestMethod(); $~j9{*]5  
} NTO.;S|2%  
} ]>ndFE6kl  
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