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http断点续传简单实现(java)

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/*  <R.Ipyt.  
**SiteFileFetch.java 3"HX':8x  
*/ $dkkgsw 7  
package NetFox; ^nGKuW7\  
import java.io.*; DR c-L$bD  
import java.net.*; 5ji#rIAhxh  
sMHP=2##  
.h=H?Hr(V]  
public class SiteFileFetch extends Thread { m#a1N  
<4,LTB]9-  
g7@.Fa.u'!  
SiteInfoBean siteInfoBean = null; //文件信息Bean 2{oU5e  
long[] nStartPos; //开始位置 ;{:bq`56f  
long[] nEndPos; //结束位置 f*E#E=j  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 V \Sl->:  
long nFileLength; //文件长度 YX{c06BHs  
boolean bFirst = true; //是否第一次取文件 E*G {V j  
boolean bStop = false; //停止标志 ]3&BLq  
File tmpFile; //文件下载的临时信息 gv}J"anD  
DataOutputStream output; //输出到文件的输出流 }Jm~b9j  
%z "${ zw  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) SsfHp  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7j~}M(s"  
{ &{z RuF  
siteInfoBean = bean; (>M? iB  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); P`TJqJiY~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); CEl9/"0s6  
if(tmpFile.exists ()) G/y;o3/[Z  
{ >^ TcO  
bFirst = false; {}DoRp q=  
read_nPos(); .F^372hH3  
} JGG(mrvR  
else 7L !$hk  
{ W`gzMx  
nStartPos = new long[bean.getNSplitter()]; fZNe[|  
nEndPos = new long[bean.getNSplitter()]; k#DMd9  
} mr<camL5  
_,bDv`>Ra  
C<yjGt VD  
G^&P'*  
} ?CSv;:  
4ztU) 1  
%pBc]n@_  
public void run() Z>(K|3_  
{ =niT]xf  
//获得文件长度 @*^%^ P  
//分割文件 TS49{^d$  
//实例FileSplitterFetch Y |'}VU  
//启动FileSplitterFetch线程 .)[0yW&  
//等待子线程返回 HMl M!Xk?  
try{ s]'EIw}mo  
if(bFirst) ,ocAB;K  
{ @G?R (  
nFileLength = getFileSize(); YF6 8 Ax]  
if(nFileLength == -1) Cd'`rs}3  
{ D]NJ ^.X  
System.err.println("File Length is not known!"); _ 0h)O  
} B'8T+qvA  
else if(nFileLength == -2) |}D5q| d@n  
{ H J0Rcw%  
System.err.println("File is not access!"); {vox x&UX  
} ='Fh^]*5  
else ~U+W4%f8  
{ 3F?_{A  
for(int i=0;i<nStartPos.length;i++) q"$C)o  
{ 8Bwm+LYr-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NT;cTa=;  
} rt C:3fDy  
for(int i=0;i<nEndPos.length-1;i++) O*udVE>  
{ 6~tj"34_  
nEndPos = nStartPos[i+1]; BXa.XZ<n(  
} v%E~sX&CG  
nEndPos[nEndPos.length-1] = nFileLength; ykD-L^}  
} 4`'V%)M  
}  s4vj  
Kdr} 7#c  
IXC2w *'m  
//启动子线程 "] [u  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; pz ~REsx  
for(int i=0;i<nStartPos.length;i++) Hd89./v`:  
{ Mt\.?V:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e {805^X}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *^i"q\n5(  
nStartPos,nEndPos,i); h {VdW}g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W-<`Vo'  
fileSplitterFetch.start(); 8 Az|SJ<  
} {Y1&GO;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I]6,hygs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $ 9 k5a  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3"LT''  
nEndPos = " + nFileLength); +@qIDUiF3  
// fileSplitterFetch[nPos.length-1].start(); m_h$fT8 _  
U$ Od)  
o(eh.  
//等待子线程结束 _|wnmeL*  
//int count = 0; Eu2(#z 6eW  
//是否结束while循环 GxS!Lk  
boolean breakWhile = false; jQ3&4>gj  
BDT"wy8  
iH>IV0 <  
while(!bStop) =?[:Nj636  
{ (CrP6]=  
write_nPos(); BY>]6SrP  
Utility.sleep(500); hUe\sv!x?  
breakWhile = true; n*rXj{Kt  
BE)&.}l  
@B Muov  
for(int i=0;i<nStartPos.length;i++) =F/EzS  
{ / 5y _ <  
if(!fileSplitterFetch.bDownOver) V>& 1;n  
{ Yd]  
breakWhile = false; a^7QHYJ6  
break; b]g#mQ  
}  V0!kvIv  
} `Ln1g@  
if(breakWhile) 6 jU ?~  
break; 8f>v[SQ"  
iM M s3  
cS(=wC  
//count++; ?D['>Rzu  
//if(count>4) @nOuFX4  
// siteStop(); 2[i(XG{/  
}  3 EOuJ  
FZtT2Z4&i  
L b-xc]  
System.err.println("文件下载结束!"); wo9`-o6  
} ;^cMP1SH  
catch(Exception e){e.printStackTrace ();} tY%T  
} -%TwtO<$']  
-q&7q  
X/FRe[R  
//获得文件长度 G6pR?K+  
public long getFileSize() V)]lca  
{ +do* C =z  
int nFileLength = -1; RmJ|g<  
try{ J~)JsAXAI  
URL url = new URL(siteInfoBean.getSSiteURL()); uvJmEBL:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V\=%u<f  
httpConnection.setRequestProperty("User-Agent","NetFox"); py$i{v%  
emIF{oP  
6\USeZh  
int responseCode=httpConnection.getResponseCode(); @?5pY^>DK  
if(responseCode>=400) @./ @"mR<  
{ *0Wkz'=U  
processErrorCode(responseCode); J3hhh(  
return -2; //-2 represent access is error V$bq|r  
} \-D[C+1(  
jJAr #|  
CEJqo8ds  
String sHeader; F%$l cQ04%  
F`CDv5  
Sobp;OZ5  
for(int i=1;;i++) 3:bP>l!  
{ Kl]l[!c7$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \qJ cs'D  
//Utility.log(in.readLine()); r=#v@]z B  
sHeader=httpConnection.getHeaderFieldKey(i); `$ pJ2S  
if(sHeader!=null) @ 1FWBH~  
{ jQ['f\R  
if(sHeader.equals("Content-Length")) [ nLd>2P  
{ _ygdv\^Tet  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,15$$3z/E  
break; zS '{F>w  
} ! q+>'Mt  
} ]CX^!n  
else zC`ediyu  
break; e#@u&+K/f  
} irMBd8WG  
} Ct]? /  
catch(IOException e){e.printStackTrace ();} /w2NO9Q  
catch(Exception e){e.printStackTrace ();} F41gMg  
4%7Oaf>9  
rEoOv  
Utility.log(nFileLength); 0yxwsBLy  
@B9#Hrc  
w:2yFC  
return nFileLength; ]W7&ZpF  
} O@>{%u  
at(gem  
(I;lE*>  
//保存下载信息(文件指针位置) A_+*b [P  
private void write_nPos() R)Dh;XA  
{ [ZD`t,x(  
try{ X/H2c"!t  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )2J#pz?.  
output.writeInt(nStartPos.length); EUS^Gtc  
for(int i=0;i<nStartPos.length;i++) 1-Q>[Uz,  
{ ceAefKdb  
// output.writeLong(nPos); Ryn@">sVI  
output.writeLong(fileSplitterFetch.nStartPos); u?KG%  
output.writeLong(fileSplitterFetch.nEndPos); +f,I$&d.V  
} r@ba1*y0  
output.close(); Qm4cuV-0{  
} 5Zl7crA[  
catch(IOException e){e.printStackTrace ();} }DQ[C&  
catch(Exception e){e.printStackTrace ();} 9`!#5i)VU8  
} /Q'O]h0a  
W3&~[DS@~  
Ox6^=D "  
//读取保存的下载信息(文件指针位置) TSj)XU {W  
private void read_nPos() \b?O+;5Cj  
{ XlJ+:st  
try{ 1~[GGl  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~e=KBYDBu  
int nCount = input.readInt(); S9 @*g3  
nStartPos = new long[nCount]; 5K00z?kD2V  
nEndPos = new long[nCount]; M] W5 %3do  
for(int i=0;i<nStartPos.length;i++) LP) IL~  
{ QY$4D;M`g6  
nStartPos = input.readLong(); =<U'Jtu6'  
nEndPos = input.readLong(); sNJ?Z"5k1h  
} P c vA/W  
input.close(); u43-\=1$T  
} ihIRB9  
catch(IOException e){e.printStackTrace ();} \{1Vjo  
catch(Exception e){e.printStackTrace ();} xt8@l [Z  
} Co`:D  
~HXZ-*  
)T@+"Pw8t  
private void processErrorCode(int nErrorCode) M B,Z4 ^  
{ %Gm4,+8P3o  
System.err.println("Error Code : " + nErrorCode); J=ot& %  
} fw0Z- 9*  
N~B'gJJDx  
N}q*(r!q<  
//停止文件下载 r8!M8Sc  
public void siteStop() /P*ph0S-  
{ #M92=IH  
bStop = true; D$SO 6X~  
for(int i=0;i<nStartPos.length;i++) o Hrx$>W]  
fileSplitterFetch.splitterStop(); 4<U6jB5  
@fd{5 >\  
a!:R_P}7  
} LsNJ3oy  
} /7C %m:  
//负责部分文件的抓取 cQ/T:E7$`  
**FileSplitterFetch.java s=n_(}{ q  
*/ l%7^'nDn  
package NetFox; w4Ku1G#jC  
_2WIi/6K  
M:w]g`LKl  
import java.io.*; ~T&X#i  
import java.net.*; u!cA_,  
T\L LOx\  
e{d$OzT) V  
public class FileSplitterFetch extends Thread { ;\t(c  
ni3A+Y0  
V,:~FufM^  
String sURL; //File URL 8C2!Wwz`J8  
long nStartPos; //File Snippet Start Position .vXe}%  
long nEndPos; //File Snippet End Position 2|LkCu)~,"  
int nThreadID; //Thread's ID y#5;wb<1  
boolean bDownOver = false; //Downing is over t8-LPq  
boolean bStop = false; //Stop identical eXMl3Lxf  
FileAccessI fileAccessI = null; //File Access interface C-ipxL"r  
HO;,Ya^l  
}pv<<7}|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException U KdCG.E9^  
{ jI807g+  
this.sURL = sURL; vC5y]1QDd  
this.nStartPos = nStart; eh$T 3_#q  
this.nEndPos = nEnd; q.PXO3T  
nThreadID = id; L!kbDbqn  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ib$?[  
} ;EfREfk  
3(La)|k  
_95`w9  
public void run() p\M\mK  
{ c(0Ez@  
while(nStartPos < nEndPos && !bStop) 1 *$-.  
{ 5[$jrG\!  
>]WQ1E[=  
z=VL|Du1OT  
try{ h:'wtn@l(  
URL url = new URL(sURL); o^~KAB7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Le}-F{~`^  
httpConnection.setRequestProperty("User-Agent","NetFox"); X3rvM8  
String sProperty = "bytes="+nStartPos+"-"; O.+X,CQG*  
httpConnection.setRequestProperty("RANGE",sProperty); +jX.::UPm  
Utility.log(sProperty); l%$co07cX  
(Y]G6> Oa  
PQ[x A*  
InputStream input = httpConnection.getInputStream(); w\ 7aAf3O  
//logResponseHead(httpConnection); )NS& 1$  
=k22f`8ew  
8VZLwhj  
byte[] b = new byte[1024]; O PVc T  
int nRead; \}mn"y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #me'1/z  
{ p*(]8pDC  
nStartPos += fileAccessI.write(b,0,nRead); V .VV:`S  
//if(nThreadID == 1) Fs)m;C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .=4k'99,  
} v"G)G)*z  
d/`Q,Vl  
UI.>BZ6}  
Utility.log("Thread " + nThreadID + " is over!"); uSK<{UT~3  
bDownOver = true; |#-GH$.v  
//nPos = fileAccessI.write (b,0,nRead); ~gvw6e*[  
} {F+iL&e)  
catch(Exception e){e.printStackTrace ();} n:[GK_  
} 9dD;Z$x&Xk  
} zAdZXa[MRY  
;?0r,0l2$  
En/EQ\T@F  
//打印回应的头信息 "+:IA|1wD  
public void logResponseHead(HttpURLConnection con) ar| !iU  
{ E`>u*D$un~  
for(int i=1;;i++) 5A=FEg  
{ ]QAMCu(>  
String header=con.getHeaderFieldKey(i); 9 ~$' ?  
if(header!=null) Gfn?1Kt{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?_7^MP>  
Utility.log(header+" : "+con.getHeaderField(header)); lGtTZ cg  
else " )_-L8  
break; [boB4>.  
} kI>PaZ`i)  
} eC41PQ3=1'  
+=A53V[C  
EAM2t|M G.  
public void splitterStop() YX:[],FP  
{ Kwa$5qZI  
bStop = true; -Lbi eS%  
} B7!dp`rPp  
w>ap8><4  
!*l5%H  
} Sx3R 2-!Z  
Z>zW83a  
G;3N"az  
/* OwM.N+ z#T  
**FileAccess.java {y k0Zef_  
*//文件访问(定位,写) jh&WL  
package NetFox; 4w5mn6MxR  
import java.io.*; u$?t |Ll  
R3=]Av46  
THbV],RhJ  
public class FileAccessI implements Serializable{ Iib39?D W  
O}IRM|r"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V,CVMbn/%N  
RandomAccessFile oSavedFile; IDpW5Dc  
long nPos; mlD 1 o  
d=_Wgz,d  
+sc--e?  
public FileAccessI() throws IOException wO {-qrN  
{ &p2fMVWJ7  
this("",0); !Yan}{A,  
} =fr_` "?k  
_<i*{;kR6  
# U j~F  
public FileAccessI(String sName,long nPos) throws IOException 12,,gwh  
{ <>FpvdB  
oSavedFile = new RandomAccessFile(sName,"rw"); ;,yjkD[mWE  
this.nPos = nPos; _ X* A  
oSavedFile.seek(nPos); L'?0*t  
} !:^lTvYWZH  
q|+`ihut  
T[YGQT|B  
public synchronized int write(byte[] b,int nStart,int nLen) wJQ"|  
{ otgU6S7F  
int n = -1; y.:Z:w6$  
try{ b0_Ih6  
oSavedFile.write(b,nStart,nLen); $h( B2  
n = nLen; "2'pS<|  
} PV_q=70%T  
catch(IOException e) w_hGWpm  
{ 7FiQTS B:  
e.printStackTrace (); Tp7slKc0p  
} 41[1_p(  
xrPC  
 qg+bh  
return n; p7pJ90~E  
} (wRJ"Nwu  
&gL &@';,  
lp;= f  
} D!oELZ3  
+w]KK6  
9 ZD4Gv   
/* Lh(` 9(tX  
**SiteInfoBean.java cj!Ew}o40D  
*/ g}B|ZRz+{  
package NetFox; @m=xCg.Z  
b&V}&9'[M;  
I;<aJo6Yl  
public class SiteInfoBean { EhOy<f[4W  
sX~ `Vn&  
m%bw$hr  
private String sSiteURL; //Site's URL 7:D@6<J?  
private String sFilePath; //Saved File's Path >;A7mi/  
private String sFileName; //Saved File's Name _K?{DnTb  
private int nSplitter; //Count of Splited Downloading File 2/c^3[ccR  
oe8sixZ[  
L/VlmN_v>s  
public SiteInfoBean() $C;)Tlh  
{//nSplitter的缺省值为5 dSkW[r9Z%l  
//default value of nSplitter is 5 E?z~)0z2`  
this("","","",5); ^at X/  
} cN5,\I.  
9y~5@/3 2R  
nKzS2 u=:Y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @,Iyn<v{B  
{ `bJ+r)+5  
sSiteURL= sURL; 8a^E{x@HT  
sFilePath = sPath; fgW>U*.ar  
sFileName = sName; X7*i -v@  
this.nSplitter = nSpiltter; R4V~+tnbG&  
v?U;o&L(  
g(i_di  
} ugwZAC  
XRMYR97  
FKOTv2  
public String getSSiteURL() 12yr_   
{ SGd[cA Ko  
return sSiteURL; _^2rRz  
} hw@ `Q@  
e7(iMe  
OUd&fUmH  
public void setSSiteURL(String value) QD6in>+B@  
{ t@`w}o[#  
sSiteURL = value; _i=431Z40  
} 7$l!f  
._uXK[c7P  
"lFS{7  
public String getSFilePath() ^11y8[[  
{ }J~ d6m  
return sFilePath; %q~YJ*\  
} e-Xr^@M*Q  
fr\"MP  
H}R/_5g  
public void setSFilePath(String value) fq@r6\TI  
{ :/c40:[  
sFilePath = value; ZB)`*z>*  
} k_E Jg;(  
pQGlg[i2/  
f(^? PGO  
public String getSFileName() 4pin\ZS:C  
{ 29xm66  
return sFileName; x.+r.cAXH  
} tJ{3Z}K  
F ka^0  
(9#$za>  
public void setSFileName(String value) *?2aIz"  
{ &DX&*Xq2  
sFileName = value; /Ria"lLv  
} % Rv ;e  
/E/Z0<l7  
qSg#:;(O  
public int getNSplitter() J <"=c z$  
{ y_>l'{w3^  
return nSplitter; + [JvpDv%  
} ^~3u|u  
@B@`V F  
"Cj {Z@n  
public void setNSplitter(int nCount) &tNnW   
{ <6 HrHw_  
nSplitter = nCount; KI@OEy  
} 4jOq.j  
} X 5.%e&`  
1Mftq4nq  
A#yZh\#  
/* "Je*70LG#  
**Utility.java fEdp^oVg  
*/ eSqKXmH[m  
package NetFox; +b =X~>vZ  
3Kx&+  
=bx;TV  
public class Utility { TpB4VNi/<  
#2/2X v  
zS9HR1  
public Utility() `b11,lg  
{ !mjrI "_  
-`I&hzl6E  
^\ N@qL  
} #~_ZG% u  
|61W-9;  
//线程睡眠 5f~49(v]  
public static void sleep(int nSecond) }{R?i,j(  
{ I"=a:q  
try{ c#ahFpsnlw  
Thread.sleep(nSecond); 6njwrqo  
} %nRz~3X|+v  
catch(Exception e) 9JDdOjqo  
{ c'wxCqnE   
e.printStackTrace (); Y<]A 5cm  
} w$aiVOjgT  
} X6T*?t3!9[  
\>DMN #  
//日志 dR9[K4`p/  
public static void log(String sMsg) m]7oTmS  
{ n$*e(  
System.err.println(sMsg); L@|xpq  
} #OQT@uF!  
T 5AoBUw  
KW&vX%i(.  
public static void log(int sMsg) Z[, A>tJ  
{ kBRy(?Mft&  
System.err.println(sMsg); j>}<FW-N  
} qg`8f?  
} 6>X9|w  
5DI&pR1eZ  
<>Nq ]WqA  
/* ?o D]J  
**TestMethod.java 5x2m ]u  
*/ 6EX_IDb  
package NetFox; ;8~tt I  
< Z>p1S  
nNEIwlj;  
public class TestMethod { J7RO*.O&Iq  
'm4v)w<y#  
JZUf-0q  
public TestMethod() !4/s|b9K  
{ ///xx/weblogic60b2_win.exe f\|R<3 L  
try{ \FL`b{!+ N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4Odf6v,*@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6^+T_{gl  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >Oz~j>jL  
fileFetch.start(); xoYaL  
} G@N-+  
catch(Exception e){e.printStackTrace ();} >.76<fni  
smJ#.I6/L  
O$K?2-  
} L'@@ewA  
C-TATH%f^  
K:JM*4W  
public static void main(String[] args) A7hWAq  
{ a3Fe42G2c|  
new TestMethod(); '",+2=JJ  
} 0sR+@\  
} |EjMpRNE  
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